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UL 508A Supply Ratings

UL 508A Supply Ratings

UL 508A Supply Ratings

I am designing a switchboard panel with two NSJ600 Schneider Electric 600A circuit breakers, bonded neutral, and bus bar system to meet UL's 508A standard. I am having problems determining the ratings for the input terminals as per section 49.

49.1 The input terminals intended to be connected to each source of supply shall be rated in volts, total
full-load amperes, ampere or horsepower rating of the largest motor (when multiple loads are controlled),
number of phases when other than single phase, and the frequency.

49.2 The full-load ampere rating of the panel shall, at a minimum, include the sum of the ampere ratings
of all loads that are able to be operated simultaneously plus the primary ampere rating of all control
transformers connected to the input voltage.

These panels are intended to be stocked and sold for various applications. Since there is no way to determine the loads connected to the panel how do I find my full load ampere rating?

RE: UL 508A Supply Ratings

Looks like 2x the peak current the NSJ600 can handle, plus some margin. You don't want your panel to go up in smoke before the breaker trips.


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