# 46 C.F.R. § 143.565 (2026): Electrical overcurrent protection other than generators and motors

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_565

## Section

- **Citation:** 46 C.F.R. § 143.565 (2026)
- **Heading:** Electrical overcurrent protection other than generators and motors
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Title 46 CFR: Shipping / Chapter I: COAST GUARD, DEPARTMENT OF HOMELAND SECURITY / Part 143: MACHINERY AND ELECTRICAL SYSTEMS AND EQUIPMENT / Subpart C: Requirements for New Towing Vessels / § 143.565: § 143.565   Electrical overcurrent protection other than generators and motors.

## Text

(a)
General requirement.
Power and lighting circuits on towing vessels must be protected by suitable overcurrent protection.
(b)
Specific requirements.
(1) Cable and wiring used in power and lighting circuits must have overcurrent protection that opens the circuit at the standard setting closest to 80 percent of the manufacturer's listed ampacity. Overcurrent protection setting exceptions allowed by NFPA's National Electrical Code (NEC), Article 240 (incorporated by reference, see § 136.112 of this subchapter) may be employed.
(2) If the manufacturer's listed ampacity is not known, tables referenced in Article 310.15(B) of the NEC (incorporated by reference, see § 136.112 of this subchapter) must be used, assuming a temperature rating of 75 °C and an assumed temperature of 50 °C for machinery spaces and 40 °C for other spaces.
(3) Overcurrent protection devices must be installed in a manner that will not open the path to ground in a circuit; only ungrounded conductors must be protected. Overcurrent protection must be coordinated such that an overcurrent situation is cleared by the circuit breaker or fuse nearest to the fault.
(4) Each transformer must have protection against overcurrent that meets Article 450 of the NEC (incorporated by reference, see § 136.112 of this subchapter).
(5) On a towing vessel, other than an excepted vessel as defined in § 136.110 of this subchapter, essential systems and non-essential systems must not be on the same circuit or share the same overcurrent protective device.

## Nearby sections

- [46 C.F.R. § 143.500 (2026) § 143.500   Applicability.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_500.md)
- [46 C.F.R. § 143.510 (2026) § 143.510   Verification of compliance with design standards.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_510.md)
- [46 C.F.R. § 143.515 (2026) § 143.515   Towing vessels built to recognized classification society rules.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_515.md)
- [46 C.F.R. § 143.520 (2026) § 143.520   Towing vessels built to American Boat and Yacht Council standards.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_520.md)
- [46 C.F.R. § 143.540 (2026) § 143.540   Pumps, pipes, valves, and fittings for essential systems.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_540.md)
- [46 C.F.R. § 143.545 (2026) § 143.545   Pressure vessels.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_545.md)
- [46 C.F.R. § 143.550 (2026) § 143.550   Steering systems.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_550.md)
- [46 C.F.R. § 143.555 (2026) § 143.555   Electrical power sources, generators, and motors.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_555.md)
- [46 C.F.R. § 143.560 (2026) § 143.560   Electrical distribution panels and switchboards.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_560.md)
- [46 C.F.R. § 143.565 (2026) § 143.565   Electrical overcurrent protection other than generators and motors.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_565.md)
- [46 C.F.R. § 143.570 (2026) § 143.570   Electrical grounding and ground detection.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_570.md)
- [46 C.F.R. § 143.575 (2026) § 143.575   Electrical conductors, connections, and equipment.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_575.md)
- [46 C.F.R. § 143.580 (2026) § 143.580   Alternative electrical installations.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_580.md)
- [46 C.F.R. § 143.585 (2026) § 143.585   General requirements for propulsion, steering, and related controls on vessels that move tank barges carrying oil or hazardous material in bulk.](https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_585.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/CFR_T46_P143_S143_565. Check the current official text before relying on it. Not legal advice.