---
kind: "section"
citation: "46 C.F.R. § 183.380"
title: "46"
number: "183.380"
heading: "Overcurrent protection."
url: "https://uscodex.org/cfr/46/183.380"
---

# §183.380. Overcurrent protection.

- (a) Overcurrent protection must be provided for each ungrounded conductor for the purpose of opening the electric circuit if the current reaches a value that causes an excessive or dangerous temperature in the conductor or conductor insulation.
- (b) The grounded conductor of a circuit must not be disconnected by a switch or circuit breaker, unless the ungrounded conductors are simultaneously disconnected.
- (c) A conductor of a control, interlock, or indicator circuit, such as a conductor for an instrument, pilot light, ground detector light, or potential transformer, must be protected by an overcurrent device.
- (d) Conductors must be protected in accordance with their current carrying capacities. If the allowable current carrying capacity does not correspond to a standard device size, the next larger overcurrent device may be used provided it does not exceed 150 percent of the conductor current carrying capacity.
- (e) Steering gear control system circuits must be protected against short circuit.
- (f) Each steering gear feeder circuit must be protected by a circuit breaker that meets the requirements of [§ 58.25-55](/cfr/46/58.25-55.md) in subchapter F of this chapter.
- (g) Each lighting branch circuit must be protected against overcurrent either by fuses or circuit breakers rated at not more than 30 amperes.
- (h) Overcurrent devices capable of carrying the starting current of the motor must be installed to protect motors, motor conductors, and control apparatus against:
  - (1) Overcurrent due to short circuits or ground faults; and
  - (2) Overload due to motor running overcurrent, in accordance with [§ 111.70-1](/cfr/46/111.70-1.md) in subchapter J of this chapter. A protective device integral with the motor, which is responsive to both motor current and temperature, may be used.
- (i) An emergency switch must be provided in the normally ungrounded main supply conductor from a battery. The switch must be accessible and located as close to the battery as practicable.
- (j) Disconnect means must be provided on the supply side of and adjacent to all fuses for the purpose of de-energizing the fuses for inspection and maintenance purposes.
- (k) If the disconnect means is not within sight of the equipment that the circuit supplies, means must be provided for locking the disconnect device in the open position.
- (l) Fuses must be of the cartridge type only and be listed by Underwriters Laboratories or another independent laboratory recognized by the Commandant.
- (m) Each circuit breaker must meet UL 489 (incorporated by reference; see [46 CFR 175.600](/cfr/46/175.600.md)) or other standard specified by the Commandant, and be of the manually reset type designed for:
  - (1) Inverse time delay;
  - (2) Instantaneous short circuit protection; and
  - (3) **Switching duty if the breaker is used as a switch.**
- (n) Each circuit breaker must indicate whether it is in the open or closed position.

## Notes

### Amendments

[CGD 85-080, 61 FR 997, Jan. 10, 1996, as amended by CGD 97-057, 62 FR 51050, Sept. 30, 1997; USCG-2002-13058, 67 FR 61279, Sept. 30, 2002; USCG-2003-16630, 73 FR 65210, Oct. 31, 2008]

### Authority

Authority: 46 U.S.C. 2103, 3306; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; Department of Homeland Security Delegation No. 0170.1.

### Source

Source: CGD 85-080, 61 FR 997, Jan. 10, 1996, unless otherwise noted.

### Amendments

[CGD 85-080, 61 FR 997, Jan. 10, 1996, as amended by CGD 97-057, 62 FR 51050, Sept. 30, 1997; USCG-2002-13058, 67 FR 61279, Sept. 30, 2002; USCG-2003-16630, 73 FR 65210, Oct. 31, 2008]