SER Cable 2017 NEC

[mkgrady]

I'm running a feeder from a generator to a transfer switch that will be downstream from a 100 amp CB on the generator. The cable will run a few feet through insulation. I think the prior code cycle would require using the 60 degree rating and 1/0 AL. Am I correct that I can use the 75 degree column and that #1 AL SER is good for 100 amps?

 

[Dennis Alwon]

It really depends on the length of the ser and the length it runs thru insulation. If you qualify under the article below then use 75C otherwise you must use 60C

310.15(A)
(2) Selection of Ampacity. Where more than one ampacity
applies for a given circuit length, the lowest value shall be used.
Exception: Where different ampacities apply to portions of a circuit, the
higher ampacity shall be permitted to be used if the total portion(s) of
the circuit with lower ampacity does not exceed the lesser of 3.0 m
(10 ft) or 10 percent of the total circuit.

 

[publicgood]

110.14(C)(1)(a). 100A or less 60C column. Don’t know of previous code cycle stating otherwise. #1/0.

Is this for a dwelling unit? Is this for NEC 700/701?

 

[Dennis Alwon]

110.14(C)(1)(a). 100A or less 60C column. Don’t know of previous code cycle stating otherwise. #1/0.

Is this for a dwelling unit? Is this for NEC 700/701?

110.14(C)(1)(a) only applies where the terminals are rated 60C. Most terminals are rated 75C or more so you can use 75C column

 

[electrofelon]

I believe they changed (yet again) the thermal insulation installation requirements and using at 60 degree it only applies to 10 AWG sizes and smaller.

 

[publicgood]

110.14(C)(1)(a) only applies where the terminals are rated 60C. Most terminals are rated 75C or more so you can use 75C column

If it is marked for 75C, or wire #1/0 and large, yes. Otherwise, 60C must be used. Agree that most are listed for 75C.

 

[Dennis Alwon]

I believe they changed (yet again) the thermal insulation installation requirements and using at 60 degree it only applies to 10 AWG sizes and smaller.

You are correct-- 75C is good even if the ser is in insulation.

 

[publicgood]

I believe they changed (yet again) the thermal insulation installation requirements and using at 60 degree it only applies to 10 AWG sizes and smaller.

Please provide reference - I’d like to review.

 

[mkgrady]

It really depends on the length of the ser and the length it runs thru insulation. If you qualify under the article below then use 75C otherwise you must use 60C

I find that confusing. The run is about 50 feet and the part through insulation is about 7 feet but I could reduce it to 5 feet if that mattered.

 

[electrofelon]

I find that confusing. The run is about 50 feet and the part through insulation is about 7 feet but I could reduce it to 5 feet if that mattered.

you are good with #1, insulation or not.

 

[mkgrady]

110.14(C)(1)(a). 100A or less 60C column. Don’t know of previous code cycle stating otherwise. #1/0.

Is this for a dwelling unit? Is this for NEC 700/701?

It is for a dwelling where the gen will feed the entire 200 amp main panel and use load shed features to eliminate overloading the generator

 

[mkgrady]

you are good with #1, insulation or not.

Glad to hear that. Thanks to all

 

[publicgood]

It is for a dwelling where the gen will feed the entire 200 amp main panel and use load shed features to eliminate overloading the generator

310.15(B)(7) is why I ask

 

[Dennis Alwon]

I find that confusing. The run is about 50 feet and the part through insulation is about 7 feet but I could reduce it to 5 feet if that mattered.

In the 2017 you are good to go but the 2014 Nec you would have to deal with the insulation issue

 

[infinity]

As noted it depends on the code cycle you're under. The SE ampacity requirements have changed in almost every one of the last 4 or 5 code cycles. :slaphead:

Under the 2017 you can use 75° C.