46 CFR 169.681 - Disconnect switches and devices.
(a) Externally operable switches or circuit breakers must be provided for motor and controller circuits and must open all ungrounded conductors of the circuit.
(b) 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.
(c) For circuits protected by fuses, the disconnect switch required for fuses in § 169.683(b) of this chapter is adequate for disconnecting the circuit from the supply.
(d) The disconnect means may be in the same enclosure with motor controllers.
(e) Disconnect means must be provided to open all conductors of generator and shore power cables.