46 CFR § 111.70-1 - General.
(a) Each motor circuit, controller, and protection must meet the requirements of ABS Steel Vessel Rules, sections 4-8-2/9.17, 4-8-3/5.7.3, 4-8-4/9.5, and 4-8-3/5; ABS MODU Rules, Part 4, Chapter 3, sections 4/7.11 and 4/7.17; or IEC 60092-301 (all three standards incorporated by reference; see 46 CFR 110.10-1), as appropriate, except for the following circuits:
(1) Each steering gear motor circuit and protection must meet part 58, subpart 58.25, of this chapter.
(2) Each propulsion motor circuit and protection must meet subpart 111.35 of this part.
(b) In ungrounded three-phase alternating current systems, only two motor-running protective devices (overload coil or heater type relay within the motor and controller) need be used in any two ungrounded conductors, except when a wye-delta or a delta-wye transformer is used.
(c) The motor disconnecting means must be an externally operable switch or circuit breaker.