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MCA

MCA

(OP)
When the HVAC manufacturer's list MCA, minimum circuit amps, for a unit, does this number already include the 25% extra required by NEC for feeder sizing?

RE: MCA

Yes. It is included.

RE: MCA

(OP)
I do indeed, I like your answer.

RE: MCA

MCA does not necessarily include the full 25% markup on continuous load.  The manufacturer takes the evaporator fan, the condensor fan, and the compressor and adds them together.  They then add 25% for the largest motor of the group which is almost always the compressor.  This number is called the MCA.  So if you take the MCA and multiply by 80% you will not get the correct full load amps.

RE: MCA

Feeder motor loads only need to include 125% of the single largest motor supplied, not all MCA's. As mentioned in the previous post, 80% of MCA is not necessarily FLA.

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