sizing OCP, wiring, disc for CU - verify?

[benaround]

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]

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]

Well, there you go,,,,,,how are you gonna put that on a 30?

Well if thats how you think how are you putting a #12 on a 30 amp OCPD and please dont tell me its good for 30 amps because the 90 degree column in for derating only. (110.14 C)

 

[celtic]

The 30 amp OCPD is there for ground fault and short circuit protection not overload.

Where is the GF protection on an HACR CB?

 

[benaround]

Check 240.4 G then 440.31 refers us to 440.6 (A) Exception #1 (overload protection is the key 440 Part VI.)

IMO, thermally protected or overload protection is a given, either by the manafacture or

the installer.

 

[yired29]

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.

 

[LarryFine]

Are you implying you would put a #14 on a 30 amp breaker???

With a MCA of <20a and MOP of 30a, yes.