60amp Feeder

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Strahan

Strahan

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Location
Watsontown, PA
I want to run a 60amp feeder from existing main panel to a "sub panel". Non-continuous load size to 100%. 110.14(c)(1) points me to size according to 60c column which sizes it to a 4AWG. Now digging deeper in 110.14(c)(1) my 60amp breaker is listed as 60/75 on terminals so can I size my wire to 6AWG?

With all that I'm now at 334.80 because I want to run cable. I'm hung up here because this also points me to 60c column unless proper spacing is provided. The "sub panel" will only be about 15' away and the feeder cable will be run by itself. The more I dig the deeper in confusion I get. I think I can size it to 6AWG any thoughts?
 
At 60? C NM cable is only good for 55 amps but that with a 60 amp OCPD according to the next size up rule in 240.4 but your load would have to be 55 amps or less. You could use MC cable or another wiring method (i.e.-conduit and wire) with 75? C conductors where the ampacity would be 65 amps.
 
infinity said:
At 60? C NM cable is only good for 55 amps but that with a 60 amp OCPD according to the next size up rule in 240.4 but your load would have to be 55 amps or less. You could use MC cable or another wiring method (i.e.-conduit and wire) with 75? C conductors where the ampacity would be 65 amps.
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That is my answer as well.
Is your load over 55 sum of non continuous plus 125% continuous?
 
kwired said:
That is my answer as well.
Is your load over 55 sum of non continuous plus 125% continuous?
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No. Load wise I will be fine. Just 4 15amp lighting circuits. Thanks for the answers guys. I was originally going with the 60 column but got confused with334.80 spacing wording.
 
Strahan said:
No. Load wise I will be fine. Just 4 15amp lighting circuits. Thanks for the answers guys. I was originally going with the 60 column but got confused with334.80 spacing wording.
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Just remember that when working with NM-B Cable you are always going to be limited to the 60 degree column for the END RESULT, but you can use the 90 degree column for adjustment and correction purposes. Just as long as the your final derated value does not exceed that within the 60 degree column. The spacing just brings in another variable to be considered in 310.15(B)(3)(a).(those are the adjustments mentioned in the first sentence)
 
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