jwelectric
Senior Member
- Location
- North Carolina
Based on statements read in this forum I wasn?t sure how to answer the following question ask by a student so I ask the DOI in Raleigh.
Mitch,
I have a question about feeders for a outside AC unit.
This is how I answered this question.
430.62 Rating or Setting ? Motor Load.
(A) Specific Load. A feeder supplying a specific fixed motor load(s) and consisting of conductor sizes based on 430.24 shall be provided with a protective device having a rating or setting not greater than the largest rating or setting of the branch-circuit short-circuit and ground-fault protective device for any motor supplied by the feeder [based on the maximum permitted value for the specific type of a protective device in accordance with 430.52, or 440.22(A) for hermetic refrigerant motor-compressors], plus the sum of the full-load currents of the other motors of the group.
Using this section of the code I made the statement that the conductors between the breaker in the panel and the required fused disconnect at the unit could be the same as marked on the unit.
After thinking about my answer I though it would be a good idea to ask for help.
The Min.Cir. Amp marked on the unit is 17 amps but it is also marked with Max Fuse Size 40 amps.
#12 is isntalled from the panel to the outside fused disconnect.
My question is;
being that the conductors from the breaker to the disconnect are feeders will they be required to sized to 40 amps?
Thanks
Mike Whitt
Here is the reply I got from the DOI in Raleigh.
Mike, your basic answer is correct, but to clarify one must look at 240.4 (D) rules for small conductors. Which tells you that the rules apply except when used as in 240.4 (E) and (G) which includes A/C and refrigeration 440 parts 3 and 6.
So in the case you described #12 AWG would meet the requirements of the NC Electrical Code.
Thanks
I thought it might be good to pass it along to this thread as a lot of the members are located in the great state of NC.
Mitch,
I have a question about feeders for a outside AC unit.
This is how I answered this question.
430.62 Rating or Setting ? Motor Load.
(A) Specific Load. A feeder supplying a specific fixed motor load(s) and consisting of conductor sizes based on 430.24 shall be provided with a protective device having a rating or setting not greater than the largest rating or setting of the branch-circuit short-circuit and ground-fault protective device for any motor supplied by the feeder [based on the maximum permitted value for the specific type of a protective device in accordance with 430.52, or 440.22(A) for hermetic refrigerant motor-compressors], plus the sum of the full-load currents of the other motors of the group.
Using this section of the code I made the statement that the conductors between the breaker in the panel and the required fused disconnect at the unit could be the same as marked on the unit.
After thinking about my answer I though it would be a good idea to ask for help.
The Min.Cir. Amp marked on the unit is 17 amps but it is also marked with Max Fuse Size 40 amps.
#12 is isntalled from the panel to the outside fused disconnect.
My question is;
being that the conductors from the breaker to the disconnect are feeders will they be required to sized to 40 amps?
Thanks
Mike Whitt
Here is the reply I got from the DOI in Raleigh.
Mike, your basic answer is correct, but to clarify one must look at 240.4 (D) rules for small conductors. Which tells you that the rules apply except when used as in 240.4 (E) and (G) which includes A/C and refrigeration 440 parts 3 and 6.
So in the case you described #12 AWG would meet the requirements of the NC Electrical Code.
Thanks
I thought it might be good to pass it along to this thread as a lot of the members are located in the great state of NC.