#2 SER rating & 4/0 URD

[JDB3]

Having a discussion with another contractor about the rating of #2 SER al. & 4/0 URD. Table 310.15(B)(7) #2 is good for 100 amps & 4/0 is good for 200 amps. But somewhere (forgot where ??), it says wire that runs through insulation, use the 60 degree column. Therefore #2 is good for 75 amps? But also, doesn't it say something about if it is on a 100 amp or larger breaker, & terminations are rated for 75 degrees, then you can use the 75 degree rating? :huh: Please help us, Thanks.......... :?

 

[Dennis Alwon]

Article 338.10(B)(4) is what you want and also 110.14 (C). Remember if the terminals and wire are rated 75C or larger then the 100 amp or smaller wire will be consider 75C not 60C

 

[JDB3]

Thanks Dennis. I will take a look at these.

 

[Dennis Alwon]

Thanks Dennis. I will take a look at these.

NP-- if you have questions after reading it we are here.:thumbsup:

 

[texie]

As Dennis said, read 338.10(B)(4) carefully and it will help you with the temperature rating. Keep in mind that Table 310.15(B)(7) only applies to a feeder that is carrying the entire load load of the residence (look at the text). If the table applies to your situation you can use the 100 amp value for #2AL in the table and disregard 338.10(B)(4).