46 CFR §111.50-5

1. (a)Location in circuit. Overcurrent devices must be at the point where the conductor to be protected receives its supply, except as follows:
   1. (1)The generator overcurrent protective device must be on the ship's service generator switchboard. (See § 111.12-11(g) for additional requirements.)
   2. (2)The overcurrent protection for the shore connection conductors must meet § 111.30-25(f).
   3. (3)If the overcurrent device that protects the larger conductors also protects the smaller conductors, an overcurrent device is not required at the supply to the smaller conductors.
   4. (4)If the overcurrent device protecting the primary side of a transformer also protects the conductors connected to the secondary side, as determined by multiplying the current-carrying capacity of the secondary conductor by the secondary to primary transformer voltage ratio, and this protection meets § 111.20-15 of this chapter, an overcurrent device is not required at the supply to the secondary side conductors.
2. (b)Location on vessel. Each overcurrent device:
   1. (1)Must be:
      1. (i)Readily accessible; and
      2. (ii)In a distribution panelboard, switchboard, motor controller, or similar enclosure; and
   2. (2)Must not be:
      1. (i)Exposed to mechanical damage; and
      2. (ii)Near an easily ignitable material or where explosive gas or vapor may accumulate.