---
kind: "section"
citation: "46 C.F.R. § 120.310"
title: "46"
number: "120.310"
heading: "Power sources."
url: "https://uscodex.org/cfr/46/120.310"
---

# §120.310. Power sources.

- (a)
  - (1) Each vessel that relies on electricity to power the following loads must be arranged so that the loads can be energized from two sources of electricity:
    - (i) The vital systems listed in [§ 119.710](/cfr/46/119.710.md) of this chapter;
    - (ii) Interior lighting except for decorative lights;
    - (iii) Communication systems including a public address system required under [§ 121.610](/cfr/46/121.610.md) of this chapter; and
    - (iv) **Navigation equipment and lights.**
  - (2) Except as provided in [§ 120.312](/cfr/46/120.312.md) of this part, a vessel with batteries of adequate capacity to supply the loads specified in [paragraph (a)(1)](#a-1) of this section for three hours, and a generator or alternator driven by a propulsion engine, complies with the requirement in [paragraph (a)(1)](#a-1) of this section.
- (b) Where a ship service generator driven by a propulsion engine is used as a source of electrical power, a vessel speed change, throttle movement or change in direction of the propeller shaft rotation must not interrupt power to any of the loads specified in [paragraph (a)(1)](#a-1) of this section.

## Notes

### 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 928, Jan. 10, 1996, unless otherwise noted.