sizing OCP, wiring, disc for CU - verify?

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benaround

Senior Member
Location
Arizona
I don't think I have ever see a MCA rating of 13.5 amps and an OCPD of 30.


In your example #14 would suffice for the MCA,,,,,,,but could not be put on a 30 amp breaker, therefore, #12 would be needed.

I disagree, NEC says to use the manafactures nameplate for MCA and MOCP, if the MCA

is #14 wire and the Maxocp is 30a, #12 wire is not required.
 

yired29

Senior Member
I don't think I have ever see a MCA rating of 13.5 amps and an OCPD of 30.


In your example #14 would suffice for the MCA,,,,,,,but could not be put on a 30 amp breaker, therefore, #12 would be needed.
Check 240.4 G then 440.31 refers us to 440.6 (A) Exception #1 (overload protection is the key 440 Part VI.)
 

yired29

Senior Member
Where is the GF protection on an HACR CB?
A HACR breaker will trip on ground fault. A, B, or C phase to equipment or equipment ground. III. Branch-Circuit Short-Circuit and Ground-Fault Protection
440.21 General.
The provisions of Part III specify devices intended to protect the branch-circuit conductors, control apparatus, and motors in circuits supplying hermetic refrigerant motor-compressors against overcurrent due to short circuits and ground faults. They are in addition to or amendatory of the provisions of Article 240.
 
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