46 CFR §129.220

1. (a)Electrical equipment and installations must be suitable for the roll, pitch, and vibration of the vessel under way.
2. (b)All equipment, including switches, fuses, and lampholders, must be suitable for the voltage and current used.
3. (c)Receptacle outlets of the type providing a grounded pole or a specific direct-current polarity must be of a configuration that does not permit improper connection.
4. (d)Electrical equipment and circuits must be clearly marked and identified.
5. (e)Any cabinet, panel, box, or other enclosure containing more than one source of power must be fitted with a sign warning persons of this condition and identifying the circuits to be disconnected.