CFR > Title 46 - Shipping > CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY > SUBCHAPTER L—OFFSHORE SUPPLY VESSELS (parts 125 to 135) > PART 129—ELECTRICAL INSTALLATIONS > SUBPART C—Power Sources and Distribution Systems (§129.310 to §129.395) > 129.310—Power sources.

129.310—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 at least two sources of electricity:
(i) Any system identified as a vital system in § 128.130(a) of this subchapter.
(ii) Interior lights.
(iii) Communication systems.
(iv) Navigational equipment and lights.
(v) Fire-protection equipment.
(2) A vessel with batteries of enough capacity for 3 hours of continuous operation to supply the loads specified in paragraph (a)(1) of this section, and with a generator or alternator driven by a propulsion engine, complies with paragraph (a)(1) of this section.
(b) Where a generator driven by a propulsion engine is used as a source of electrical power, no speed change, throttle movement, or change in direction of the propeller shaft of the vessel may interrupt power to any of the loads specified in paragraph (a)(1) of this section.