In reading 110.14(C)(1) I interpret this to require the use of #1 (THWN/THHW) wire for all 100A circuits. I have often been questioned over this because most installations use #2 conductors for 100A circuits. I would appreciate comments on the proper application of this code section.
100A 60C Temperature Limitations - AWG 1 or AWG 2
- Thread starter jkmaute
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- New Jersey
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- Journeyman Electrician
#3 THHN @ 75 Degrees C=100 amps.
- Location
- Lockport, IL
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- Retired Electrical Engineer
Keep reading, but don't expect it to be clear. 
110.14(C)(1)(a)(3) essentially lets you use the 75C ampacity, if the "equipment" (generally meaning the terminations) is rated for 75C conductors.
110.14(C)(1)(a)(3) essentially lets you use the 75C ampacity, if the "equipment" (generally meaning the terminations) is rated for 75C conductors.
- Location
- Massachusetts
jkmaute said:
You are right.
But most if not all 100 amp rated equipment is provided with 75 C terminals and labeled as such.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Even at 60 degree C #2 THHN is rated for 95 amps. This can be protected at the next higher standard size which is 100 amps. The only caveat being that the connected load cannot exceed 95 amps.
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