AC Disconnect

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Jpyote

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I got a red tag from an inspector telling me my breaker size was too small for the ac unit. The nameplate on the unit says 26.1 minimum ampacity
40ampHACR / 45AMP FUSE.
I have a 2P 30 HACR breaker with a non-fused disconnect.
This has been legal for many years has is changed and I just missed it. Inspector was 40A.on the branch circuit.
 
Re: AC Disconnect

He's correct. The breaker must comply with the nameplate rating of the unit, in this case the minimum being a 40 amp HACR.
 
Re: AC Disconnect

Does the "40ampHACR / 45AMP FUSE" say maximum protection? If not you should have used the above for sizing the breaker.
 
Re: AC Disconnect

So, what I will be doing is putting a 40A. Breaker on #10 NMB. How does this protect my wire?
 
Re: AC Disconnect

If the minimum circuit ampacity is 26.1 amps and the maximum overcurrent protection is 40/45 amps this installation is compliant.
 
Re: AC Disconnect

Originally posted by Jpyote:
So, what I will be doing is putting a 40A. Breaker on #10 NMB. How does this protect my wire?
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Your wire is protected for a ground fault though the 40A breaker and the equipment has itself contains the protection for overcurrent. You need the higher breaker ampacity for the motor startup to prevent nuisance tripping.
 
Re: AC Disconnect

JPYOTE: Ground-fault short-circuit protection is provided by the breaker or fuses, overload protection is provided by the overload relay in the compressor controls. 440.22(A)allows the breaker or fuses to be rated at 175% of the compressor load current,and in some case up to 225%. The branch circuit size is based on 440.32 at 125% of the compressor rated current. The ampacity of the circuit conductors is already provided at 26.1A.
 
Re: AC Disconnect

allenwayne - your rule of thumb is on-the -money. It works safely, meets NEC, & does not waste labor & material.
 
Re: AC Disconnect

Thanks guys for all the replies.
allenwayne your rule is the exact one that I use. Now I have to get the inspector to understand it. Some do and most in Redding, Ca. don't. Again, thanks.
 
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