MCC 480v buckets

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the NEC does not have specific language about what you are asking, but 110.3(B) would be a general rule, And there is a article 409 on control panels. In Washington, a owner can modify and build control panels under an electrical permit. And MCC spare spaces are commonly used for circuit breakers, fused disconnects. You can contact the MCC mfg with the MCC serial number, they can build you a bucket, it would be listed and then you can just plug it in. If they can't supppy what you want, a panel shop can build it to order and as pointed out by b1miller.
 
A starter bucket is only one of many choices available for the space.

It can be used for a softstart, vfd, power supply, ethernet switch, feeder breaker, fused disconnect, an empty bucket, the sky is the limit almost.
 
You (or a UL508A panel shop) cannot build an MCC bucket with any power devices that would connect to the bus bars on your own and maintain the UL listing of the MCC. The UL listing of MCCs is under UL845, and there is no viable option for field assembled units, they must come from the factory. Panel shops can however make any modifications to control circuits in a factory assembled bucket under UL508A.

There is a program under UL2727 for some pre-qualified switchboard modification shops to make retrofit MCC buckets for obsolete MCCs. It is VERY expensive because of the documentation and possible testing involved. The only time I’ve seen people use this is when the gear is way too critical to abandon and hard to replace.

You can use the space, with an appropriate solid back pan and door, to house anything that is not directly connected to bus bars.
 
Jraef said:
You (or a UL508A panel shop) cannot build an MCC bucket with any power devices that would connect to the bus bars on your own and maintain the UL listing of the MCC. The UL listing of MCCs is under UL845, and there is no viable option for field assembled units, they must come from the factory. Panel shops can however make any modifications to control circuits in a factory assembled bucket under UL508A.

There is a program under UL2727 for some pre-qualified switchboard modification shops to make retrofit MCC buckets for obsolete MCCs. It is VERY expensive because of the documentation and possible testing involved. The only time I’ve seen people use this is when the gear is way too critical to abandon and hard to replace.

You can use the space, with an appropriate solid back pan and door, to house anything that is not directly connected to bus bars.
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Good point. I did not mention that we would install a solid backpan and feed the installed components from a 120V circuit breaker in the factory installed lighting panel.
 
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