Feeding a Panelboard from a MCC

[spsnyder]

I have an existing medical facility where a contractor is inquiring whether a new panel can be fed from an existing Motor Conctrol Center (MCC). He has an existing 90/3 breaker in a MCC "bucket" that he's like to use to fed a panel adjacent to the MCC. He would remove the existing H-O-A and starter in the "bucket" and fed a new 100 amp panel. The new 100 amp panel will have (2) 20/3 breakers supplying power to (2) new HVAC units.

Would this be allowed by the NEC? Thank you for your assistance.

 

[templdl]

Re: Feeding a Panelboard from a MCC

No bid deal. Simple replace the MCP in the bucket with the same frame TM breaker, remove the starter and pilot devices keeping them as spare parts, etc.
I assume that the load is a simple 3ph load with the same L-L voltage as the MCC. If the lo9ad requires a neutral the MCC may not have one as most MCCs serve motor loads that don't require neutrals.

 

[templdl]

Re: Feeding a Panelboard from a MCC

One detail that I overlooked is that it is important to varify that the conductor from the stabs to the breaker are of the correct ampacity. Some MCC manufacturers will size those conductors based upon the size of the starter and not the maximum rating of the breaker that can be installed. Size #1 an #2 starter commonly are installed in the same size buckets and both commonly use a 150a frame breaker.

 

[spsnyder]

Re: Feeding a Panelboard from a MCC

That's great. Thank you very much for your help.