Compressor and Panel Schedule MOCP

Compressor and Panel Schedule MOCP

  • Bump up to 600A

    Votes: 0 0.0%

  • Stay with 400A

    Votes: 3 100.0%
  • Total voters
    3
  • Poll closed .
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Npstewart

Senior Member
HI everyone, I had a post yesterday regarding a 50HP compressor. Per NEC the FLA on a 50HP is 143 FLA. I originally had this on a 200amp breaker but revised it to a 250A breaker for starting purposes, I also am specifying a soft motor starter. My question, does everyone agree the 250A breaker will be ok for the compressor given I dont have any manufactuers data.

Secondly, my load calculation, (not shown in attached picture), is 299.5 amps, and that is taking 125% of the compressor into account. I have a 400A MCB in this panel, with all this equipment, do you guys think I should be going to a 600A MCB? My worry is that the compressor will fire up, along with some other piece of equipment, and it will blow the MCB in the panel.

Need opinions! :) thanks
 
i think 200a was fine for the compressor, but i guess 250a is ok too. the 400cb should not blow due to in-rush current from a compressor as far as i can tell
 
I thought it was fine too, but some poople yesterday said it might not be. It was really split, I ended up going to 250A because its allowed to size the breaker for this 250% of the FLA.
 
:)But, since yesterday you also added a soft start to the picture.
With the soft start you very well may have gotten by with the 200 amp and you should have no problem with your 400 amp main as start in-rush is now not a problem.
Somewhat akin to the answer yesterday, you may find your soft-start will specify a maximum OCP on the line side and if so 110.3(B) still applies.
 
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