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Hvac ocpd size question

411 Views 5 Replies 5 Participants Last post by  Etwo
Hello, I have HVAC equipment the spec says MCA 25A and MOCP 31A.

31A is not standard breaker, should I code compliant with 30A breaker?

Thanks.
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Retired EC
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Yes, your fine. I'm surprised the MCA and MOCP are so close to each other. Does this unit have a soft start or VFD?
Before I retired I saw many residential units where the mca and the max overcurrent protective device were the same. It used to be that the max ocp was 175% of the fla of the unit.
 
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Electrical contractor 37 years. Electrical inspector 2 years
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Curious, is it a Trane unit? I just hooked up a roof top unit that said " minimum circuit ampacity 44 amps" and "maximum fuse or circuit breaker 45 amps" I put a 50 amp because a 45 amp QOB is virtually non existant and I cannot get 45 amp fuses until who knows when. It seems the min and max are getting closer on the newer units.
 

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Discussion Starter · #6 ·
No it’s not a train. You are right the new unit seems to be closer to the mocp
Curious, is it a Trane unit? I just hooked up a roof top unit that said " minimum circuit ampacity 44 amps" and "maximum fuse or circuit breaker 45 amps" I put a 50 amp because a 45 amp QOB is virtually non existant and I cannot get 45 amp fuses until who knows when. It seems the min and max are getting closer on the newer units.
 
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