# 14 CFR § 27.1357: Circuit protective devices

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1357

## Section

- **Citation:** 14 CFR § 27.1357
- **Heading:** Circuit protective devices
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** September 22, 2026
- **Source:** Publisher's official text
- **Location:** Title 14—Aeronautics and Space > CHAPTER I—FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION > SUBCHAPTER C—AIRCRAFT > PART 27—AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT > Subpart F—Equipment > Electrical Systems and Equipment

## Text

(a) Protective devices, such as fuses or circuit breakers, must be installed in each electrical circuit other than—
(1) The main circuits of starter motors; and
(2) Circuits in which no hazard is presented by their omission.
(b) A protective device for a circuit essential to flight safety may not be used to protect any other circuit.
(c) Each resettable circuit protective device (“trip free” device in which the tripping mechanism cannot be overridden by the operating control) must be designed so that—
(1) A manual operation is required to restore service after trippling; and
(2) If an overload or circuit fault exists, the device will open the circuit regardless of the position of the operating control.
(d) If the ability to reset a circuit breaker or replace a fuse is essential to safety in flight, that circuit breaker or fuse must be located and identified so that it can be readily reset or replaced in flight.
(e) If fuses are used, there must be one spare of each rating, or 50 percent spare fuses of each rating, whichever is greater.
(Secs. 313(a), 601, 603, 604, and 605 of the Federal Aviation Act of 1958 (49 U.S.C. 1354(a), 1421, 1423, 1424, and 1425); and sec. 6(c) of the Dept. of Transportation Act (49 U.S.C. 1655(c)))
[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964; 29 FR 17885, Dec. 17, 1964, as amended by Amdt. 27-13, 42 FR 36972, July 18, 1977]

## Nearby sections

- [14 CFR § 27.1301 § 27.1301 Function and installation.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1301.md)
- [14 CFR § 27.1303 § 27.1303 Flight and navigation instruments.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1303.md)
- [14 CFR § 27.1305 § 27.1305 Powerplant instruments.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1305.md)
- [14 CFR § 27.1307 § 27.1307 Miscellaneous equipment.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1307.md)
- [14 CFR § 27.1309 § 27.1309 Equipment, systems, and installations.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1309.md)
- [14 CFR § 27.1316 § 27.1316 Electrical and electronic system lightning protection.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1316.md)
- [14 CFR § 27.1317 § 27.1317 High-intensity Radiated Fields (HIRF) Protection.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1317.md)
- [14 CFR § 27.1321 § 27.1321 Arrangement and visibility.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1321.md)
- [14 CFR § 27.1322 § 27.1322 Warning, caution, and advisory lights.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1322.md)
- [14 CFR § 27.1323 § 27.1323 Airspeed indicating system.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1323.md)
- [14 CFR § 27.1325 § 27.1325 Static pressure systems.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1325.md)
- [14 CFR § 27.1327 § 27.1327 Magnetic direction indicator.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1327.md)
- [14 CFR § 27.1329 § 27.1329 Automatic pilot and flight guidance system.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1329.md)
- [14 CFR § 27.1337 § 27.1337 Powerplant instruments.](https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1337.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/ecfr-14-27.1357. Check the current official text before relying on it. Not legal advice.