Electrical Standard

Federal RegisterFeb 14, 2007

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DEPARTMENT OF LABOR

Occupational Safety and Health Administration

29 CFR Part 1910

[Docket No. S-108C]

RIN 1218-AB95

Electrical Standard

AGENCY:

Occupational Safety and Health Administration, Labor.

ACTION:

Final rule.

SUMMARY:

The Occupational Safety and Health Administration (OSHA) is revising the general industry electrical installation standard found in Subpart S of 29 CFR Part 1910. The Agency has determined that electrical hazards in the workplace pose a significant risk of injury or death to employees, and that the requirements in the revised standard, which draw heavily from the 2000 edition of the National Fire Protection Association's (NFPA) Electrical Safety Requirements for Employee Workplaces (NFPA 70E), and the 2002 edition of the National Electrical Code (NEC), are reasonably necessary to provide protection from these hazards. This final rule focuses on safety in the design and installation of electric equipment in the workplace. This revision will provide the first update of the installation requirements in the general industry electrical installation standard since 1981.

OSHA is also replacing the reference to the 1971 NEC in the mandatory appendix to the general industry powered platform standard found in Subpart F of 29 CFR Part 1910 with a reference to OSHA's electrical installation standard.

DATES:

This final rule becomes effective on August 13, 2007.

ADDRESSES:

In accordance with 28 U.S.C. 2112(a), the Agency designates the Associate Solicitor of Labor for Occupational Safety and Health, Office of the Solicitor of Labor, Room S4004, U.S. Department of Labor, 200 Constitution Avenue, NW., Washington, DC 20210, to receive petitions for review of the final rule.

FOR FURTHER INFORMATION CONTACT:

For general information and press inquiries, contact Mr. Kevin Ropp, Director, Office of Communications, Room N-3647, OSHA, U.S. Department of Labor, 200 Constitution Avenue, NW., Washington, DC 20210; telephone (202) 693-1999. For technical inquiries, contact Mr. David Wallis, Directorate of Standards and Guidance, Room N-3609, OSHA, U.S. Department of Labor, 200 Constitution Avenue, NW., Washington, DC 20210; telephone (202) 693-2222.

For additional copies of this

Federal Register

notice, contact OSHA, Office of Publications, Room N-3101, U.S. Department of Labor, 200 Constitution Avenue, NW., Washington, DC 20210; telephone (202) 693-1888. Electronic copies of this

Federal Register

notice, as well as news releases and other relevant documents, are available at OSHA's Web page on the Internet at

http://www.osha.gov

SUPPLEMENTARY INFORMATION:

I. Introduction

This final rule revises OSHA's existing standard for electrical installations, which is contained in §§ 1910.302 through 1910.308 of Subpart S, with relevant definitions in § 1910.399. It applies, as the existing standard does, to employers in general industry and in shipyard employment, longshoring, and marine terminals.

OSHA undertook the project to revise Subpart S for two major reasons. First, the Agency wanted the standard to reflect the most current practice and technology in the industry. The existing standard is based on a national consensus standard, the 1979 edition of Part I of NFPA 70E, entitled Standard for Electrical Safety Requirements for Employee Workplaces. That consensus standard has been updated several times since OSHA last revised its electrical installation requirements in 1981. The final rule being published today is based on Part I of the 2000 edition of NFPA 70E. Second, in implementing this rule, OSHA is responding to requests from stakeholders that the Agency revise Subpart S so that it reflects the most recent editions of NFPA 70E and the NEC.

These stakeholders argued that interested members of the public have had substantial input into the content of NFPA 70E and that industry is complying with that consensus standard in its present form. The revised standard will be more flexible and efficient for stakeholders, including small businesses, while improving safety for employees.

See, for example, letters from: Judith Gorman, Managing Director of the Institute of Electrical and Electronic Engineers; George D. Miller, President and Chief Executive Officer of the National Fire Protection Association; Frank K. Kitzantides, Vice President of Engineering at the National Electrical Manufacturers Association; and Kari P. Barrett, Director of Regulatory and Technical Affairs, Plant Operations, at the American Chemistry Council (Exhibit 2-62, 2-63, 2-64, 2-65).

OSHA's existing electrical standard in §§ 1910.302 through 1910.308 is based on the 1979 edition of NFPA 70E, which is a national consensus standard developed by a cross section of industry, labor, and other allied interests. Consensus standards like the NEC and NFPA 70E provide nationally recognized safe electrical installation requirements. Additionally, the consensus process used in developing the 2000 edition of NFPA 70E, Part 1 of which is based on the NEC, ensures that requirements contained in that standard are current and at the forefront of electrical safety technology. Because the primary objective of this revision of Subpart S is to update the standard to recognize, and in some cases require, the more current electrical safety technology, OSHA believes that the more recent editions of NFPA 70E should be the foundation of the final standard.

Lastly, the Agency has determined that electrical hazards in general industry workplaces pose a significant risk and that the final standard will substantially reduce that risk.

A newer edition of NFPA 70E was published shortly after OSHA issued the proposed rule. Whether the final rule should be based on this edition, NFPA 70E-2004, is one of the issues raised by comments on the proposal. See the discussion of this issue in section V, Summary and Explanation of the Final Standard.

The remainder of the preamble discusses the background of the final rule, the history of the standard, and the legal authority for the standard; provides a summary and explanation of the final standard; includes the final economic and regulatory flexibility analysis and the information collections associated with the rule; and covers other miscellaneous topics. The outline of the preamble is as follows:

I. Introduction

II. Background

III. History of the Standard

IV. Legal Authority

V. Summary and Explanation of the Final Standard

VI. Final Economic and Regulatory Screening Analysis

VII. State Plan Standards

VIII. Environmental Impact Analysis

IX. Unfunded Mandates

X. Federalism

XI. OMB Review under the Paperwork Reduction Act of 1995

XII. Effective Date and Date of Application

II. Background

A. Hazards Associated With Electricity

Electricity is widely recognized as a serious workplace hazard, exposing employees to electric shock, burns, fires, and explosions. According to the Bureau of Labor Statistics, 289 employees were killed by contact with electric current in 2002 (Ex. 2-8). Other employees have been killed or injured

in fires and explosions caused by electricity.

It is well known that the human body will conduct electricity. If direct body contact is made with an electrically energized part while a similar contact is made simultaneously with another conductive surface that is maintained at a different electrical potential, a current will flow, entering the body at one contact point, traversing the body, and then exiting at the other contact point, usually the ground. Each year many employees suffer pain, injuries, and death from such electric shocks.

Current through the body, even at levels as low as 3 milliamperes, can also cause injuries of an indirect or secondary nature in which involuntary muscular reaction from the electric shock can cause bruises, bone fractures and even death resulting from collisions or falls.

Burns suffered in electrical accidents can be very serious. These burns may be of three basic types: electrical burns, arc burns, and thermal contact burns. Electrical burns are the result of the electric current flowing in the tissues, and may be either skin deep or may affect deeper layers (such as muscles and bones) or both. Tissue damage is caused by the heat generated from the current flow; if the energy delivered by the electric shock is high, the body cannot dissipate the heat, and the tissue is burned. Typically, such electrical burns are slow to heal. Arc burns are the result of high temperatures produced by electric arcs or by explosions close to the body. Finally, thermal contact burns are those normally experienced from the skin contacting hot surfaces of overheated electric conductors, conduits, or other energized equipment. In some circumstances, all three types of burns may be produced simultaneously.

If the current involved is great enough, electric arcs can start a fire. Fires can also be created by overheating equipment or by conductors carrying too much current. Extremely high-energy arcs can damage equipment, causing fragmented metal to fly in all directions. In atmospheres that contain explosive gases or vapors or combustible dusts, even low-energy arcs can cause violent explosions.

B. Nature of Electrical Accidents

Electrical accidents, when initially studied, often appear to be caused by circumstances that are varied and peculiar to the particular incidents involved. However, further consideration usually reveals the underlying cause to be a combination of three possible factors: work involving unsafe equipment and installations; workplaces made unsafe by the environment; and unsafe work performance (unsafe acts). The first two factors are sometimes considered together and simply referred to as unsafe conditions. Thus, electrical accidents can be generally considered as being caused by unsafe conditions, unsafe acts, or, in what is usually the case, combinations of the two. It should also be noted that inadequate maintenance can cause equipment or installations that were originally considered safe to deteriorate, resulting in an unsafe condition.

Some unsafe electric equipment and installations can be identified, for example, by the presence of faulty insulation, improper grounding, loose connections, defective parts, ground faults in equipment, unguarded live parts, and underrated equipment. The environment can also be a contributory factor to electrical accidents in a number of ways. Environments containing flammable vapors, liquids, or gases; areas containing corrosive atmospheres; and wet and damp locations are some unsafe environments affecting electrical safety. Finally, unsafe acts include the failure to deenergize electric equipment when it is being repaired or inspected or the use of tools or equipment too close to energized parts.

C. Protective Measures

There are various ways of protecting employees from the hazards of electric shock, including insulation and guarding of live parts. Insulation provides a barrier to the flow of current. To be effective, the insulation must be appropriate for the voltage, and the insulating material must be undamaged, clean, and dry. Guarding prevents the employee from coming too close to energized parts. It can be in the form of a physical barricade, or it can be provided by installing the live parts out of employees’ reach. (This technique is known as “guarding by location.”)

Grounding is another method of protecting employees from electric shock; however, it is normally a secondary protective measure. To keep guards or enclosures at a common potential with earth, they are connected, by means of a grounding conductor, to ground. In addition, grounding provides a path of low impedance and of ample capacity back to the source to pass enough current to activate the overcurrent devices in the circuit. If a live part accidentally contacts a grounded enclosure, current flow is directed back to earth, and the circuit protective devices (for example, fuses and circuit breakers) can interrupt the circuit.

If it draws too much current, electric equipment can overheat, which can result in fires. Overheating can also lead to electric shock hazards if the insulation protecting a conductor melts. Protecting electric equipment from overcurrent helps prevent this from happening.

Designing and installing equipment to protect against dangerous arcing and overheating is also important in preventing unsafe conditions that can lead to fires, high energy electric arcs, and explosions. Employers and employees cannot usually detect improperly designed or rated equipment. Thus, OSHA relies on third-party testing and certification of electric equipment to ensure proper electrical design. This helps ensure, for example, that equipment will not overheat during normal operation and that equipment designed for use in a hazardous location will not cause a fire or explosion. It also helps ensure that equipment is appropriately rated and marked, allowing employees designing electrical installations and installing electric equipment to select equipment and size conductors in accordance with those ratings.

Many of the requirements in OSHA's electrical standards in turn depend on accurate ratings on equipment.

Electric equipment is typically rated for use with certain voltages and current. For example, an electric hair dryer might be rated at 125 volts, 1875 watts. The voltage rating indicates the maximum voltage for which the equipment is rated. The wattage rating indicates how much power the equipment will draw when connected to a circuit at the maximum voltage. The current drawn by the equipment is the wattage rating divided by the voltage rating. Thus, the circuit voltage (120 volts, nominal) is less than the maximum rated voltage of the hair dryer (125 volts), and the circuit is rated for the current the equipment will draw (1875 watts/125 volts = 15 amperes). Thus, the hair dryer would be suitable for use on a 120-volt circuit capable of safely carrying 15 amperes.

These protective measures help ensure the safe installation of electric equipment and are prescribed by the requirements presently contained in 29 CFR Part 1910, Subpart S. Addressing common unsafe conditions, these rules cover such safety considerations as guarding and insulation of live parts, grounding of equipment enclosures, and protection of circuits from overcurrent. This rulemaking updates those requirements to make them consistent with the latest editions of NFPA 70E. This revision will better protect employees by recognizing the latest techniques in electrical safety and by requiring installations to incorporate those techniques whenever necessary.

D. Significant Risk and Reduction in Risk

As stated earlier, electricity has long been recognized as a serious workplace hazard exposing employees to dangers such as electric shock, electrocution, fires, and explosions. The 100-year-long history of the National Electrical Code, originally formulated and periodically updated by industry consensus, attests to this fact. The NEC has represented the continuing efforts of experts in electrical safety to address these hazards and provide standards for limiting exposure in all electrical installations, including workplaces. OSHA has determined that electrical hazards in the workplace pose a significant risk of injury or death to employees and that this final rule, which draws heavily on the experience of the NEC, will substantially reduce this risk.

According to the U.S. Bureau of Labor Statistics, between 1992 and 2002, an average of 295 employees died per year from contact with electric current, and between 1992 and 2001 an average of 4,309 employees lost time away from work because of electrical injuries.

Overall, there has been a downward trend in injuries and illnesses, but the percentage has varied from year to year. From 1992 to 2001, the number of injuries involving days away from work decreased by 29 percent. From 1992 to 2002, the number of deaths decreased by 9 percent. This downward trend is due, in major part, to 30 years of highly protective OSHA regulation in the area of electrical installation, based on the NEC and NFPA 70E standards. The final standard carries forward most of the existing requirements for electrical installations, with the new and revised requirements intended as fine tuning, introducing new technology along with other improvements in safety. By complying with the final standard, employers will prevent unsafe electrical conditions from occurring.

The Survey of Occupational Injuries and Illnesses and the Census of Fatal Occupational Injuries,

http://www.bls.gov/iif/home.htm#tables

While the number of deaths and injuries associated with electrical hazards has declined, contact with electric current still poses a significant risk to employees in the workplace, as evidenced by the numbers of deaths and serious injuries still occurring due to contact with electric current. This final rule will help further reduce the number of deaths and injuries associated with electrical hazards by providing additional requirements for installation safety and by recognizing alternative means of compliance.

III. History of the Standard

On February 16, 1972, OSHA incorporated the 1971 edition of the National Fire Protection Association's (NFPA) National Electrical Code (NEC), NFPA 70-1971, by reference as its electrical standard for general industry (37 FR 3431). The Agency followed the procedures outlined in Section 6(a) of the Occupational Safety and Health Act of 1970 (OSH Act; 29 U.S.C. 655), which directed the Secretary to adopt existing national consensus standards as OSHA standards within 2 years of the effective date of the OSH Act. In incorporating the 1971 NEC by reference, OSHA made the entire 1971 NEC applicable to all covered electrical installations made after March 15, 1972. For covered installations made before that date, OSHA listed about 16 provisions from the 1971 NEC that applied. No other provisions of the 1971 NEC applied to these older installations. Thus, older installations were “grandfathered” so that they did not need to meet most of the requirements in the consensus standard.

On January 16, 1981, OSHA revised its electrical installation standard for general industry (46 FR 4034). This revision replaced the incorporation by reference of the 1971 NEC with relevant requirements from Part I of the 1979 edition of NFPA 70E. The revision simplified and clarified the electrical standard and updated its provisions to match the 1978 NEC (the latest edition available at the time). The standard was written to reduce the need for frequent revision and to avoid technological obsolescence. These goals were achieved—NFPA 70E had only minor changes over its initial 15 years of existence. The first substantial changes were introduced in the 1995 edition of NFPA 70E.

The 2000 edition of NFPA 70E contains a number of significant revisions, including a new, alternative method for classifying and installing equipment in Class I hazardous locations (see preamble Section I. N. Zone Classification, below). NFPA has recommended that OSHA revise its general industry electrical standards to reflect the latest edition of NFPA 70E, arguing that such a revision would provide a needed update to the OSHA standards and would better protect employees. This final rule responds to NFPA's recommendations with regard to installation safety. It also reflects the Agency's commitment to update its electrical standards, keep them consistent with NFPA standards, and ensure that they appropriately protect employees. The Agency intends to extend this commitment by using NFPA 70E as a basis for future revisions to its electrical safety-related work practice requirements and new requirements for electrical maintenance and special equipment.

The proposed rule was published in the

Federal Register

on April 5, 2004. The public had a 60-day comment period that ended on June 4, 2004. OSHA received 38 comments on the proposed revision of OSHA's electrical installation standard for general industry. The Agency received one hearing request on the proposal, which was subsequently withdrawn.

The comments addressed specific provisions in the proposal and raised several issues, including: (1) Whether OSHA should use the latest edition of NFPA 70E or the NEC to revise Subpart S; (2) whether OSHA should update the corresponding construction standard at the same time; (3) whether OSHA should address work practices and other revised provisions of NFPA 70E; and (4) what the effective date of the standard should be. (See section V, “Summary and Explanation of the Final Standard,” later in the preamble, for a discussion of the comments.)

IV. Legal Authority

The purpose of the OSH Act, 29 U.S.C. 651 et seq., is “to assure so far as possible every working man and woman in the Nation safe and healthful working conditions and to preserve our human resources.” 29 U.S.C. 651(b). To achieve this goal, Congress authorized the Secretary of Labor to promulgate and enforce occupational safety and health standards. 29 U.S.C. 655(b) & 658.

A safety or health standard “requires conditions, or the adoption or use of one or more practices, means, methods, operations, or processes, reasonably necessary or appropriate to provide safe or healthful employment and places of employment.” 29 U.S.C. 652(8). A standard is reasonably necessary or appropriate within the meaning of Section 652(8) if:

• A significant risk of material harm exists in the workplace and the proposed standard would substantially reduce or eliminate that workplace risk;

• It is technologically and economically feasible;

• It employs the most cost effective protective measures;

• It is consistent with prior Agency action or supported by a reasoned justification for departing from prior Agency action;

• It is supported by substantial evidence; and

• In the event the standard is preceded by a consensus standard, it is better able to effectuate the purposes of the OSH Act than the standard it supersedes.

International Union, UAW

OSHA (LOTO II),

37 F.3d 665, 668 (D.C. Cir. 1994).

OSHA has generally considered an excess risk of 1 death per 1000 employees over a 45-year working lifetime as clearly representing a significant risk (see

Industrial Union Dept.

American Petroleum Institute (Benzene),

448 U.S. 607, 655 (1980);

International Union

Pendergrass (Formaldehyde),

878 F.2d 389, 392-93 (D.C. Cir. 1989);

Building and Construction Trades Dept., AFL-CIO

Brock (Asbestos),

838 F.2d 1258, 1264-65 (D.C. Cir. 1988)).

A standard is considered technologically feasible if the protective measures it requires already exist, can be brought into existence with available technology, or can be created with technology that can reasonably be expected to be developed (see

American Iron and Steel Institute

OSHA (Lead II),

939 F.2d 975, 980 (D.C. Cir. 1991)). A standard is economically feasible when industry can absorb or pass on the costs of compliance without threatening the industry's long-term profitability or competitive structure (see

American Textile Mfrs. Institute

OSHA (Cotton Dust),

452 U.S. 490, 530 n. 55 (1981); Lead II, 939 F.2d at 980). A standard is cost effective if the protective measures it requires are the least costly of the available alternatives that achieve the same level of protection (see LOTO II, 37 F.3d at 668).

All OSHA standards must be highly protective (LOTO II, 37 F.3d at 669) and, where practical, “expressed in terms of objective criteria and of the performance desired.” 29 U.S.C. 655(b)(5). Finally, the OSH Act requires that when promulgating a rule that differs substantially from a national consensus standard, OSHA must explain why the promulgated rule is a better method for effectuating the purpose of the OSH Act. 29 U.S.C. 655(b)(8). As discussed earlier, OSHA is using NFPA 70E as the basis for its final rule, with some modifications as necessary, as explained in detail in the next section of the preamble.

V. Summary and Explanation of the Final Standard

This section discusses the important elements of the final standard, explains the purpose of the individual requirements, and explains any differences between the final standard and the existing standard. This section also discusses and resolves issues raised during the comment period, significant comments received as part of the rulemaking record, and any substantive changes that were made from the language of the proposed rule. References in parentheses are to exhibits in the rulemaking record. Except as noted, OSHA is carrying forward the language from the proposal into the final rule without substantive differences.

A. Issues

Comments supporting the revision of Subpart S.

The vast majority of the comments supported OSHA's efforts to update the general industry electrical standards (Exs. 3-3, 3-4, 3-6, 3-7, 3-8, 3-9, 4-10, 4-24). For example, the National Petrochemical & Refiners Association expressed support for updating Subpart S so that it is consistent with the current editions of the NFPA 70E and the NEC, because, they stated, its members place a high priority on safety and understand the necessity for electrical installation standards (Ex. 3-4). The American Society of Safety Engineers (ASSE) also supported the proposal, stating: “It is appropriate to move forward with this revision, given the seriousness of electrical hazards and the fact that nearly 300 workers are killed each year from contact with electrical current or as the result of injuries caused by fires and explosions related to electrical accidents [Ex. 3-5].”

The National Institute for Occupational Safety and Health (NIOSH) and the North Carolina Department of Labor also supported OSHA's proposed revision (Exs. 3-9, 5-2). NIOSH stated: “The proposed revised standard will provide workers in general industry and maritime employment with improved protection against injuries and death from electrical hazards [Ex. 3-9].” The North Carolina Department of Labor expressed a similar view, stating: “The revisions proposed to the existing standard should provide a greater measure of protection to employees working on and around electrical equipment and installations [Ex. 5-2].”

OSHA appreciates the support of these commenters. The Agency believes that the final standard will better protect employees than the existing standard. The record overwhelmingly supports this view.

OSHA should use the latest version of NFPA 70E or the NEC.

OSHA received several comments recommending that the standard be based on the latest version of NFPA 70E or the NEC (Exs. 3-8, 4-3, 4-6, 4-8, 4-11). Some of the commenters argued that, by using the 2000 edition of the NFPA 70E rather than the more recent 2004 edition, OSHA was not reflecting the most current practices and technology. For example, David Soffrin of the American Petroleum Institute stated:

We applaud the reasons for the proposal, as stated by OSHA: (a) To reflect the most current practice and technology in the industry; and (b) to respond to requests from stakeholders that the electrical standards conform with the most recent editions of the National Fire Protection Association (NFPA) 70E, Standard for Electrical Safety Requirements for Employee Workplaces, and the National Electrical Code (NEC). However, the proposal follows the NFPA standard 70E-2000, while the NFPA Standards Council issued an updated version January 14, 2004, which supercedes NFPA 70E-2000. We believe that if the intent is to reflect the most current practice and technology, using a four-year-old standard, which will be even more dated by the time OSHA finalizes this standard, is inappropriate. We therefore recommend that OSHA revise the proposal using NFPA 70E-2004, Standard for Electrical Safety in the Workplace, or the 2002 NEC, which would require numerous modifications [Ex. 4-11].

John Paschal of the Bechtel Corporation wrote: “Since NFPA 70E-2004 is now published and issued to the public, and since it contains significantly enhanced technical data that the NFPA 70E-2000 did not contain, I recommend that OSHA adopt NFPA 70E-2004 instead of NFPA 70E-2000 [Ex. 4-3].”

James Kendrick of ASSE noted that the major differences between the current versions of the OSHA electrical installation standards and the proposed rule fall into the following categories:

• Changes in the hardware specifications that are consistent with NEC requirements,

• Changes in installation practices that are consistent with the current, accepted installation practices followed by licensed electricians and other qualified persons,

• Clarification of existing requirements that add minimal new obligations or otherwise permit flexibility in compliance, and

• Requirements that do significantly modify electrical system and equipment installation practices or impose new documentation requirements (Ex. 3-5).

He was concerned that the OSHA final rule would be functionally obsolete when it is published and, thus, have diminished utility in the future since most electricians are currently learning the NEC 2002 coding system. He argued that it would be beneficial for OSHA to use the same standard as those involved in electrical work.

OSHA has decided not to base the final rule as a whole on NFPA 70E-2004, which was published on April 9, 2004, shortly after OSHA's proposal was published. The 2004 version of the national consensus standard was not placed in the rulemaking record; therefore, the Agency does not believe that the public would have had adequate notice of the many changes in the latest NFPA standard, to the extent that the Agency would have incorporated these changes in the final rule. Basing Subpart S on the latest edition of NFPA 70E would thus necessitate reproposing the rule. Given the time involved in reproposing and finalizing an OSHA standard, it is likely that NFPA 70E will be revised yet again within that timeframe. In addition, because NFPA 70E and OSHA's electrical installation standard were developed specifically to minimize the need for revision with every new version of the NEC, a final rule based on the 2000 edition of NFPA 70E will not be obsolete. Furthermore, several provisions in the final rule are based on corresponding requirements in the 2002 NEC, on which NFPA 70E-2004 is based. (See the distribution table later in this section of the preamble.) In proposing and finalizing this revision of Subpart S, OSHA carefully chose which NEC changes would have the greatest impact on employee safety. The Agency does not believe that delaying the substantial increase in employee safety that would result from the standard published in the final rule is warranted.

On the other hand, where the rulemaking record supports specific requirements that are consistent with the 2004 edition of NFPA 70E, OSHA has adopted those requirements in the final rule. For example, final § 1910.304(b)(3)(ii)(A) is based, in part, on Section 410.4(B)(1) of the 2004 edition of NFPA 70E rather than Part I, Chapter 2, Section 2.4 of the 2000 edition of NFPA 70E. (See the detailed explanation, later in the preamble, discussing the rationale for this provision, which requires a written assured equipment grounding conductor program where ground-fault circuit-interrupters are not available.) In these specific cases, the rulemaking record supports OSHA's using the language from the relevant provision in NFPA 70E-2004 and from the 2002 NEC, on which the new NFPA 70E requirement is based. This avoids the notice problem discussed earlier. In addition, OSHA will consider using later versions of NFPA 70E to update the electrical installation requirements adopted in this final rule when the Agency develops future proposals to revise Subpart S to update the existing electrical safety-related work practice requirements and to adopt new provisions on safety-related maintenance and special equipment.

OSHA should update the Electrical Standard for construction at the same time this rule is being promulgated.

The Agency received one comment asking OSHA to consider revising the Electrical Standard for construction at the same time as the revision to the Electrical Standard for general industry (Ex. 4-2). Reliable Safety Solutions, LLC, stated that installing equipment in general industry and installing equipment in the construction industry is much the same (Ex. 4-2). They argued that the hazards encountered are the same and the safe work practices when working with electricity are the same. Thus, they said that to update one standard and not the other would allow for one standard to be out of date and certain hazards to exist.

The Agency is aware that the general industry and the construction industry both address similar electrical hazards and have similar safe work practices. OSHA is also aware that its electrical standards for construction in 29 CFR 1926, Subpart K also need updating. Like Subpart S, Subpart K is based on the 1979 edition of NFPA 70E. In addition, the electrical safety-related work practices in Subpart K are even older than their general industry counterparts. However, OSHA must consult with the Advisory Committee on Construction Safety and Health before publishing a proposal. In addition, OSHA would have to include the construction industry in its regulatory analysis and repropose the standard to address construction as part of this rulemaking. Although OSHA will consider updating Subpart K to make it consistent with Subpart S in the future, it is not possible to do so as part of this final rule.

OSHA should update the safety-related work practice requirements in Subpart S at the same time this rule is being promulgated.

One commenter recommended that OSHA revise its electrical safety-related work practice standard in Subpart S based on the corresponding requirements in NFPA 70E (Ex. 4-5). He argued that electricians encounter exposed energized parts of electric circuits, which demonstrates the need for the protective clothing and safe work practices contained in NFPA 70E.

OSHA agrees that the latest editions of NFPA 70E provide improved protection to employees through better electrical safety-related work practices. In particular, the heightened focus on the hazards posed by electric arcs may substantially reduce injuries and fatalities associated with those hazards. However, revising the safety-related work practice requirements in Subpart S is beyond the scope of this rulemaking. The Agency is planning to update these requirements as the next phase of the project to update OSHA's electrical standards. Although OSHA expects this phase of the project to yield significant benefits, the Agency also expects it to take longer to promulgate a final rule on safety-related work practices owing to the more complex regulatory analysis required and the greater controversy that is likely to be encountered.

B. Scope

Existing §§ 1910.302 through 1910.308 of Subpart S apply to electrical installations and utilization equipment used and installed in workplaces in general industry and in shipyard employment, longshoring, and marine terminals. These sections do not apply to the following types of installations:

(1) Installations in ships, watercraft, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles;

(2) Installations underground in mines;

This exception was incorporated into the current OSHA standard to be consistent with language used in the NEC and NFPA 70E. However, it should be noted that OSHA does not have jurisdiction over mines in general, regardless of whether the mining activity takes place above ground or underground. Under the Mine Safety and Health Act (MSH Act) (30 U.S.C. 801

et seq.

), the Mine Safety and Health Administration (MSHA) regulates safety and health in mines. For further information, see the Interagency Agreement between MSHA and OSHA (

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=MOU&p_id=222

(3) Installations of railways for generation, transformation, transmission, or distribution of power used exclusively for operation of rolling stock or installations used exclusively for signaling and communication purposes;

(4) Installations of communication equipment under the exclusive control of communication utilities and located outdoors or in building spaces used exclusively for such installations; and

(5) Installations under the exclusive control of electric utilities for the purpose of communication or metering; or for the generation, control, transformation, transmission, and distribution of electric energy. These exempted installations must be located in buildings used exclusively by utilities for such purposes or located outdoors on property owned or leased

by the utility or on public highways, streets, roads, etc., or outdoors by established rights on private property.

These exempted installations present special design considerations that are not adequately addressed in Subpart S. For example, electric power transmission and distribution installations are typically installed where unqualified persons will not have access to them, and the only employees working on them are highly trained and skilled. Additionally, public safety considerations demand that these installations be capable of quick repair when weather or equipment failure disrupts electrical service. The National Electrical Safety Code (ANSI/IEEE C2), which is developed by experts in electric power generation, transmission, and distribution, contains design and installation requirements applicable to electric power generation, transmission, and distribution systems. Section 1910.269 contains OSHA's standard for the maintenance of electric power generation, transmission, and distribution installations. While it consists mostly of work-practice requirements, it does contain several installation requirements. For example, § 1910.269(u)(4) and (v)(4) cover guarding of rooms containing electric supply equipment in electric power generating stations and substations, respectively.

Installations in ships, watercraft, railway rolling stock, aircraft, or automotive vehicles (other than mobile homes and recreational vehicles) are designed to be transportable.

These transportability considerations make many of the design requirements in Subpart S irrelevant or infeasible. For example, attaching the grounded circuit conductor and the equipment grounding conductor to a permanent grounding electrode on a transportable wiring system is generally not feasible. Thus, some of the provisions in final § 1910.304(g), which contains requirements for grounding electrical systems, are inappropriate for the wiring of ships, watercraft, railway rolling stock, aircraft, or automotive vehicles. By contrast, however, wiring that is not a part of the wiring of the ship, watercraft, railway rolling stock, aircraft, or automotive vehicle would be covered by Subpart S, as appropriate. For example, a portable electric drill carried into the cargo area of a truck would be covered by Subpart S if it is plugged into the wiring of a service station.

Although the wiring of recreational vehicles and mobile homes is transportable, it is also designed to be attached to specially designed, permanently installed power distribution outlets. This type of hybrid system must be designed for both permanent and transportable uses.

In regard to ships, there has been some confusion about whether the “exemption” applies to all wiring or electrical installations brought on board a vessel during construction, repair, or ship scrapping even when the wiring is supplied by shore-based electric power—or whether it only applies to the ship's own wiring. OSHA is hereby clarifying the application of the exemptions.

The “exempted” types of installations in both the existing and final standards are identical to those “exempted” by the NEC and NFPA 70E, which form the basis of both standards. Installations covered under the existing standard continue to be covered under the final standard. For example, in longshoring operations and related employments, this final rule applies to electrical installations aboard vessels only if they are shore-based as stated in § 1918.1(b)(3). Electrical installations in marine terminals are also covered under Subpart S, as noted in § 1917.1(a)(2)(iv). (The marine terminals standard in Part 1917 applies to the loading, unloading, movement or other handling of cargo, ship's stores or gear within the terminal or into or out of any land carrier, holding or consolidation area, and any other activity within and associated with the overall operation and function of the terminal. This includes the use and routine maintenance of facilities and equipment and cargo transfer accomplished with the use of shore-based material handling devices. See § 1917.1(a).)

Section 1910.5 governs how the general industry standards apply to shipyard employment. According to § 1910.5(c), the general standards in Part 1910 apply to shipyard employment to the extent that no industry-specific standard applies to the “same condition, practice, means, method, operation, or process.” Part 1915 contains few requirements related to electrical safety. Paragraph (b) of § 1915.93 contains four such requirements, for grounding of vessels, the safety of the vessel's wiring, overcurrent protection, and guarding of infrared heat lamps. Section 1915.92 contains provisions on temporary electric lighting, and § 1915.132 contains requirements on portable electric tools. Section 1915.181 contains electrical safety-related work practices for deenergizing electric circuits and protecting employees against contact with live parts during electrical work. In addition, Part 1915 contains several other miscellaneous electrical safety-related work practices and electrical design requirements. These provisions continue to apply in lieu of any corresponding requirements in Subpart S of Part 1910. Conversely, where there is no specific electrical installation requirement for shipyard employment in Part 1915, Subpart S of Part 1910 applies.

As noted earlier, Subpart S does not cover installations in ships, but it does cover installations used on ships if the installation is shore-based (that is, not part of the vessel's original, internal electrical system). Thus, final § 1910.303(g)(2) (guarding live parts) applies to the shore-based wiring of the shipyard and to any wiring taken onto the ship when it is supplied by shore-based wiring. It does

not

apply to the ship's permanent wiring. The final rule does not change this coverage.

C. Grandfather Clause

The final rule, as does the current standard, exempts older electrical installations from meeting some of the provisions of the Design Safety Standards for Electrical Systems (that is, §§ 1910.302 through 1910.308). The extent to which OSHA's electrical installation standard applies depends on the date the installation was made. Older installations must meet fewer requirements than newer ones. The grandfathering of older installations, contained in paragraph (b) of final § 1910.302, is patterned after the current standard's grandfather provisions in existing § 1910.302(b). Most of the new provisions contained in the final rule only apply prospectively, to installations made after the effective date of the final rule.

The following paragraphs explain final § 1910.302(b) in the following order: Paragraph (b)(1), requirements applicable to all installations; paragraph (b)(4), requirements applicable only to installations made after the effective date of the revised standard; paragraph (b)(3), requirements applicable only to installations made after April 16, 1981; and paragraph (b)(2), requirements applicable only to installations made after March 15, 1972.

Requirements applicable to all installations.

Paragraph (b)(1) of final § 1910.302 contains a list of provisions that would apply to all installations, regardless of when they were designed or installed. The few requirements in this short list are so essential to employee safety that even the oldest electrical installations must be modified, if necessary, to meet them. The list is unchanged from the current standard, except for the addition of: a prohibition on using grounding terminals and devices for purposes other than grounding (in final

§ 1910.304(a)(3)); a documentation requirement for hazardous locations made under the zone classification system (in final § 1910.307(b)); and requirements covering the zone classification system (in final § 1910.307(g)).

New provisions applicable to all installations.

Paragraph (a)(3) of § 1910.304 prohibits the use of a grounding terminal or grounding-type device on a receptacle, cord connector, or attachment plug for purposes other than grounding. OSHA's reasons for adding this requirement to the list of provisions applicable to all installations is discussed later in this section of the preamble.

Paragraph (b) of final § 1910.307 contains a new requirement that employers document areas designated as hazardous (classified) locations. This requirement would ensure that the employer has records of the extent and classification of each such area. The documentation will help employers to determine what type of equipment is needed in these locations and will inform employees of the need for special care in the maintenance of the electric equipment installed there. OSHA has carefully considered the need to document these areas and has tried to balance that need with the extensive burden that would be placed on employers who would have to survey and document their existing hazardous locations.

The current standard's division classification system has been in place for many years, and most employers and inspection authorities are familiar with the boundaries for Class I, II, and III, Division 1 and 2 locations. An employee servicing equipment in one of these locations can obtain this information relatively easily even if the employer has not documented the boundaries. Accordingly, OSHA believes that the benefit of documenting existing hazardous locations installed using the division classification system would be minimal. Therefore, for employers using the division system, OSHA is requiring documentation of boundaries only for new installations made after the effective date of the final standard. Employers would not need to document existing division-classified systems.

On the other hand, the zone classification system is relatively new. Most employers are not familiar with this system and have little experience determining how to draw the boundaries between the three zones. Relatively few NFPA or industry standards provide specifications for placing those boundaries. Furthermore, the existing OSHA electrical standard recognizes only installations made in accordance with the division classification system, not the zone classification system. Any existing installation made under the zone system is technically out of compliance with OSHA's existing standard. However, because the NEC represents standard industry practice, existing zone system installations will almost certainly have been installed in accordance with an edition of the NEC that recognizes the zone classification system (the 1999 and 2002 editions). These editions of the NEC explicitly require documentation of hazardous locations. Thus, an employer with an existing installation made under the zone classification system should already have the documentation required by final § 1910.307(b). For these reasons, OSHA is applying the documentation requirement to all hazardous location installations made under the zone classification system. This will provide employers, employees, and OSHA with information critical for determining which equipment is suitable in a given hazardous location.

The new requirements pertaining to zone classification in final § 1910.307(g) provide employers with an alternative installation method that the current standard does not permit.

Thus, applying these provisions to older installations would give employers greater flexibility without imposing any new costs. Furthermore, to the extent that employers are already using the zone classification system, those employers are likely already meeting final § 1910.307(g), which is based on provisions in the 1999 and 2002 editions of the NEC.

See the discussion under the heading “Zone Classification” for an explanation of the zone classification system and its differences from the current standard's division classification system.

Requirements applicable only to installations made after the effective date of the final rule.

Paragraph (b)(4) of final § 1910.302 makes the following provisions applicable only to installations made or overhauled

after the effective date of the final rule:

See the discussion of the term “overhaul” later in this section of the preamble.

§ 1910.303(f)(4)

Disconnecting means and circuits—Capable of accepting a lock.

§ 1910.303(f)(5)

Disconnecting means and circuits—Marking for series combination ratings.

§ 1910.303(g)(1)(iv) and (g)(1)(vii)

600 Volts, nominal, or less—Space about electric equipment.

§ 1910.303(h)(5)(vi)

Over 600 volts, nominal—Working space and guarding.

§ 1910.304(b)(1)

Branch circuits—Identification of multiwire branch circuits.

§ 1910.304(b)(3)(i)

Branch circuits—Ground-fault circuit interrupter protection for personnel.

§ 1910.304(f)(2)(i)(A), (f)(2)(i)(B) (but not the introductory text to § 1910.304(f)(2)(i)), and (f)(2)(iv)(A)

Overcurrent protection—Feeders and branch circuits for over 600 volts, nominal.

§ 1910.305(c)(3)(ii)

Switches—Connection of switches.

§ 1910.305(c)(5)

Switches—Grounding.

§ 1910.306(a)(1)(ii)

Electric signs and outline lighting—Disconnecting means.

§ 1910.306(c)(4)

Elevators, dumbwaiters, escalators, moving walks, wheelchair lifts, and stairway chair lifts—Operation.

§ 1910.306(c)(5)

Elevators, dumbwaiters, escalators, moving walks, wheelchair lifts, and stairway chair lifts—Location.

§ 1910.306(c)(6)

Elevators, dumbwaiters, escalators, moving walks, wheelchair lifts, and stairway chair lifts—Identification and signs.

§ 1910.306(c)(7)

Elevators, dumbwaiters, escalators, moving walks, wheelchair lifts, and stairway chair lifts—Single-car and multicar installations.

§ 1910.306(j)(1)(iii)

Swimming pools, fountains, and similar installations—Receptacles.

§ 1910.306(k)

Carnivals, circuses, fairs, and similar events.

§ 1910.308(a)(5)(v) and (a)(5)(vi)(B)

Systems over 600 volts, nominal—Interrupting and isolating devices.

§ 1910.308(a)(7)(vi)

Systems over 600 volts, nominal—Tunnel installations.

§ 1910.308(b)(3)

Emergency power systems—Signs.

§ 1910.308(c)(3)

Class 1, Class 2, and Class 3 remote control, signaling, and power-limited circuits—Separation from conductors of other circuits.

§ 1910.308(f)

Solar photovoltaic systems.

These provisions are based on requirements that have been added to the NEC since the 1978 edition. OSHA has never required employers to comply with these requirements, and the Agency believes that an increase in employee protection will result from compliance with them in new installations. At the same time, employers would incur minimal costs to achieve this increase in new installations. In local jurisdictions requiring compliance with the NEC, there should be no additional costs involved, because the installations would already conform to the new OSHA requirements. The Agency believes that even in other jurisdictions, the vast majority of installations already comply with the latest edition of the NEC, because compliance with the latest Code is standard industry practice. OSHA, however, does not believe that it is reasonably necessary and appropriate to require existing installations to conform to these provisions, particularly given the cost and difficulty associated with retrofitting older installations.

There are many provisions in the final rule that are not contained in the existing standard but cannot be considered totally “new” provisions. Most of these “new” requirements were actually contained in the 1971 NEC. Table 1 lists these “new” provisions and denotes their counterparts in the 1971 NEC. From March 15, 1972, until April 16, 1981, Subpart S incorporated the 1971 NEC by reference in its entirety. Accordingly, OSHA required employers to comply with every requirement in the 1971 NEC for any new installation made between those dates and for any replacement, modification, repair, or rehabilitation made during that period. The current standard, which became effective on April 16, 1981, omitted many of the detailed provisions of the NEC because they were already addressed by the more general requirements that were contained in the OSHA standard. For example, OSHA did not carry forward 1971 NEC Section 110-11, which required equipment to be suitable for the environment if it is installed where the environment could cause deterioration. However, the requirement for equipment to be suitable for the location in which it was installed is implicit in the more general requirements in existing § 1910.303(a) that equipment be approved and in existing § 1910.303(b)(2) that equipment be installed in accordance with any instructions included in its listing or labeling. (Equipment that is not suitable for installation in deteriorating environments, such as wet or damp locations, will include instructions warning against such installation. These instructions are required by the nationally recognized testing laboratory listing or labeling the product.)

Even though OSHA no longer specifically incorporates the 1971 NEC into Subpart S, the Agency believes that employers’ installations actually do comply with those requirements. The vast majority of employers are following the entire NEC applicable to their installations, as noted in the Economic Analysis section of this preamble.

For these reasons, OSHA is not exempting installations made after March 15, 1972, from meeting any provision listed in Table 1 and is not including any of these provisions in final § 1910.302(b)(4) (the list of provisions that apply only to new installations).

All of the requirements in question appear in some form in every edition of the NEC since 1972.

These provisions have no direct counterpart in existing Subpart S, but were in the 1971 National Electrical Code.

Table 1.—“New” Provisions That Were Contained in 1971 NEC

Provision in the final standard

Equivalent 1971

NEC section

Subject

§ 1910.303(b)(3)

110-20

Insulation integrity.

(b)(4)

110-9

Interrupting rating.

(b)(5)

10-10

Circuit impedance and other characteristics.

(b)(6)

110-11

Deteriorating agents.

(b)(7)

110-12

Mechanical execution of work.

(b)(8)

110-4(a) and (d)

110-12

110-13

Mounting and cooling of equipment.

(c)(1)

110-14

Electrical connections, general.

§ 1910.304(b)(2)

210-21(b)

Branch circuits, receptacles and cord connectors.

(b)(4)

210-21

Branch circuits, outlet devices.

(b)(5)

210-22

Branch circuits, cord connections.

(e)(1)(iii)

230-70(c)

Services, disconnecting means.

(f)(1)(ix)

110-9

240-11

Overcurrent protection, 600 volts, nominal, or less, circuit breaker ratings.

(f)(2), except for (f)(2)(i)(A), (f)(2)(i)(B), and (f)(2)(iv)(A)

240-5

240-11

240-15

Overcurrent protection, feeders and branch circuits over 600 volts, nominal.

§ 190.305(a)(4)(ii)

320-5

Open wiring on insulators, support.

(b)(1)(iii)

370-7

373-5

Conductors entering cabinets, boxes, and fittings, securing conductors.

(b)(2)(ii)

370-15(b)

Fixture canopy or pan installed in a combustible wall or ceiling.

(e)(1)

373-2

384-5

Airspace for enclosures installed in wet or damp locations.

(h)(3)

710-6

Portable cables, grounding conductors.

(j)(2)(i)

410-52(d)

Receptacles, cord connectors, and attachment plugs; no exposed energized parts.

(j)(2)(iv) through (j)(2)(vii)

410-54

Receptacles installed in wet or damp locations.

(j)(3)(ii)

422-20

Appliances, disconnecting means.

(j)(3)(iii)

422-30(a)

Appliances, nameplates.

(j)(3)(iv)

422-30(b)

Appliances, marking to be visible after installation.

(j)(6)(ii)(A)

110-9

110-10

460-8(c)(4)

Capacitor switches.

(j)(6)(ii)(B)

460-8(c)(1)

Capacitor disconnecting means.

§ 1910.306(c)(3)

620-51(a)

Elevators, dumbwaiters, escalators, moving walks, wheelchair lifts, and stairway chair lifts; type of disconnecting means.

(c)(10)

620-72

Elevators, dumbwaiters, escalators, moving walks, wheelchair lifts, and stairway chair lifts; motor controllers.

(d)(1)

630-13

630-23

Arc welders, disconnecting means.

(g)(1)(iii)

665-34

Induction and dielectric heating equipment, detachable panels used for access to live parts.

(g)(1)(vi)

665-8

Induction and dielectric heating equipment, ampere rating of disconnecting means.

(j)(4)(iii)

680-20(a)(4)

Swimming pools, fountains, and similar installations, underwater fixtures facing upwards.

§ 1910.308(a)(2)

710-4

Systems over 600 volts, nominal; open installations of braid-covered insulated conductors.

(a)(3)(i)

710-6

Systems over 600 volts, nominal; insulation shielding terminations.

(a)(4)

710-8

Systems over 600 volts, nominal; moisture or mechanical protection for metal-sheathed cables.

(a)(5)(i)

710-21(a)

Systems over 600 volts, nominal; interrupting and isolating devices; guarding and indicating.

(a)(5)(ii)

240-11(a)

710-21(b)

Systems over 600 volts, nominal; interrupting and isolating devices; fuses.

(a)(5)(iii) and (a)(5)(iv)

710-21(b)

Systems over 600 volts, nominal; interrupting and isolating devices; fused cutouts.

(a)(5)(vi), but not (a)(5)(vi)(B)

710-21(c)

Systems over 600 volts, nominal; interrupting and isolating devices; load interrupter switches.

(a)(5)(vii)

710-22

Systems over 600 volts, nominal; interrupting and isolating devices; means for isolating equipment.

(b)(2)

700-14

Emergency systems, emergency illumination.

In addition, OSHA is not including in the list of new provisions in final § 1910.302(b)(4) any provision that merely provides an alternative means of compliance for an existing requirement. For example, as noted earlier, final § 1910.307(g) provides alternative requirements for installations in hazardous (classified) locations based on the zone classification system rather than the division classification system that is required under the existing standard. Such requirements accept alternative installation techniques recognized as being equally protective by the NEC and NFPA 70E, and there is no need to limit them to new installations.

OSHA also believes that there is no need to grandfather requirements that apply only to temporarily installed equipment and wiring.

The few new requirements applying to temporarily installed equipment and wiring have been in the NEC since at least 1999 and, in most cases, since before that. Employers should already be in compliance with such requirements since any existing temporary installations almost certainly were put into place well after 1999.

For example, final § 1910.304(b)(3)(ii) contains requirements for providing ground-fault circuit interrupter protection for temporary wiring installations that are used during maintenance, remodeling, or repair of buildings, structures, or equipment or during similar activities. Temporary wiring installations used for any of these purposes were likely to have been installed well after 1999. An employer who is complying with the 1999 or later edition of the NEC will already be complying with this provision of the rule. Even employers who are not complying with recent versions of the NEC for temporary wiring installations will face, in this example, only the minimal cost of providing ground-fault circuit interrupters; no changes would need to be made to any existing permanent wiring, which might involve considerably more costs.

For the purposes of this discussion, “temporarily installed equipment or wiring” is wiring and equipment installed on a short-term rather than a long-term or permanent basis. It includes temporary wiring covered by proposed § 1910.305(a)(2) and other equipment and wiring similarly installed on a short-term basis.

The limit for temporary wiring used for Christmas decorative lighting, carnivals, and similar purposes is 90 days (§ 1910.305(a)(2)(i)(B)). For other purposes, such as remodeling and repair, the limit is the duration of the activity. However, OSHA believes that it is highly unlikely that any particular temporary activity covered by Subpart S has been on-going since 1999.

Requirements applicable only to installations made after April 16, 1981.

Paragraph (b)(3) of final § 1910.302 lists requirements that apply only to installations made after April 16, 1981.

This paragraph carries forward essentially the same list as is currently in § 1910.302(b)(3). No provisions have been added to or removed from the list.

Requirements applicable only to installations made after March 15, 1972.

Paragraph (b)(2) of existing § 1910.302 requires all installations made after March 15, 1972, and every major replacement, modification, repair, or rehabilitation made after that date to meet all the installation requirements in Subpart S except for those listed in existing § 1910.302(b)(3). A note following existing § 1910.302(b)(2) indicates that “ ‘[m]ajor replacements, modifications, repairs, or rehabilitations’ include work similar to that involved when a new building or facility is built, a new wing is added, or an entire floor is renovated.”

Paragraph (b)(2) of final § 1910.302 will require all installations built or overhauled after March 15, 1972, to comply with all of the requirements of final §§ 1910.302 through 1910.308, except as provided in final § 1910.302(b)(3) and (b)(4). As discussed earlier, these latter two paragraphs limit the application of newer provisions of Subpart S to installations made during later periods.

In § 1910.302(b)(2) in the final rule, OSHA is introducing the term “overhaul” to include the types of activities that would trigger compliance with the otherwise grandfathered provisions of Subpart S for older installations. In § 1910.399 of the final rule, “overhaul” is defined as follows:

Overhaul

means to perform a major replacement, modification, repair, or rehabilitation similar to that involved when a new building or facility is built, a new wing is added, or an entire floor is renovated.

This new term incorporates all the elements of “major replacement, modification, or rehabilitation” in the text of existing § 1910.302(b)(2) and in the note following that provision. OSHA believes that using and defining the term “overhaul” in the final rule will simplify the standard without making any substantive change to the way in which Subpart S applies to older installations.

Comments on the grandfather clause.

OSHA received several comments on the grandfather clause proposed in § 1910.302(b) (Exs. 3-7, 4-25). One commenter was concerned about the level of cross-referring an employer would need to do to determine what standards are applicable to a given installation (Ex. 3-7). He recommended that a simpler approach be adopted or that OSHA develop guidance materials to help employers determine which requirements apply to installations made during each of the periods addressed by the grandfather clause. Neither commenter proposed language that might accomplish this.

While OSHA acknowledges that some commenters believe that this clause is too complex, the Agency believes that the approach taken in the final standard is as simple as the Agency can make it. However, OSHA will provide compliance assistance tools that will help employers understand which requirements are applicable to their particular electrical installations. For example, the Agency is considering providing on the OSHA Website a color-coded version depicting requirements with different applicability dates with different colors or a version that lets the reader input the date of the installation and that hides inapplicable provisions. Such tools should enable employers to determine their compliance obligations quickly and easily. In addition, for questions about compliance with the standard, employers can contact OSHA through its toll-free telephone help line at 1-800-321-6742. Alternatively, employers can contact the OSHA Area Office or State Plan office nearest them.

Paragraph (b)(4) of final § 1910.302 lists § 1910.304(b)(3)(i) (proposed § 1910.304(b)(4)(i)), which requires ground-fault circuit interrupter protection for certain permanently installed receptacle outlets, as a provision that only applies to new installations. One commenter recommended that all of proposed § 1910.304(b)(4), which as noted previously contains requirements for ground-fault circuit interrupters on temporary receptacle outlets, apply only to new installations (Ex. 3-7). The commenter noted that this provision is new and should only be applied to new installations.

As noted earlier, OSHA believes that most employers are already complying with this provision. The National Electrical Code has required ground-fault circuit interrupters in a manner similar to that in the final rule since the 1996 edition of the NEC. In addition, the final rule sets an effective date 180 days after publication of the final rule in the

Federal Register

. OSHA believes that very few temporary installations that were in place before publication of the final rule will still be in place 6 months later. There may be some projects using temporary wiring that last more than 6 months, particularly in shipyards. However, even there, OSHA believes that temporary receptacle outlets will be moved around, installed, uninstalled, and reinstalled many times over the life of the project. Even if the Agency were to apply final § 1910.304(b)(3)(ii) only to installations made after the effective date, it would apply as soon as a receptacle outlet was installed (or reinstalled). OSHA does not believe that there is a compelling reason to exempt the very few remaining temporary receptacle outlets that may still be in place after the effective date. Therefore, OSHA has not adopted the commenter's recommendation.

Mr. Pat Kimmet of CHS Inc. and Mr. Rick Leicht of NCRA were concerned that provisions listed in proposed § 1910.302(b)(1), which were to apply to all installations regardless of age, would require employers to examine existing installations for compliance and possibly replace noncompliant equipment even when no significant hazard exists (Ex. 4-25). They specifically objected to the inclusion of wire bending space (proposed § 1910.303(b)(1)(iii)) on the list. They argued that this provision is a relatively recent addition to the NEC and that the NEC has revised the wire bending space requirements periodically. They believed that the proposal would have required employers to meet the wire bending space requirements in the 2000 edition of the NFPA 70E and the 2002 edition of the NEC.

OSHA believes that an installation that does not comply with the provisions listed in final § 1910.302(b)(1) poses a significant hazard to employees. Furthermore, as noted earlier, almost all of the provisions listed in that paragraph applied to all installations regardless of age since March 15, 1972. Thus, employers should already be in compliance with nearly all of the listed provisions.

The new provisions related to the zone classification system (including the documentation requirement) provide for an alternative compliance method to that required by the existing standard. The other new provision, the prohibition on using grounding terminals and devices for purposes other than grounding, as noted earlier, has been a long-standing NEC requirement. Thus, OSHA does not believe that very many existing installations are in violation of this new provision. Consequently, Mr. Kimmet's and Mr. Leicht's general concerns about widespread noncompliance are unfounded.

With respect to their specific concern with the inclusion of proposed § 1910.303(b)(1)(iii) in the list of provisions applicable to all installations, OSHA notes that wire bending space, as mentioned in this provision, is simply one of several

factors to be considered in judging electrical equipment for safety. Paragraph (b)(1) of final § 1910.303 reads, in part, as follows:

(b)

Examination, installation, and use of equipment.

(1)

Examination.

Electric equipment shall be free from recognized hazards that are likely to cause death or serious physical harm to employees. Safety of equipment shall be determined using the following considerations:

(iii) Wire-bending and connection space;

(viii) Other factors that contribute to the practical safeguarding of persons using or likely to come in contact with the equipment.

Paragraph (b)(1)(iii) of final § 1910.303 does not require compliance with the minimum wire bending space requirements in the NEC. Rather, wire bending space will be one of the relevant factors in judging the electrical safety of equipment in accordance with the introductory text of final § 1910.303(b)(1). OSHA does not consider this a new requirement. The current standard contains the catchall “other factors” language in existing § 1910.303(b)(1)(vii). The Agency construes wire bending space to be one of those “other factors” judged under the existing standard. Thus, OSHA is simply making explicit in the final rule a factor employers were required to consider under § 1910.303(b)(1)(vii) of the existing standard. If conductors are installed so tightly into enclosures that they overheat or that the insulation is damaged, a serious safety hazard would exist. Such an installation would violate the existing standard as well as the new one. For these reasons, OSHA has not adopted Mr. Kimmet's and Mr. Leicht's recommendation to remove § 1910.303(b)(1)(iii) from the list of provisions in final § 1910.302(b)(1) that apply to all installations.

Several commenters suggested that proposed § 1910.304(a)(3) be added to the list of requirements in § 1910.302(b)(1) applicable to all installations (Exs. 4-13, 4-17, 4-18, 4-21). Proposed § 1910.304(a)(3) read as follows:

A grounding terminal or grounding-type device on a receptacle, cord connector, or attachment plug may not be used for purposes other than grounding.

Mr. Bernie Ruffenach typified these commenters, reasoning as follows:

The use of the grounding terminal(s) of any device has never been permitted in any electrical standards, codes or other recognized practices at any time. Typically, the use of the grounding terminal for other than grounding purposes is due to improper wiring and occurs when an ungrounded (hot) conductor is applied. The result is an imminent danger electrocution hazard. [Ex. 4-17]

OSHA agrees that using a grounding terminal or device for purposes other than grounding can present a hazard threatening imminent death or serious injury. For example, using a grounding terminal as the attachment point for a circuit conductor can energize the frame of equipment used by employees. If an employee was to touch such miswired equipment and a grounded surface at the same time, he or she would receive an electric shock and possibly die of electrocution. As the commenters noted, compliance with this provision has been a long-standing common industry practice. Therefore, OSHA has adopted the suggestion of these commenters and has added § 1910.304(a)(3) to the list of provisions in final § 1910.302(b)(1) that are applicable to all installations.

D. Applicability of Requirements for Disconnecting Means

Several provisions in the final standard require electrical disconnecting means to be capable of being locked in the open position under certain conditions. For example, final § 1910.306(a)(2)(i) requires the disconnecting means for sign and outline lighting systems to be capable of being locked in the open position if they are out of the line of sight from any section that may be energized. These provisions ensure that employees servicing or maintaining the electric circuits supplied by the disconnecting means are protected against electric shock.

Sometimes, these disconnecting means also serve as energy isolating devices as defined in paragraph (b) of § 1910.147, OSHA's existing standard for the control of hazardous energy sources (lockout-tagout). Energy isolating devices physically prevent the transmission or release of energy. In the case of electric equipment, disconnecting means that meet the definition of energy isolating devices prevent the transmission of electric energy so that the equipment cannot start up and injure employees.

Paragraph (c)(2)(iii) of the lockout-tagout standard reads as follows:

After January 2, 1990, whenever replacement or major repair, renovation or modification of a machine or equipment is performed, and whenever new machines or equipment are installed, energy isolating devices for such machine or equipment shall be designed to accept a lockout device.

Paragraph (c) of final § 1910.302 clarifies that the provision in the lockout-tagout standard is in addition to any requirements in Subpart S for disconnecting means to be capable of being locked open. The requirements in Subpart S are intended for the protection of servicing and maintenance employees from electric shock, which is not covered by § 1910.147. The lockout-tagout standard on the other hand addresses nonelectric-shock hazards related to servicing and maintaining equipment. Thus, the requirements of both standards are necessary to protect employees from all servicing- and maintenance-related hazards.

OSHA received no comments on this provision in the proposal, and it is being carried into the final rule without change.

E. Summary of Changes in §§ 1910.303 Through 1910.308

The Distribution Table for Subpart S lists all the provisions and sections from §§ 1910.303 through 1910.308. This table summarizes changes being made to the standard that involve grammatical edits, additions, removals, and paragraph numbers. There are places in the standard where no substantial change is made. Most of the changes are editorial in nature. Substantive changes made to the existing standard are discussed in further detail following the Distribution Table.

Distribution Table

OLD—section

NEW—section

Description of changes and rationale

See the note at the end of the table.

§ 1910.303 General

1910.303(a)

No substantive change. A reference to the § 1910.399 definition of “approved” is added for clarification.

1910.303(b)(1), introductory text

No substantive change.

1910.303(b)(1)(i)

No substantive change.

1910.303(b)(1)(ii)

No substantive change.

1910.303(b)(1)(iii)

**Adds wire-bending and connection space to the explicit list of things to consider when judging equipment.

1910.303(b)(1)(iii)

1910.303(b)(1)(iv)

No substantive change.

1910.303(b)(1)(iv)

1910.303(b)(1)(v)

No substantive change.

1910.303(b)(1)(v)

1910.303(b)(1)(vi)

No substantive change.

1910.303(b)(1)(vi)

1910.303(b)(1)(vii)

No substantive change.

1910.303(b)(1)(vii)

1910.303(b)(1)(viii)

No substantive change.

1910.303(b)(2)

No substantive change.

1910.303(b)(3)

**Adds a requirement for completed wiring to be free from short circuits and grounds other than those required in the standard.

1910.303(b)(4)

**Adds requirements for equipment intended to interrupt current to have adequate interrupting ratings.

1910.303(b)(5)

**Adds requirements for the coordination of overcurrent protection for circuits and equipment.

1910.303(b)(6)

**Adds a requirement for conductors and equipment to be identified for the purpose when installed in an environment containing deteriorating agents.

1910.303(b)(7)

**Adds requirements for installing electric equipment in a neat and workmanlike manner.

1910.303(b)(8)

**Adds requirements for equipment to be mounted securely and to allow for proper cooling.

1910.303(c)(1)

**Adds requirements to ensure that electrical connections are secure and electrically safe.

1910.303(c)(2)

**Adds requirements for connections at terminals and for the identification of terminals intended for connection to more than one conductor or to aluminum.

1910.303(c)

1910.303(c)(3)(i)

No substantive change.

1910.303(c)(3)(ii)

**Adds a requirement that wire connectors or splicing means installed on directly buried conductors be listed for such use.

1910.303(d)

No substantive change.

1910.303(e)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.303(f)

1910.303(f)(1), (f)(2), and (f)(3)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.303(f)(4)

Adds a requirement for disconnecting means required by Subpart S to be capable of accepting a lock. This provision is added to make the Subpart S requirements on disconnecting means consistent with § 1910.147(c)(2)(iii), which requires energy isolating devices (a generic term, which includes electrical disconnecting means) to be designed to accept a lockout device.

1910.303(f)(5)

**Adds marking requirements for series combination ratings of circuit breakers or fuses.

1910.303(g)(1), introductory text

No substantive change.

1910.303(g)(1)(i)

1910.303(g)(1)(i) Table S-1, Note 3

**The final rule revises the language to clarify how wide and high the clear space must be. (See detailed explanation later in the preamble).

1910.303(g)(1)(ii)

No substantive change.

1910.303(g)(1)(iii)

No substantive change.

1910.303(g)(1)(iv)

**Adds a requirement for a second entrance on equipment rated 1200 amperes under certain conditions.

1910.303(g)(1)(iv)

1910.303(g)(1)(i)(B)

**Reduces the minimum width of the clear space to 762 mm.

1910.303(g)(1)(v)

**Adds a prohibition against controlling illumination for working spaces by automatic means only.

1910.303(g)(1)(vi)

**Increased the minimum height of the working space from 1.91m to 1.98m for new installations.

1910.303(g)(1)(vii)

** Adds requirements for switchboards, panelboards, and distribution boards installed for the control of light and power circuits, and motor control centers to be installed in dedicated space and to be protected against damage.

1910.303(g)(2)

No substantive change.

1910.303(h)(1)

No substantive change.

1910.303(h)(2), introductory text

1910.303(h)(2)(i) and (h)(2)(ii)

**The minimum height of fences restricting access to electrical installations over 600 V is reduced from 2.44 m to 2.13 m.

1910.303(h)(2)(i) and (h)(2)(ii)

1910.303(h)(2)(iii), (h)(2)(iv), (h)(2)(v), and (h)(5)(iii)

**1. The final rule organizes these requirements based on whether the installations are indoors or outdoors. (The existing standard organizes them based on whether or not the installations are accessible to unqualified employees).

2. Adds requirements intended to prevent tampering by the general public.

3. Removes requirement to lock underground box covers weighing more than 45.4 kg.

1910.303(h)(3), introductory text

1910.303(h)(3)

No substantive change.

1910.303(h)(3)(i)

1910.303(h)(5)(i) Table S-2, Note 3

**The distances in Table S-2 for the depth of working space in front of electric equipment are increased for new installations to match the distances in NFPA 70E-2000.

1910.303(h)(3)(ii)

1910.303(h)(5)(iv)

No substantive change.

1910.303(h)(3)(iii)

1910.303(h)(5)(v)

**The distances in Table S-3 for the elevations of unguarded live parts are increased for new installations to match the distances in NFPA 70E-2000.

1910.303(h)(4)(i)

**The existing standard requires a second entrance to give access to the working space about switchboards and control panels over 600 V if the equipment exceeds 1.22 m in width if it is practical to install a second entrance. The final rule requires an entrance on each end of switchboards and panelboards exceeding 1.83 m unless the working space permits a continuous and unobstructed way of travel or the working space is doubled. In addition, the final rule requires the lone entrance permitted under either of these exceptions to be at least the distance specified in Table S-2 from exposed live parts.

1910.303(h)(4)(ii)

No substantive change.

1910.303(h)(5)(ii)

**Adds requirements for equipment operating at 600 V or less installed in rooms or enclosures containing exposed live parts or exposed wiring operating at more than 600 V.

1910.303(h)(5)(vi)

**Adds requirements limiting the installation of pipes or ducts that are foreign to electrical installation operating at more than 600 V.

§ 1910.304 Wiring design and protection

1910.304(a)(1)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.304(a)(2)

No substantive change.

1910.304(a)(3)

No substantive change.

1910.304(b)(1)

**Adds requirements for the identification of multiwire branch circuits.

1910.304(b)(2)(i)

**Adds requirements that receptacles installed on 15- and 20-ampere circuits be of the grounding type and that grounding-type receptacles be installed in circuits within their rating.

1910.304(b)(2)(ii)

**Adds a requirement for grounding contacts on receptacles to be effectively grounded.

1910.304(b)(2)(iii)

**Adds requirements on the methods used to ground receptacles and cord connectors.

1910.304(b)(2)(iv)

**Adds requirements on the replacement of receptacles.

1910.304(b)(2)(v)

**Adds a requirement that receptacles installed on branch circuits having different voltages, frequencies, or types of current be noninterchangeable.

1910.304(b)(3)

**Adds requirements for ground fault circuit interrupter protection. (See the discussion of these requirements later in this section of the preamble).

1910.304(b)(2)

1910.304(b)(4), introductory text

No significant change.

1910.304(b)(4)(i)

**Adds requirements for ratings of lampholders.

1910.304(b)(4)(ii)

**Adds requirements for ratings of receptacles.

1910.304(b)(5)

**Adds requirements for receptacles to be installed wherever cords with attachment plugs are used.

1910.304(c), introductory text

No significant change. (The requirements in existing paragraph (c)(5) are placed in a separate paragraph (d)).

1910.304(c)(1)

**Adds a requirement for the separation of conductors on poles.

1910.304(c)(2)

Increases the minimum clearances for new installations of open conductors and service drops to match those in NFPA 70E-2000.

1910.304(c)(3)

1910.304(c)(3)(i)

No substantive change. (The final rule clarifies that paragraph (c)(2) applies to platforms, projections, or surfaces from which runs of open conductors can be reached).

1910.304(c)(3)(ii)

**Adds restrictions for installing overhead service conductors near building openings through which materials may be moved.

1910.304(c)(4)

**Adds an exception to the minimum clearance requirement for conductors attached to the side of a building. (The final rule also clarifies that paragraph (c)(2) applies to roof surfaces that are subject to pedestrian or vehicular traffic).

1910.304(c)(5)

1910.304(d)

No substantive change.

1910.304(d)(1)(i)

1910.304(e)(1)(i)

No substantive change.

1910.304(d)(1)(ii)

1910.304(e)(1)(ii)

No substantive change.

1910.304(e)(1)(iii)

**Adds a requirement for service disconnecting means to be suitable for the prevailing conditions.

1910.304(d)(2)

1910.304(e)(2)

No substantive change.

1910.304(e)(1), introductory text

1910.304(f)(1), introductory text

No substantive change.

1910.304(e)(1)(i)

1910.304(f)(1)(i)

No substantive change.

1910.304(e)(1)(ii)

1910.304(f)(1)(ii)

No substantive change.

1910.304(e)(1)(iii)

1910.304(f)(1)(iii)

**The types of circuits that are allowed to have a single switch disconnect for multiple fuses are now specified in the standard.

1910.304(e)(1)(iv)

1910.304(f)(1)(iv)

No substantive change.

1910.304(e)(1)(v)

1910.304(f)(1)(v)

**Adds a requirement to clarify that handles of circuit breakers and similar moving parts also need to be guarded so that they do not injure employees.

1910.304(e)(1)(vi)(A)

1910.304(f)(1)(vi)

No substantive change.

1910.304(e)(1)(vi)(B)

1910.304(f)(1)(vii)

No substantive change.

1910.304(e)(1)(vi)(C)

1910.304(f)(1)(viii)

**Adds circuit breakers used on 277-volt fluorescent lighting circuits to the types of breakers required to be marked “SWD.”

1910.304(f)(1)(ix)

**Adds a requirement to clarify ratings of circuit breakers.

1910.304(e)(2)

1910.304(f)(2)

**Adds specific requirements on how to protect feeders and branch circuits energized at more than 600 volts.

1910.304(f), introductory text

1910.304(g), introductory text

No substantive change.

1910.304(f)(1), introductory text

1910.304(g)(1), introductory text

No substantive change.

1910.304(f)(1)(i)

1910.304(g)(1)(i)

No substantive change.

1910.304(f)(1)(ii)

1910.304(g)(1)(ii)

No substantive change.

1910.304(f)(1)(iii)

1910.304(g)(1)(iii)

No substantive change.

1910.304(f)(1)(iv)

1910.304(g)(1)(iv)

No substantive change. (The specific voltage ratings in existing paragraphs (g)(1)(iv)(B) and (g)(1)(iv)(C) are being removed. However, this is not a substantive change as those are the voltages used in the described systems).

1910.304(f)(1)(v)

1910.304(g)(1)(v)

**Adds an exception to the requirement to ground systems for high-impedance grounded systems of 480 V to 1000 V under certain conditions.

1910.304(f)(2)

1910.304(g)(2)

**No substantive change. (The standard adds descriptions of which conductor is to be grounded for the different systems).

1910.304(g)(3)

**Changes requirements for grounding portable and vehicle mounted generators so that the requirements are equivalent to those in OSHA's Construction Standards (§ 1926.404(f)(3)). The sentence in the construction standard reading: “No other [nonneutral] conductor need be bonded to the generator frame” has been dropped from the general industry version. This sentence is not regulatory in nature, and its omission has no effect on the requirement.

1910.304(f)(3)

1910.304(g)(4)

**No longer allows employers to use a cold water pipe as a source of ground for installations made or modified after the effective date.

1910.304(f)(4)

1910.304(g)(5)

**Adds a requirement that the path to ground be effective.

1910.304(f)(5)(i)

1910.304(g)(6)(i)

No substantive change.

1910.304(f)(5)(ii)

1910.304(g)(6)(ii)

No substantive change.

1910.304(f)(5)(iii)

1910.304(g)(6)(iii)

No substantive change.

1910.304(f)(5)(iv)

1910.304(g)(6)(iv) and (g)(6)(v)

**The exceptions for grounding fixed equipment operating at more than 150 V are extended to all fixed electric equipment regardless of voltage. Also, the final rule includes a new exception for double-insulated equipment.

1910.304(f)(5)(v)

1910.304(g)(6)(vi) and (g)(6)(vii)

**Adds the following equipment to the list of cord- and plug-connected equipment required to be grounded: stationary and fixed motor-operated tools and light industrial motor-operated tools.

1910.304(f)(5)(vi)

1910.304(g)(7)

**Adds frames and tracks of electrically operated hoists to the list of nonelectrical equipment required to be grounded.

1910.304(f)(6)

1910.304(g)(8)

No substantive change.

1910.304(f)(7)(i)

1910.304(g)(9), introductory text

No substantive change.

1910.304(f)(7)(ii)

1910.304(g)(9)(i)

No substantive change.

1910.304(f)(7)(iii)

1910.304(g)(9)(ii)

No substantive change.

§ 1910.305 Wiring methods, components, and equipment for general use

1910.305(a), introductory text

No substantive change.

1910.305(a)(1)(i)

**Adds a requirement that equipment be bonded so as to provide adequate fault-current-carrying capability. Also, clarifies that nonconductive coatings need to be removed unless the fittings make this unnecessary.

1910.305(a)(1)(ii)

**Adds an exception to the bonding requirement for the reduction of electrical noise.

1910.305(a)(1)(ii)

1910.305(a)(1)(iii)

No substantive change.

1910.305(a)(2), introductory text

No substantive change. Removes the provision allowing temporary wiring to be of a class less than permanent wiring per the 2002 NEC. The change has no substantive effect because: (1) The term “a class less than” is not defined, and (2) temporary wiring is required to meet the same requirements regardless of the deleted language. (Both the final rule and the existing standard contain the following requirement: “Except as specifically modified in this paragraph, all other requirements of this subpart for permanent wiring shall apply to temporary wiring installations.”).

1910.305(a)(2)(i), introductory text

No substantive change.

1910.305(a)(2)(i)(A)

Removes demolition from the list of activities for which temporary wiring is permitted. Demolition is a form of construction work, which is not covered by the Subpart S installation requirements.

1910.305(a)(2)(i)(B)

1910.305(a)(2)(i)(C)

**Adds emergencies to the list of activities for which temporary wiring is permitted.

1910.305(a)(2)(i)(C)

1910.305(a)(2)(i)(B)

No substantive change.

1910.305(a)(2)(ii)

**Clarifies that temporary wiring must be removed when the project or purpose for which it was used has been completed.

1910.305(a)(2)(ii)

1910.305(a)(2)(iii)

**Adds “construction-like activities” to the list of permitted uses for temporary electrical installations over 600 volts.

1910.305(a)(2)(iii)(A)

1910.305(a)(2)(iv)

**Feeders may now only be run as single insulated conductors when accessible to qualified employees only and used for experiments, development work, or emergencies. (Individual requirements are placed in separate paragraphs).

1910.305(a)(2)(iii)(B)

1910.305(a)(2)(v)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.305(a)(2)(iii)(C)

1910.305(a)(2)(vi)

No substantive change.

1910.305(a)(2)(iii)(D)

1910.305(a)(2)(vii)

No substantive change.

1910.305(a)(2)(iii)(E)

1910.305(a)(2)(viii)

**Adds a requirement that disconnecting means for a multiwire circuit simultaneously disconnect all ungrounded conductors of the circuit.

1910.305(a)(2)(iii)(F)

1910.305(a)(2)(ix)

**This provision no longer allows installing fixtures or lampholders more than 2.1 meters above the working surface as a means of guarding. Also, the final rule adds a requirement for grounding metal-case sockets.

1910.305(a)(2)(iii)(G)

1910.305(a)(2)(x)

No substantive change.

1910.305(a)(2)(xi)

**Adds requirements for cable assemblies and flexible cords and cables to be adequately supported.

1910.305(a)(3)(i)(a)

1910.305(a)(3)(i)

No substantive change. (Some raceway and cable types that were included in generic terms have been explicitly added to the list of wiring methods acceptable in cable trays).

1910.305(a)(3)(i)(b)

1910.305(a)(3)(ii)

**Adds several types of cables and single insulated conductors to the list of types permitted in industrial establishments.

1910.305(a)(3)(iii)

**Adds a requirement limiting the use of metallic cable trays as an equipment grounding conductor.

1910.305(a)(3)(i)(c)

1910.305(a)(3)(iv)

No substantive change.

1910.305(a)(3)(ii)

1910.305(a)(3)(v)

No substantive change.

1910.305(a)(4)(i)

No substantive change.

1910.305(a)(4)(ii)

**Adds specific support requirements and limits the application of these requirements to conductors smaller than No. 8.

1910.305(a)(4)(iii)

No substantive change.

1910.305(a)(4)(iv)

No substantive change.

1910.305(a)(4)(v)

No substantive change.

1910.305(b)(1)

1910.305(b)(1)(i) and (b)(1)(ii)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.305(b)(1)(iii)

**Adds requirements for supporting cables entering cabinets, cutout boxes, and meter sockets.

1910.305(b)(2)

1910.305(b)(2)(i)

No substantive change.

1910.305(b)(2)(ii)

**Adds a requirement for any exposed edge of a combustible ceiling finish at a fixture canopy or pan to be covered with noncombustible material.

1910.305(b)(3)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.305(c)(1)

1910.305(c)(1), (c)(2), and (c)(3)(i)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.305(c)(3)(ii)

**Adds a requirement for load terminals on switches to be deenergized when the switches are open except under limited circumstances.

1910.305(c)(4)

**Adds a specific requirement for flush-mounted switches to have faceplates that completely cover the opening and that seat against the finished surface.

1910.305(c)(2)

1910.305(c)(5)

**Adds a requirement to ground faceplates for snap switches.

1910.305(d)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.305(e)(1)

**Adds a requirement for metallic cabinets, cutout boxes, fittings, boxes, and panelboard enclosures installed in damp or wet locations to have an air space between the enclosure and the mounting surface.

1910.305(e)(2)

1910.305)(e)(2)

No substantive change.

1910.305(f)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.305(g)(1)(i)

1910.305(g)(1)(i) and (g)(1)(ii)

**Adds the following to the types of connections permitted for flexible cords and cables: Portable and mobile signs and connection of moving parts. The final rule also clarifies that flexible cords and cables may be used for temporary wiring as permitted in final § 1910.305(a)(2).

1910.305(g)(1)(ii)

1910.305(g)(1)(iii)

No substantive change.

1910.305(g)(1)(iii)

1910.305(g)(1)(iv)

No substantive change. (Clarifies that flexible cords and cables may not be installed inside raceways).

1910.305(g)(1)(iv)

1910.305(g)(1)(v)

**Permits additional cord types to be used in show windows and show cases.

1910.305(g)(2)(i)

**Adds new types of cords to the list of those that must be marked with their type designation.

1910.305(g)(2)(ii)

**Changes the minimum size of hard service and junior hard service cords that may be spliced from No. 12 to 14.

1910.305(g)(2)(iii)

No substantive change.

1910.305(h)

1910.305(h), introductory text, (h)(1), (h)(2), (h)(3), (h)(6), (h)(7), and (h)(8)

**Permits the minimum size of the insulated ground-check conductor of Type G-GC cables to be No. 10 rather than No. 8. (Individual requirements are placed in separate paragraphs).

1910.305(h)(4)

**Adds a requirement for shields to be grounded.

1910.305(h)(5)

**Adds minimum bending radii requirements for portable cables.

1910.305(i)(1)

No substantive change.

1910.305(i)(2)

No substantive change.

1910.305(i)(3)

**Also permits fixture wire to be used in fire alarm circuits.

1910.305(j)(1)(i)

No substantive change.

1910.305(j)(1)(ii)

No substantive change. (Clarifies that metal-shell paper-lined lampholders may not be used for handlamps).

1910.305(j)(1)(iii)

**Adds a requirement that the grounded circuit conductor, where present, be connected to the screw shell.

1910.305(j)(1)(iv)

No substantive change.

1910.305(j)(2)(i)

**Adds requirements to ensure that attachment plugs and connectors have no exposed live parts.

1910.305(j)(2)(i)

1910.305(j)(2)(ii)

No substantive change.

1910.305(j)(2)(iii)

**Clarifies that nongrounding-type receptacles may not be used with grounding-type attachment plugs.

1910.305(j)(2)(ii)

1910.305(j)(2)(iv)

No substantive change.

1910.305(j)(2)(v), (j)(2)(vi), and (j)(2)(vii)

**Adds requirements for receptacles outdoors to be installed in weatherproof enclosures appropriate for the use of the receptacle and for the location.

1910.305(j)(3)(i)

No substantive change.

1910.305(j)(3)(ii)

**Adds a requirement to group and identify disconnecting means for appliances supplied by more than one source.

1910.305(j)(3)(iii)

**Adds requirements for marking frequency and required external overload protection for appliances.

1910.305(j)(3)(iv)

**Clarifies that markings must be visible or easily accessible after installation.

1910.305(j)(4), introductory text

No substantive change.

1910.305(j)(4)(i)

No substantive change.

1910.305(j)(4)(ii)(A)

1910.305(j)(4)(ii)

No substantive change.

1910.305(j)(4)(ii)(B)

1910.305(j)(4)(iii)

No substantive change.

1910.305(j)(4)(ii)(C)

Removed. All disconnecting means must be capable of being locked in the open position by §§ 1910.302(c) and 1910.303(f)(4).

1910.305(j)(4)(ii)(D)

1910.305(j)(4)(iv)

No substantive change.

1910.305(j)(4)(ii)(E)

1910.305(j)(4)(v)

No substantive change.

1910.305(j)(4)(ii)(F)

1910.305(j)(4)(vi)

No substantive change.

1910.305(j)(4)(iii)

1910.305(j)(4)(vii)

No substantive change.

1910.305(j)(4)(iv)(A)

Removed. Covered by § 1910.303(g)(2), (h)(2), and (h)(4)(iii).

1910.305(j)(4)(iv)(B)

1910.305(j)(4)(viii)

No substantive change.

1910.305(j)(5)(i)

No substantive change.

1910.305(j)(5)(ii)

No substantive change.

1910.305(j)(5)(iii)

No substantive change.

1910.305(j)(5)(iv)

No substantive change. (Oil-insulated transformers installed indoors are presumed to present a hazard to employees since a transformer failure will lead to a fire within the building unless the transformer is installed in a vault).

1910.305(j)(5)(v)

No substantive change.

1910.305(j)(5)(vi)

No substantive change.

1910.305(j)(5)(vii)

No substantive change.

1910.305(j)(5)(viii)

No substantive change.

1910.305(j)(6)(i)

No substantive change.

1910.305(j)(6)(ii), introductory text

No substantive change.

1910.305(j)(6)(ii)(A) and (j)(6)(ii)(B)

**Adds requirements to provide disconnecting means of adequate capacity for capacitors operating at more than 600 V.

1910.305(j)(6)(ii)(A)

1910.305(j)(6)(ii)(C)

No substantive change.

1910.305(j)(6)(ii)(B)

1910.305(j)(6)(ii)(D)

No substantive change.

1910.305(j)(7)

No substantive change.

§ 1910.306 Specific purpose equipment and installations

1910.306(a)(1)

1910.306(a)(1)(i), (a)(2)(i), and (a)(2)(ii)

**Reorganized and clarified the requirements for disconnecting means for signs. The final rule does not apply these requirements to exit signs.

1910.306(a)(1)(ii)

**Adds a requirement for the disconnects for signs located within fountains to be at least 1.52 m from the fountain wall.

1910.306(a)(2)

1910.306(a)(2)(iii)

No substantive change.

1910.306(b), introductory text

No substantive change.

1910.306(b)(1)(i)

1910.306(b)(1)

**Adds specific requirements for the type and location of disconnecting means for runway conductors.

1910.306(b)(1)(ii)

1910.306(b)(2)

No substantive change. (The final rule reorganizes these requirements).

1910.306(b)(2)

1910.306(b)(3)

No substantive change.

1910.306(b)(3)

1910.306(b)(4)

No substantive change.

1910.306(c)

1910.306(c), introductory text

**This paragraph now covers wheelchair lifts, and stairway chair lifts.

1910.306(c)(1)

No substantive change.

1910.306(c)(2)

1910.306(c)(8)

No substantive change.

1910.306(c)(3)

1910.306(c)(2)

No substantive change.

1910.306(c)(3)

**Adds requirements for the type of disconnecting means.

1910.306(c)(4)

**Adds requirements for the operation of disconnecting means.

1910.306(c)(5)

**Adds requirements for the location of disconnecting means.

1910.306(c)(6)

**Adds requirements for the identification of disconnecting means.

1910.306(c)(7)

**Adds requirements for disconnecting means for single car and multicar installations supplied by more than one source.

1910.306(c)(9)

**Adds requirements for warning signs for interconnected multicar controllers.

1910.306(c)(10)

**Adds exceptions related to the location of motor controllers.

1910.306(d)(1)

**Adds requirements for the type and rating of the disconnecting means.

1910.306(d)(2)

Clarifies that a supply circuit switch may be used as a disconnecting means if the circuit supplies only one welder.

1910.306(e)

**Adds a requirement to group the disconnecting means for the HVAC systems serving information technology rooms with the disconnecting means for the information technology equipment. The final rule exempts integrated electrical systems covered by § 1910.308(g). (The existing standard refers to this equipment as data processing equipment).

1910.306(f), introductory text

**Adds coverage of X-rays for dental or medical use.

1910.306(f)(1)(i)

No substantive change.

1910.306(f)(1)(ii)

No substantive change.

1910.306(f)(2)(i)

No substantive change.

1910.306(f)(2)(ii)

No substantive change.

1910.306(g)(1)

1910.306(g), introductory text

No substantive change.

1910.306(g)(2)(i)

1910.306(g)(1)(i)

No substantive change.

1910.306(g)(2)(ii)

1910.306(g)(1)(ii)

No substantive change.

1910.306(g)(2)(iii)

1910.306(g)(1)(iii)

**Adds a requirement for the installation of doors or detachable panels to provide access to internal parts. Adds a requirement that detachable panels not be readily removable.

1910.306(g)(2)(iv)

1910.306(g)(1)(iv)

No substantive change.

1910.306(g)(2)(v)

1910.306(g)(1)(v)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.306(g)(2)(vi)

1910.306(g)(1)(vi)

**Adds a requirement to ensure adequate rating of disconnecting means. The final rule also clarifies when the supply circuit disconnecting means may be used as the disconnecting means for induction and dielectric heating equipment.

1910.306(g)(3)

1910.306(g)(2)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.306(h)(1)

1910.306(h), introductory text

No substantive change.

1910.306(h)(2)

1910.399

No substantive change.

1910.306(h)(3)

1910.306(h)(1)

No substantive change.

1910.306(h)(4)(i) and (h)(4)(ii)

1910.306(h)(2)

No substantive change. (The two provisions are combined into one paragraph).

1910.306(h)(5)(i)

1910.306(h)(3)(i)

No substantive change.

1910.306(h)(5)(ii)

1910.306(h)(3)(ii)

No substantive change.

1910.306(h)(6)(i)

1910.306(h)(4)(i)

**Adds requirements limiting primary and secondary voltage on isolating transformers supplying receptacles for ungrounded cord- and plug-connected equipment. Also, adds requirement for overcurrent protection for circuits supplied by these transformers.

1910.306(h)(6)(ii)

1910.306(h)(4)(ii)

No substantive change.

1910.306(h)(6)(iii)

1910.306(h)(4)(iii)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.306(h)(7)(i) and (h)(7)(ii)

1910.306(h)(5)(i)

No substantive change.

1910.306(h)(7)(iii)

1910.306(h)(5)(ii)

No substantive change.

1910.306(h)(7)(iv)

1910.306(h)(5)(iii)

No substantive change.

1910.306(h)(8)

1910.306(h)(6)

No substantive change.

1910.306(h)(9)

1910.306(h)(7)

No substantive change.

1910.306(i)(1)

No substantive change.

1910.306(i)(2)

**Allows the disconnecting means for a center pivot irrigation machine to be located not more than 15.2 m (50 ft) from the machine if the disconnecting means is visible from the machine. (Individual requirements are placed in separate paragraphs).

1910.306(j)(1)

1910.306(j), introductory text

**Clarifies that hydro-massage bathtubs are covered by this paragraph.

1910.306(j)(2)(i)

1910.306(j)(1)(i)

No substantive change.

1910.306(j)(1)(ii)

**Extends the boundary within which receptacles require ground-fault circuit interrupter protection from 4.57 m (15 ft) to 6.08 m (20 ft) for new installations.

1910.306(j)(1)(iii)

**Adds requirements for the installation of at least one receptacle near permanently installed pools at dwelling units.

1910.306(j)(2)(ii)(A)

1910.306(j)(2)(i)

**Clarifies that ceiling suspended (paddle) fans are covered by this requirement.

1910.306(j)(2)(ii)(B)

1910.306(j)(2)(ii)

No substantive change.

1910.306(j)(3)

No substantive change.

1910.306(j)(4)(i)

No substantive change.

1910.306(j)(4)(ii)

No substantive change.

1910.306(j)(4)(iii)

**Adds a requirement to guard lighting fixtures facing upward.

1910.306(j)(5)

No substantive change.

1910.306(k)

**Adds requirements for carnivals, circuses, fairs, and similar events.

§ 1910.307 Hazardous (classified) locations.

1910.307(a)

**Adds the Zone classification system for Class I locations. (See detailed discussion later in this section of the preamble).

1910.307(b)

**Adds documentation requirements for hazardous locations classified using either the division or zone classification system. (See detailed discussion later in this section of the preamble).

1910.307(b), introductory text

1910.307(c), introductory text

No substantive change.

1910.307(b)(1)

1910.307(c)(1)

No substantive change.

1910.307(b)(2)(i)

1910.307(c)(2)(i)

No substantive change.

1910.307(b)(2)(ii), introductory text

1910.307(c)(2)(ii), introductory text

No substantive change.

1910.307(b)(2)(ii)(A)

1910.307(c)(2)(ii)(A)

No substantive change.

1910.307(b)(2)(ii)(B)

1910.307(c)(2)(ii)(B)

**Also permits fixtures approved for Class II, Division 2 locations to omit the group marking.

1910.307(b)(2)(ii)(C)

1910.307(c)(2)(ii)(C)

No substantive change.

1910.307(b)(2)(ii)(D)

1910.307(c)(2)(ii)(D)

No substantive change.

1910.307(c)(2)(ii)(E)

**Adds a requirement that electric equipment suitable for an ambient temperature exceeding 40 °C (104 °F) be marked with the maximum ambient temperature.

1910.307(b)(3)

1910.307(c)(3)

No substantive change.

1910.307(b)(3), Note

1910.307(c)(3), Note

The last sentence of the note is removed to make it clear that the OSHA standard does not incorporate the National Electrical Code by reference. The NEC continues to be a guideline that employers may reference in determining the type and design of equipment and installations that will meet the OSHA standard.

1910.307(c)

1910.307(d)

No substantive change.

1910.307(d)

1910.307(e)

No substantive change.

1910.307(f)

**The final rule adds a list of specific protective techniques for electrical installations in hazardous locations classified under the division classification system.

1910.307(g)

**Adds the zone classification system as an alternative method of installing electric equipment in hazardous locations. This paragraph sets the protective techniques and other requirements necessary for safe installation of electric equipment in hazardous locations classified under the zone classification system. (See detailed discussion later in this section of the preamble).

§ 1910.308 Special systems

1910.308(a), introductory text

No substantive change.

1910.308(a)(1)(i)

1910.308(a)(1)(i) and (a)(3)(ii)

**Adds the following wiring methods to those acceptable for installations operating at more than 600 V: Electrical metallic tubing, rigid nonmetallic conduit, busways, and cable bus. The proposal also removes the specific requirement to support cables having a bare lead sheath or a braided outer covering in a manner to prevent damage to the braid or sheath. This hazard is covered by § 1910.303(b)(1) and (b)(8)(i) and new § 1910.308(a)(4).

1910.308(a)(1)(ii)

No substantive change.

1910.308(a)(2) and (a)(3)(i)

** Adds requirements to ensure that high-voltage cables can adequately handle the voltage stresses placed upon them and to ensure that any coverings are flame retardant.

1910.308(a)(4)

**Adds requirements for the protection of high-voltage cables against moisture and physical damage where the cable conductors emerge from a metal sheath.

1910.308(a)(2)(i)

1910.308(a)(5)(i)

No substantive change.

1910.308(a)(5)(ii)

**Adds requirements for fuses to protect each ungrounded conductor, for adequate ratings of fuses installed in parallel, and for the protection of employees from power fuses of the vented type.

1910.308(a)(2)(ii)

1910.308(a)(5)(iii)

**Clarifies that distribution cutouts are not suitable for installation in buildings or transformer vaults.

1910.308(a)(5)(iv)

**Adds requirements for fused cutouts to either be capable of interrupting load current or be supplemented by a means of interrupting load current. In addition, a warning sign would be required for fused cutouts that cannot interrupt load current.

1910.308(a)(5)(v)

**Adds a requirement for guarding nonshielded cables and energized parts of oil-filled cutouts.

1910.308(a)(5)(vi)

**Adds requirements to ensure that load interrupting switches will be protected against interrupting fault current and to provide for warning signs for backfed switches.

1910.308(a)(2)(iii)

1910.308(a)(5)(vii)

No substantive change.

1910.308(a)(3)

1910.308(a)(6)

No substantive change.

1910.308(a)(4)(i)

1910.308(a)(7), introductory text

No substantive change.

1910.308(a)(4)(ii)

1910.308(a)(7)(i) and (a)(7)(iii)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.308(a)(7)(ii)

**Clarifies that multiconductor portable cable may supply mobile equipment.

1910.308(a)(4)(iii)

1910.308(a)(7)(iv) and (a)(7)(v)

No substantive change. (Individual requirements are placed in separate paragraphs).

1910.308(a)(7)(vi)

**Limits the conditions under which switch or contactor enclosures may be used as junction boxes or raceways.

1910.308(a)(4)(iv)

1910.308(a)(7)(vii)

No substantive change.

1910.308(a)(4)(v)

1910.308(a)(7)(viii)

No substantive change.

1910.308(b)(1)

1910.308(b), introductory text

No substantive change.

1910.308(b)(2)

1910.308(b)(1)

No substantive change.

1910.308(b)(3)

1910.308(b)(2)

**Clarifies that emergency illumination includes all required means of egress lighting, illuminated exit signs, and all other lights necessary to provide required illumination.

1910.308(b)(3)

**Adds requirements to provide signs indicating the presence and location of on-site emergency power sources under certain conditions.

1910.308(c)(1), introductory text

No substantive change.

1910.308(c)(1)(i), (c)(1)(ii), and (c)(1)(iii)

**Clarifies the power limitations of Class 1, 2, and 3 remote control, signaling, and power-limited circuits based on equipment listing.

1910.308(c)(2)

No substantive change.

1910.308(c)(3)

**Adds requirements for the separation of cables and conductors of Class 2 and Class 3 circuits from cables and conductors of other types of circuits.

1910.308(d)(1)

No substantive change.

1910.308(d)(2), introductory text

No substantive change.

1910.308(d)(2)(i)

No substantive change.

1910.308(d)(2)(ii)

**Adds a requirement for power-limited fire alarm circuit power sources to be listed and marked as such.

1910.308(d)(3)

1910.308(d)(3)(i)

No substantive change.

1910.308(d)(4)

1910.308(d)(3)(ii), (d)(3)(iii), and (d)(3)(iv)

**Clarifies the requirements for installing power-limited fire-protective signaling circuits with other types of circuits. (Individual requirements are placed in separate paragraphs).

1910.308(d)(5)

1910.308(d)(4)

No substantive change.

1910.308(e)(1)

1910.308(e), introductory text

No substantive change.

1910.308(e)(2)

1910.308(e)(1)

**Clarifies the requirement for listed primary protectors to make it clear that circuits confined within a block do not need protectors.

1910.308(e)(3)(i)

1910.308(e)(2)(i) and (e)(2)(ii)

No substantive change.

1910.308(e)(3)(ii)

1910.308(e)(2)(iii)

No substantive change.

1910.308(e)(3)(iii)

1910.308(e)(2)(iv)

No substantive change.

1910.308(e)(4)

1910.308(e)(3)

No substantive change.

1910.308(e)(5)

1910.308(e)(4)

No substantive change.

1910.308(f)

**Adds requirements to separate conductors of solar photovoltaic systems from conductors of other systems and to provide a disconnecting means for solar photovoltaic systems.

1910.308(g)

**Adds an exception to the provisions on the location of overcurrent protective devices for integrated electrical systems.

Note to table:

**These new and revised provisions are included in the 2000 and 2004 editions of NFPA 70E standard. The NFPA 70E Committee believes that these provisions, which were taken from the 1999 and 2002 NEC, respectively, are essential to employee safety. OSHA agrees with the consensus of NFPA's expert opinion that these requirements are reasonably necessary to protect employees and has included them in the final rule. On occasion, OSHA has rewritten the provision to lend greater clarity to its requirements. However, these editorial changes to the language of NFPA 70E do not represent substantive differences. NFPA's handling of these provisions and the rationale underpinning them is a matter of public record for the NEC and NFPA 70E and is part of the record for this rulemaking (Exs. 2-9 through 2-18). OSHA agrees with the rationale in this record as it pertains to the new and revised provisions the Agency is adopting.

F. General Requirements (§ 1910.303)

Paragraph (b) of proposed § 1910.303 contained a general requirement for electric equipment to be free of recognized hazards likely to cause death or serious physical harm to employees. This provision also contained criteria for judging the safety of electric equipment. One of the criteria was suitability for installation and use in accordance with Subpart S, and a note following paragraph (b)(1)(i) indicated that listing or labeling by a nationally recognized testing laboratory could be evidence of suitability.

The National Multihousing Council recommended adding a second note to this paragraph to indicate that nothing in this provision was to be taken as a directive that limits a local jurisdiction's authority to amend the adopted electrical code (Ex. 4-20).

Local electrical inspection authorities have jurisdiction over public safety as well as employee safety and this jurisdiction is not preempted by OSHA standards. OSHA does not believe that a note to the standard is necessary to clarify this authority. Indeed, the recommended note might serve to confuse employers and employees, leading them to believe that OSHA might enforce those local requirements. Therefore, § 1910.303(b)(1)(i) in the final standard does not include such a note.

In paragraph (g) of proposed § 1910.303, OSHA would have required the employer to maintain sufficient access and working space about electric equipment to permit ready and safe operation and maintenance of equipment. This paragraph would have required the access and working space to meet certain minimum dimensions. One commenter expressed concern regarding the physical space about electric equipment on ships (Ex. 3-7). This commenter argued that, in shipbuilding and repair, the limited space on a ship is a design concern for shore-based equipment. He stated that some shore-based electric equipment is placed in locations that ensure safe access to disconnect switches in the event of an emergency or routine connection of other equipment and that the working space in these locations can be limited. However, he stated that his company deenergizes and removes shore-based equipment before servicing or maintenance.

OSHA believes that this commenter's installation complies with final § 1910.303(g). The introductory text to paragraph (g)(1) contains the general requirement that sufficient access and working space shall be provided and maintained about all electric equipment to permit ready and safe operation and maintenance of such equipment. These provisions ensure that employees maintaining electric equipment while it is energized have enough room to work without danger of contacting energized parts and grounded parts or two circuit parts energized at different potentials simultaneously. The specific dimensions required by paragraph (g)(1)(i) apply only to equipment likely to require examination, adjustment, servicing, or maintenance while it is energized. As long as the employer implements, communicates, and enforces a policy to ensure that the equipment is deenergized before employees engage in any of these tasks that might expose them to contact with energized parts, paragraph (g)(1)(i) does not apply, and the equipment need not provide the specific amount of working space required by that provision. In the commenter's case, the employer not only deenergizes the equipment but removes it from the space in question altogether, thus providing an additional measure of safety. On the other hand, if the equipment were not deenergized, then employees would not be able to work on the equipment safely.

Table S-3 and § 1910.303(h)(5)(v) in the proposed rule would have required a minimum elevation of 2.8 m (9.0 ft) for unguarded live parts operating at 601 to 7500 V and located above working space. A note following proposed Table S-3 permitted the minimum elevation to be 2.6 m (8.5 ft) for installations built before the effective date of the final standard. However, Table S-3 in the existing standard provides for a minimum elevation of 2.4 m (8.0 ft) for

installations built before April 16, 1981, if the voltage is in the range of 601 to 6600 V. OSHA unintentionally omitted this exception for older installations from the footnote to Table S-3 in the proposal. The Agency does not intend for installations made before April 16, 1981, to be modified to provide an additional 0.2 m (0.5 ft) of elevation. Therefore, the Agency is carrying forward the language from the existing standard allowing for the reduced minimum elevation for those older installations.

G. Branch Circuits—Identification of Multiwire Branch Circuits

Identification requirements.

Paragraph (b)(1) of final § 1910.304 adds requirements for identification of multiwire branch circuits. The rule requires that all ungrounded conductors of multiwire branch circuits in a building be identified, where accessible, by phase and system where more than one nominal voltage system exists. It goes on to add that the identification means shall be permanently posted at each branch circuit panelboard. For example, the identification means can be color coding, marking tape, or tagging.

For instance, a building served by both 208Y/120-volt and 480Y/277-volt multiwire branch circuits must use a wiring identification means. One method of meeting final § 1910.304(b)(1) would be to use a color-coded scheme with brown, orange, and yellow insulation for the 480-volt system's phase conductors and black, red, and blue insulation for the 208-volt system's phase conductors. A legend, which may include other information such as the panelboard identification, must be permanently affixed at each branch circuit panelboard to identify the respective phase and system color-coding scheme.

One commenter requested clarification of the term “where accessible” used in § 1910.304(b)(1) of the proposed rule (Ex. 4-14). He questioned whether the identification means must be posted at each pull and junction box. He suggested allowing a color-coding scheme identified in the employer's written electrical safety program.

OSHA believes that the typical means of complying with this provision, which was ultimately taken from 1999 NEC Section 210-4(d),

will be to use conductors with insulation of different colors for each system and post a legend identifying which colors are used with which systems at each panelboard. The color-coded conductors for each circuit are visible at each pull and junction box, which are locations where the conductors are accessible; thus, the employees can determine the voltage on a circuit and at utilization equipment or devices such as motors or receptacle outlets by referring to the legend at the panelboard supplying the circuit. Final § 1910.304(b)(1) requires the legend to be posted at the panelboard for each branch circuit, not at the pull and junction boxes.

Section 210-4(d) of the 1999 NEC reads as follows:

(d)

Identification of Ungrounded Conductors.

Where more than one nominal voltage system exists in a building, each ungrounded conductor of a multiwire branch circuit, where accessible, shall be identified by phase and system. This means of identification shall be permitted to be by separate color coding, marking tape, tagging, or other approved means and shall be permanently posted at each branch-circuit panelboard.

The requirements proposed in § 1910.304(b)(1) and (b)(3) for ungrounded conductors of systems of different voltages to be identified were very similar. Proposed paragraph (b)(1) would have required identification of multiwire branch circuits

only, whereas paragraph (b)(3) would have required identification regardless of whether a circuit was a multiwire circuit. Paragraph (b)(1) was taken from NFPA 70E-2000 Section 2-2.1, and paragraph (b)(3) was taken from NFPA 70E-2000 Section 2-2.3 (Ex. 2-2). In addition, both NFPA sections are taken from 1999 NEC Section 210-4(d). Proposed paragraph (b)(3) inadvertently omitted language from the NFPA standard (Section 2-2.3) restricting its application to multiwire circuits. Although no one submitted comments on this problem, OSHA has decided to correct this error by not carrying proposed § 1910.304(b)(3) into the final rule.

A multiwire branch circuit is a branch circuit that consists of two or more ungrounded conductors that have a voltage between them and a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit and that is connected to the neutral or grounded conductor of the system.

H. Branch Circuits—Ground-Fault Circuit-Interrupters for Employees

Introduction.

Each year many employees suffer electric shocks while using portable electric tools and equipment. The nature of the injuries ranges from minor burns to electrocution. Electric shocks produced by alternating currents (ac) at power line frequency passing through the body of an average adult from hand to foot for 1 second can cause various effects, starting from a condition of being barely perceptible at 1 milliampere to loss of voluntary muscular control for currents from 9 to 25 milliamperes. The passage of still higher currents, from 75 milliamperes to 4 amperes, can produce ventricular fibrillation of the heart; and, finally, immediate cardiac arrest at over 4 amperes. These injuries occur when employees contact electrically energized parts. Typically, the frame of a tool becomes accidentally energized because of an electrical fault (known as a ground fault) that provides a conductive path to the tool casing. For instance, with a grounded electric supply system, when the employee contacts the tool casing, the fault current takes a path through the employee to an electrically grounded object. The amount of current that flows through an employee depends, primarily, upon the resistance of the fault path within the tool, the resistance of the path through the employee's body, and the resistance of the paths, both line side and ground side, from the employee back to the electric power supply. Moisture in the atmosphere can contribute to the electrical fault by enhancing both the conductive path within the tool and the external ground path back to the electric power supply. Dry skin can have a resistance range of anywhere from about 500 to 500,000 ohms and wet skin can have a resistance range of about 200 to 20,000, depending on several factors, such as the physical characteristics and mass of the employee. More current will flow if the employee is perspiring or becomes wet because of environmental conditions. If the current is high enough, the employee will suffer a ground-fault electrocution.

One method of protection against injuries from electric shock is the ground-fault circuit-interrupter (GFCI). This device continually monitors the current flow to and from electric equipment. If the current going out to the protected equipment differs by approximately 0.005 amperes (5-milliamperes) from the current returning, then the GFCI will deenergize the equipment within as little as 25 milliseconds, quickly enough to prevent electrocution.

GFCI requirements.

Paragraph (b)(3) of final § 1910.304 sets new requirements for ground-fault circuit-interrupter protection of receptacles and cord connectors used in general industry. Paragraph (b)(3)(i) requires ground-fault circuit protection for all 125-volt, single-phase, 15- and 20-ampere receptacles installed in bathrooms and on rooftops. As noted earlier, this provision only applies to installations made after the effective date of the final rule. Cord sets and cord- and plug-connected equipment in these locations can get wet and expose employees to severe

ground-fault hazards. The NFPA 70E Technical Committee believes, and OSHA agrees, that using 125-volt, 15- and 20-ampere cord- and plug-connected equipment in these locations exposes employees to great enough risk of ground-fault electrocution (as noted earlier) to warrant the protection afforded by GFCIs.

Part I 2-2.4.1 of NFPA 70E, 2000 edition, requires GFCI protection for all 120-volt, single-phase, 15- and 20-ampere receptacles installed in bathrooms and on rooftops for other than dwelling units.

Paragraph (b)(3)(ii) of final § 1910.304 requires GFCI protection for all receptacle outlets on temporary wiring installations that are used during maintenance, remodeling, or repair of buildings, structures, or equipment, or during similar construction-like activities.

Such activities include cleanup, disaster remediation, and restoration of large electrical installations.

See also the discussion of the term “construction-like activities” under the summary and explanation of final § 1910.305(a)(2), later in this section of the preamble. It should be noted that the discussion of the term “construction-like activities” is intended for application only to the use of this term in Subpart S.

OSHA currently requires GFCI protection for 120-volt, single-phase, 15- and 20-ampere temporary receptacle outlets used on construction sites (§ 1926.404(b)(1)). In the 28 years that this requirement has been in effect, the Agency estimates that between about 650 and 1,100 lives have been saved because of it.

Temporary wiring associated with construction-like activities in general industry exposes employees to the same ground-fault hazards as those associated with temporary receptacle outlets on construction sites. In § 1910.304(b)(3)(ii), OSHA is extending the ground-fault protection requirement to temporary receptacles used in construction-like activities performed in general industry. At the same time, this final rule extends protection to temporary wiring receptacles of higher voltage and current ratings (such as 125-volt, single-phase, 30-ampere and 480-volt, three-phase receptacles). It better protects employees from ground-fault hazards than the construction rule because it covers other equipment that is just as subject to damage as 120-volt, single-phase, 15- and 20-ampere equipment and that is more prevalent today than when the construction rule was promulgated over 28 years ago.

In the preamble to the final rule adopting a requirement for GFCIs on construction sites, OSHA estimated that there were between 30 and 45 deaths per year caused by 120-volt ground faults on construction sites, and the Agency determined that nearly all of those deaths could be prevented by the use of GFCI protection or an assured grounding program (41 FR 55701, December 21, 1976). OSHA fatality investigation data indicate that 46 deaths involving 120-volt ground-faults in temporary wiring occurred over the years 1990 to 1996 (the latest year for which data are complete). This is a death rate of only 6.6 per year. Thus, OSHA believes that the rule has saved between 23 and 39 lives per year or, over the 28 years the rule has been in effect, a total of between about 650 and 1,100 lives.

The Agency had proposed not to permit the NFPA 70E “Assured Grounding Program” as an alternative to GFCIs in this rule. NFPA 70E's Assured Grounding Program, differs in several important respects from the assured equipment grounding conductor program in OSHA's construction standards (§ 1926.404(b)(1)). For example, NFPA 70E permits the Assured Grounding Program as an alternative to GFCI protection for personnel (1) for 125-volt, single-phase, 15- and 20-ampere receptacle outlets in industrial establishments only, with conditions of maintenance and supervision that ensure that only qualified personnel are involved, and (2) for receptacle outlets rated other than 125 volts, single-phase, 15, 20, or 30 amperes. The OSHA construction rule recognizes an assured equipment grounding conductor program as an alternative to GFCIs without restriction. Additionally, under its Assured Grounding Program, NFPA 70E requires electric equipment to be tested only when there is evidence of damage. This is in contrast to the assured equipment grounding conductor program required by OSHA's construction standard, which requires electric equipment to be tested after any incident that can reasonably be suspected to have caused damage.

During the development of the proposal, OSHA had considered including NFPA 70E's Assured Grounding Program or the construction standard's assured equipment grounding conductor program requirements as alternatives to GFCIs, but rejected them. In the preamble to the proposal, OSHA gave the following reasons for rejecting NFPA's Assured Grounding Program: (1) The differences between the general industry and construction requirements would have been too confusing for employers who are subject to both standards, and (2) the NFPA alternative would offer less protection for employees than the assured equipment grounding conductor program in OSHA's construction standard. Additionally, OSHA reasoned in the proposal that requiring GFCIs alone, without even the construction standard's assured equipment grounding conductor program as an alternative, would provide better protection for employees. The construction standard's assured equipment grounding conductor program demands constant vigilance on the part of employees to provide them with the same level of protection as GFCIs. Under that program, employers must perform rigorous inspections and tests of cord sets and cord- and plug-connected equipment generally at 3-month intervals and employees must inspect them daily. In contrast, GFCIs constantly monitor the circuit for ground faults and open the circuit when ground-fault current becomes excessive without the need for either the employer or the employee to take action. Because three fourths of all electrical accidents are caused by poor work practices (55 FR 31986), OSHA believes that GFCIs are a more reliable method of protecting employees.

OSHA received several comments generally supportive of the proposed requirement for GFCIs for 125-volt, single-phase, 15- and 20-ampere receptacles installed in bathrooms or on rooftops and for all 125-volt, single-phase, 15-, 20-, and 30-ampere receptacle outlets that are not part of the permanent wiring of the building or structure and that are in use by personnel (Exs. 3-5, 3-6, 3-10, 4-9, 4-23, 4-24). For example, the American Society of Safety Engineers (ASSE) supported the new requirements for GFCI protection of receptacles and cord connectors and for temporary wiring installations, stating that this is an important aspect of the rule (Ex. 3-5). ASSE stated that this requirement will greatly contribute to the rule's effectiveness in saving lives and it is also consistent with OSHA's current requirements in 29 CFR Part 1926 for construction sites. Another commenter supported OSHA's statement in the proposal that GFCIs for temporary wiring installations have been required in the NEC for many years and that the requirement overall does not impose any hardships on employers (Ex. 5-2). One of the commenters agreed that GFCIs provide continuous protection for employees (Ex. 4-9). A comment (Ex. 4-24) from the National Electrical Manufacturers Association (NEMA) stated that GFCIs provide better protection for employees and a safer workplace than the alternate assured equipment grounding conductor program included in OSHA's construction standard. NEMA added that GFCIs provide continuous protection whereas the assured equipment grounding conductor program requires monthly inspection. NEMA recommended that the assured

equipment grounding program not be added as an alternative to GFCIs in the general industry electrical installation standard.

Other commenters opposed OSHA's proposal not to include the assured grounding program as an alternative to GFCIs (Exs. 3-3, 3-6, 3-10, 4-11, 4-14, 4-19, 4-23). Some of them hinted that GFCI-type receptacles and circuit breakers at voltages above 125 volts, 15, 20, and 30 amperes may require constant attention because of nuisance tripping (Exs. 3-6, 3-10, 4-11, 4-19, 4-23). They added that it is possible and likely that construction-type portable equipment used in industry will trip GFCIs during normal operation. For example, Mike Johnson of International Paper argued that portable welding units for the repair of major pieces of equipment such as industrial boilers and other massive pieces of equipment pose a real concern (Ex. 3-6). He noted that the cord sets on such portable equipment are typically heavier and less prone to damage than cords furnished with 125-volt equipment. He further noted his experience with tripping of GFCIs during the normal use of hermetic compressors, which are used for temporary cooling of personnel. Some of those objecting to the omission of the assured equipment grounding conductor program alternative argued that to avoid nuisance tripping on circuits of more than 125 volts, they would be forced to keep circuits very short beyond the location of the GFCI protection (Exs. 4-11, 4-19). Another commenter, Alcoa, supported the use of GFCI protection for all temporary 125-volt, single-phase wiring, including the use of extension cord sets, but did not support the use of GFCI protection on 480-volt, three-phase extension cord sets or 480-volt temporary wiring (Ex. 4-14). Finally, some commenters argued that the lack of commercially available GFCIs at voltages higher than 125 volts makes it impossible to comply with § 1910.304(b)(4)(ii) as proposed (Exs. 4-11, 4-19, 4-23).

These commenters gave three reasons why the Agency should permit an assured equipment grounding conductor program as an alternative to GFCIs, particularly at voltages higher than 125 volts: (1) Because, they asserted, the assured equipment grounding conductor program is equally effective; (2) because of tripping caused by (a) the inherently high leakage current for some electric equipment or (b) the capacitive leakage on long circuits of voltages over 125 volts; and (3) because GFCIs are not available for all branch-circuit voltage and current ratings.

Nothing in the record has convinced the Agency that its preliminary conclusion that GFCIs are more effective protection than the assured equipment grounding conductor program is incorrect. In fact, the 2002 NEC, which permits its assured equipment grounding conductor program as an alternative to GFCIs only in very limited circumstances,

indicates that NFPA has reached the same conclusion. OSHA disagrees with the commenters’ assertion that the assured equipment grounding conductor program provides protection equivalent to GFCIs. Thus, the Agency has determined based on the record that GFCIs are a more effective means of protecting employees than the assured equipment grounding conductor program.

NEC Section 527.6 requires electric shock or electrocution protection for personnel using temporary wiring during activities such as construction, remodeling, maintenance, repair, demolition, and the like. GFCI protection or a written assured equipment grounding conductor program must be used to provide this protection. All 125-volt, single-phase 15-, 20-, and 30-ampere receptacle outlets must have GFCI protection except that in industrial establishments only, where only qualified personnel perform maintenance, the assured equipment grounding conductor program is permitted for specific situations. The limitations of the exception in industrial establishments only are for situations in which: (1) Qualified personnel are using equipment that is not compatible, by design, with GFCI protection or (2) a greater hazard exists if power was interrupted by GFCI protection.

For receptacle outlets other than those rated 125 volts, single phase 15, 20, and 30 amperes, personnel protection must be provided by either GFCI protection or a written assured equipment grounding conductor program.

The Agency cannot determine whether the commenters concerns about tripping caused by capacitive charging currents between the circuit conductors and the equipment grounding conductor at voltages over 125 volts are valid. For multiphase circuits, capacitive currents should balance out across the phases. Even on single-phase circuits, employers should be able to control leakage and capacitive currents by limiting the length of the conductors between the GFCI and the utilization equipment.

However, OSHA recognizes the limited availability of GFCIs for circuits operating at voltages above 125 volts to ground. Consequently, it would be very difficult, if not impossible, for employers to comply with a requirement for GFCI protection for all branch-circuit ratings. For this reason, OSHA has decided to permit an assured equipment grounding conductor program as an alternative to GFCIs when approved GFCIs are unavailable for the voltage and current rating of the circuit involved. However, the final rule does require employers to provide GFCI protection whenever these devices are available at the branch-circuit rating involved. The Agency anticipates that approved 1-, 2-, and 3-pole GFCIs for branch-circuits with ratings above 125 volts and 30 amperes will become available in the future. Employers will need to use those new devices for any temporary wiring installed after they do become available. OSHA will continue to monitor developments in this area and inform employers as appropriate of the availability of GFCIs.

Certain equipment designs cause tripping of GFCIs. For example, some motors, due to design or application, have higher leakage current to ground than a GFCI will allow. In other cases, GFCI tripping can result in undesired consequences. For example, the NEC requires GFCI-protected receptacles in garages at residences but allows for a non-GFCI receptacle for large appliances such as a food freezer. If the GFCI trips, the food in the freezer will spoil. An NEC exception to GFCI protection for temporary installations recognizes the incompatibility of these types of equipment on a GFCI-protected circuit and allows the assured equipment grounding conductor program in place of GFCIs under certain circumstances. Another NEC exception allows the assured equipment grounding conductor program for temporary installations where a greater hazard exists if power is interrupted by a GFCI. For example, a motor for a ventilation fan used to exhaust toxins in the atmosphere may not be compatible with GFCI protection. Loss of the fan because of tripping by a GFCI can pose a risk to employee health and safety. However, OSHA believes that even this type of equipment should not be subject to the risks associated with temporary cord- and plug-connected wiring. The Agency believes that hard-wired methods, which avoid the use of a plug-receptacle combination, afford better protection of employees relying on such critical equipment. Because the GFCI requirement applies only to receptacle outlets, employers can avoid having to install GFCIs by wiring the equipment directly to the circuit conductors at an outlet or panelboard.

Many of the commenters supporting the assured grounding alternative recommended that the Agency include an assured equipment grounding conductor program consistent with OSHA's existing requirements in 29 CFR 1926.404(b)(1)(iii) as an alternative to using GFCIs for protection of personnel (Exs. 3-3, 3-5, 3-6). For example, ASSE recommended that OSHA work at harmonizing this program with the assured equipment

grounding conductor program permitted under OSHA's construction standards (Ex. 3-5). ASSE did concur that OSHA's testing program in the construction standard, which requires testing after any incident that can reasonably be suspected to have caused damage, is preferable to the approach taken in NFPA 70E.

OSHA agrees with these commenters that any assured equipment grounding conductor program in the general industry standards must be consistent with the corresponding construction standard in § 1926.404(b)(1)(iii). The Agency maintains that the assured equipment grounding conductor program in the existing construction standards is more protective than NFPA's assured grounding program. OSHA's construction standard requires testing of all cord sets and receptacles whenever it can reasonably be suspected that an incident may have caused damage to the equipment, whereas the NFPA standard requires testing only if an incident produces evidence of damage. The purpose of the assured equipment grounding conductor program is designed to detect and correct damage to the equipment grounding conductor particularly when it is unseen. Demanding evidence of damage, as NFPA does, partially thwarts that purpose. Therefore, the Agency has brought the assured equipment grounding conductor program from § 1926.404(b)(1)(iii) into this revision of the general industry electrical installation standard. The final rule requires employers to use the assured equipment grounding conductor program whenever approved GFCIs are not available.

Although the assured equipment grounding conductor program in the final rule is consistent with the one in the construction standard, the final rule, unlike the construction standard, does not always permit it to be used as an alternative to GFCIs. The determination that GFCIs are a preferable form of protection and not to permit the assured equipment grounding conductor in all circumstances is based on the public record of this rulemaking. The final rule applies only to general industry and not to construction. OSHA will not enforce this rule for construction work; however, employers are encouraged to use GFCIs in accordance with the general industry standard even when the construction standard applies.

The assured equipment grounding conductor program in the construction standard relies on the definition of “competent person” in § 1926.32(f).

The assured equipment grounding conductor program in this final rule also requires one or more competent persons for implementation. Consequently, the Agency is bringing the definition of “competent person” from OSHA's construction standards into final § 1910.399.

Paragraph (f) of § 1926.32 reads as follows:

Competent person

means one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.

OSHA received numerous comments concerning proposed § 1910.304(b)(4)(ii)(A). The pertinent part of this proposed provision read, “receptacles on a 2-wire, single-phase portable or vehicle-mounted generator rated not more than 5 kW, where the circuit conductors of the generator are insulated from the generator frame and all other grounded surfaces, are permitted without ground-fault circuit-interrupter protection for personnel.” This exemption from the GFCI requirement was taken from NFPA 70E-2000.

Several commenters recommended removing this exemption (Exs. 4-13, 4-15, 4-17, 4-18, 4-21). These commenters stated that this exemption has been removed from the most recent editions of the NEC and NFPA 70E. They argued that there was never any technical justification for this provision and, thus, its inclusion in the OSHA standard is unjustified.

OSHA agrees with these comments and has decided to remove this exemption to better align the final rule with the consensus standards. The proposed exemption from the GFCI requirement for portable and vehicle-mounted generators was based on 1999 NEC Section 305-6(a), Exception 1. The exemption in the 1999 NEC and the exemption in proposed § 1910.304(b)(4)(ii)(A) were the same as the exemption for portable and vehicle-mounted generators in OSHA's construction requirement for ground-fault circuit-interrupters (§ 1926.404(b)(1)(ii)). In promulgating the construction standard, OSHA gave the following rationale for exempting these generators from the requirement for GFCI protection:

On generators whose supply wires are not required to be grounded, and are in fact not grounded, the return path for a ground-fault current to flow is not completed and the hazard which a GFCI would protect against is not present. Consequently, the rule as promulgated in [§ 1926.404(b)(1)(ii)] does not require the use of GFCI's on portable or vehicle-mounted generators of 5kW capacity or less if its output is a two-wire, single-phase system and its circuit conductors are insulated from the generator frame and all other grounded surfaces. [41 FR 55702, December 21, 1976]

The NEC used to require only neutral conductors to be bonded to the generator frame. (See, for example, 1981 NEC Section 250-6.) The NEC now requires single-phase, two-wire circuits to have one circuit conductor bonded to the generator frame. (See Sections 250-26 and 250-34(c) of the 1999 NEC and Sections 250.26 and 250.34(C) of the 2002 NEC.) Thus, the NEC no longer permits generators to be wired so as to meet the conditions in the proposed exemption. That is, because one of the circuit conductors must be bonded to the generator frame, the conductors cannot be “insulated from the generator frame” as required by the exemption.

In addition, connecting one conductor on a single-phase, two-wire generator to the generator frame facilitates the operation of a GFCI when a ground fault occurs. Even though the generator frame is not required to be grounded, it frequently is, through direct contact with ground or through grounding-type equipment, which has its equipment grounding conductor connected to the generator frame. Bonding one of the circuit conductors to the generator frame provides a path outside the circuit conductors for ground-fault current to flow. Such current will be detected by a GFCI. If the circuit conductors are insulated from the generator frame, it is more likely that any ground fault current will return through the circuit conductors and go undetected by a GFCI.

For a ground fault to occur on an ungrounded circuit, two faults must be present. If both faults are on the load side of the GFCI, then any leakage current will go undetected.

For these reasons, OSHA has determined that the exemption from the GFCI requirement for single-phase generators is not warranted and has revised final § 1910.304(b)(3)(ii)(A) (proposed § 1910.304(b)(4)(ii)(A)) accordingly. In addition, the evidence in the record indicates that it is also necessary to revise the generator grounding requirements in final § 1910.304(g)(2) and (g)(3)(iii) to match Sections 250.26 and 250.34(C) of the 2002 NEC, respectively. (See the summary and explanation of these provisions later in this section of the preamble.) Removing the exception from final § 1910.304(b)(3)(ii)(A) without revising the generator grounding provisions would result in a requirement for GFCIs when they would not work as intended to protect employees. Incorporating the NEC

provisions on generator grounding will work in concert with the GFCI provisions to ensure that employees are adequately protected from ground faults.

OSHA proposed Note 2 to § 1910.304(b)(4)(ii)(A) to read as follows:

Cord sets and devices incorporating listed ground-fault circuit-interrupter protection for personnel are acceptable forms of protection.

Several commenters suggested that the note be reworded to recognize portable GFCI protection only when it is placed at the end closest to the source of power (Exs. 4-13, 4-15, 4-17, 4-18, 4-21). They argued that GFCI protection should be provided for the entire cord set and that the only way to do so is to put the GFCI at the source of power.

The National Electrical Code Handbook for the 2002 NEC, in its explanation of the NEC requirements for GFCI protection for temporary installations, identifies a GFCI device as being designed for insertion at the line, or source, end of a flexible cord set. The short style of cord set shown in the Handbook lends itself to in-series connection with single or multiple, series-connected, cord sets.

OSHA agrees with these commenters and has revised the note to read:

Cord sets and devices incorporating the required ground-fault circuit-interrupter that are connected to the receptacle closest to the source of power are acceptable forms of protection.

This language, which was similar to that recommended by these commenters, will provide the most effective protection for employees using temporary wiring. Employers using portable GFCIs to comply with final § 1910.304(b)(3)(ii)(A) must install them at the first receptacle on the circuit (the end closest to the source of power). This will protect employees from faults in all downstream cord sets and equipment.

I. Accessibility of Overcurrent Devices

Proposed § 1910.304(f)(1)(iv) addressed the location of overcurrent devices. The first sentence of this provision would have required overcurrent devices to be accessible “to each employee or authorized building management personnel.”

OSHA received a request to insert the word “qualified” before “employee” in that provision (Ex. 4-22). The commenter was concerned that the provision would require every employee at the workplace to have access to overcurrent devices.

This proposed provision is identical to existing § 1910.304(e)(1)(iv) and is consistent with § 240.24 of the 2002 NEC. The wording of this provision permits employers to restrict access to authorized building management personnel. Consequently, the proposed rule does not require access by every employee, and there is no need to revise the language of the rule.

J. Grounding

Proposed § 1910.304(g)(1) listed systems that would have been required to be grounded. Proposed paragraphs (g)(1)(iv) and (g)(1)(v) governed grounded and ungrounded ac systems of 50 to 1000 volts. These two paragraphs were substantively the same as paragraphs (f)(1)(iv) and (f)(1)(v) of existing § 1910.304, except that in the existing rule ac circuits of 480 to 1000 volts are permitted to use a high-impedance grounded neutral in lieu of a neutral with a direct connection to the grounding electrode.

In a joint comment, CHS Inc., and the National Cooperative Refinery Association (NCRA) expressed concern about these provisions (Ex. 4-25). These two companies requested that the Agency consider permitting the operation of three-phase ungrounded delta systems that have been utilized for many years by the refining industry and others for electrical systems. They argued that these systems became popular in the early 20th century because of the need to operate loads without interruption because of the operation of overcurrent protection devices on a short circuit. The comment referenced Soares Book on Grounding published by the International Association of Electrical Inspectors. Quoting this book, the commenter stated that the reason to operate a system in this manner is to “obtain an additional degree of service continuity. Since the system is ungrounded, the occurrence of the first ground fault (as distinguished from a short circuit) on the system will not cause an overcurrent protective device to open.” CHS and NCRA further noted that these ungrounded systems are used with ground detection equipment and that trained electrical maintenance personnel investigate and repair problems without causing an abrupt outage.

Electrical systems are grounded primarily to:

(1) Limit overvoltages caused by lightning, line surges, or contact with higher voltage systems;

(2) Stabilize voltage to earth during normal operation; and

(3) Facilitate the operation of overcurrent devices protecting the circuit. (See 1999 NEC Section 250-2.)

Soares Book on Grounding, a recognized reference on grounding to which CHS and NCRA referred, offers a list of known disadvantages of operating ungrounded three-phase ac systems as follows:

Disadvantages of operating systems ungrounded include but are not limited to the following:

1. Power system overvoltages are not controlled. In some cases, these overvoltages are passed through transformers into the premises wiring system. Some common sources of overvoltages include: lightning, switching surges and contact with a high voltage system.

2. Transient overvoltages are not controlled, which, over time, may result in insulation degradation and failure.

3. System voltages above ground are not necessarily balanced or controlled.

4. Destructive arcing burnouts can result if a second fault occurs before the first fault is cleared.

An ac system that is connected for ungrounded operation is a system that is connected to ground via the capacitance of the insulating medium, be it air, rubber or thermoplastic insulation. The capacitance-to-ground varies resulting in system operating problems. The line-to-ground voltage is not constant. Such erratic voltage makes ungrounded systems difficult to troubleshoot.

OSHA views these conditions as hazardous to employees working near the power system. A hazard of this type of installation is the possibility for the frame of a piece of equipment to become energized at some voltage above ground. A shock hazard exists if an employee simultaneously touches the equipment and a grounded object such as a handrail.

In general, the NEC and the IAEI Soares Book on Grounding cite very similar if not the same recommendations for grounding of electrical s

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