Re: 480V Power Receptacles
210.3 Rating.
NEC:
Branch circuits recognized by this article shall be rated in accordance with the maximum permitted ampere rating or setting of the overcurrent device. The rating for other than individual branch circuits shall be 15, 20, 30, 40, and 50 amperes. Where conductors of higher ampacity are used for any reason, the ampere rating or setting of the specified overcurrent device shall determine the circuit rating.
Handbook commentary:
To compensate for voltage drop in a long circuit, larger conductors with a higher ampacity are commonly used. For example, a branch circuit of 10 AWG, Type TW copper conductors has a 30-ampere ampacity. However, if a 20-ampere overcurrent device protects this branch circuit, it is rated as a 20-ampere branch circuit
NEC.
Exception: Multioutlet branch circuits greater than 50 amperes shall be permitted to supply nonlighting outlet loads on industrial premises where conditions of maintenance and supervision ensure that only qualified persons service the equipment.
Handbook commentary:
It is common in industrial establishments to provide several single receptacles of 50-ampere or higher rating on a single branch circuit to allow quick relocation of equipment for production and/or maintenance use, such as in the case of electric welders. Generally, only one piece of equipment is operated at a time. The type of receptacle used in this situation is generally a configuration known as a pin-and-sleeve receptacle, although the Code does not so limit the design. Pin-and-sleeve receptacles may or may not be horsepower rated.
Andrew:
The conductors to the fused disconnects would be feeders, the conductors between the fused disconnect and 60 amp rec. would be the branch circuit.
NEC:
215.2 Minimum Rating and Size.
(A) Feeders Not More Than 600 Volts.
(1) General. Feeder conductors shall have an ampacity not less than required to supply the load as computed in Parts II, III, and IV of Article 220. The minimum feeder-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load.
