310.15(b)(1)(1) vs 310.15(b)(1)(2)

[Ponchik]

Besides one is for 86F and one is 104F what is the difference between the two tables? 310.15(b)(1)(1) vs 310.15(b)(1)(2)?

I have always used the 86F table. When is the 104F table used?

TIA

 

[david luchini]

Different conductor types.

See, for instance, T310.18 for conductors that would use 310.15(b)(1)(2).

 

[Deltaforce]

Besides one is for 86F and one is 104F what is the difference between the two tables? 310.15(b)(1)(1) vs 310.15(b)(1)(2)?

I have always used the 86F table. When is the 104F table used?

TIA

104F table outdoor application, free air,
single insulated cables
The two tables give different final ampacities, So not mix up

 

[ramsy]

have always used the 86F table. When is the 104F table used?

Always preferred equation 310.15(B), for a wider range of equipment, and conditions than idiot tables, and simple enough for a spreadsheet.