Misleading Panelboard Rating

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bcnj

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I have a 480v Distribution Panel with fused switch buckets that feeds smaller 480v Panelboards throughout the facility.

A few Panelboards have a MCB that is rated higher than the fuse in the distribution panel. The wire is sized according to the fuse in the DP. Essentially the sub panels have a 100a MCB but the fuse in the DP is rated for 50a. Is there a code that doesn't allow this even though the wire is protected by the fuse?

Only issue I can think of is that the Panel gives the appearance that it can hold a higher load than it really does. The fuse would blow before the MCB trips.

Thank you


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I've been known to buy a panel with a higher ampacity main then the feeder supplying it just to get extra spaces that come standard in a panel with a higher rating. The only potential issue is the wire may be too small for the lugs in the breaker. Other than that, it's a nonissue.
 
Cow said:
I've been known to buy a panel with a higher ampacity main then the feeder supplying it just to get extra spaces that come standard in a panel with a higher rating. The only potential issue is the wire may be too small for the lugs in the breaker. Other than that, it's a nonissue.
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Not a problem. We sometimes upgrade a 200A panel (bus rating) that has a 200A main breaker to a 225A panel but keeping the 200A main breaker so that we can fit more PV into it under the 120% rule.
 
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