test question neutral reduction range

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Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
A branch ciruit supplies a household electric range with a demand factor of 8000 watts. The ungrounded conductors have an ampacity of 40 amps. The neutral ampacity must be at least:
40. 28. 35. 24

My confusion is 220.61 says the 70 percent is based on the load but the correct answer is based on the ungrounded conductor ampacity... What do you think?
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
Your right ray. I was in the wrong section. Since the demand of the range is 8000 the actual rating of the range has to be over 8.75kw.
I should have been in 210.19(A)(3) ex 2.

Reading through that secion makes it a little clearer stating the neutral conductor should be based on 70% of the OCPD. The question just gives the ampacity of the ungrounded conductors but I guess it should be used not the load.

The correct answer given is 28.
 
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