SER Aluminum amperage

[electricguy61]

I'm looking to the forum collective wisdom on this:

What is the rating of 4-4-4-6 SER Aluminum for feeding a sub-panel? 75 degree rating is 65amps, next breaker size up is 70 amps

What's the rating of 1/0-1/0-1/0-2 SER Aluminum for feeding a sub-panel? 75 degree rating 120amps, next breaker size is 125 amps.

This is based on the breakers and panels being rated for 75 degrees

Is this your understanding? Please correct me if I'm wrong.

Thanks folks

 

[jimport]

Depending on the code cycle adopted you need to use the 60 degree column ampacities.

 

[cadpoint]

If you go here

http://www.southwire.com/products/ALSEUSEROEM.htm

At the bottom of the page is product specifications that list all the various products.

Data sheet is 2005 note * at top of chart read * at the bottom

 

[raider1]

I'm looking to the forum collective wisdom on this:

What is the rating of 4-4-4-6 SER Aluminum for feeding a sub-panel? 75 degree rating is 65amps, next breaker size up is 70 amps

What's the rating of 1/0-1/0-1/0-2 SER Aluminum for feeding a sub-panel? 75 degree rating 120amps, next breaker size is 125 amps.

This is based on the breakers and panels being rated for 75 degrees

Is this your understanding? Please correct me if I'm wrong.

Thanks folks

As already noted the 2008 NEC requires that SER cable installed as inside branch circuits and feeders are required to be installed in accordance with Part II of Article 334 including 334.80 which limits the ampacity of the SER cable to the 60 degree column of 310.16. (See 338.10(B)(4)(a))

Now the 2011 modified this by allowing the use of the 75 degree column if the SER cable is not installed in direct contact with thermal insulation.

Chris

 

[pete m.]

Now the 2011 modified this by allowing the use of the 75 degree column if the SER cable is not installed in direct contact with thermal insulation.

Chris

Since 338.10(B)(4)(a) makes no mention of minimum or maximum length that the cable would be in thermal insulation I would think that 310.15(A)(2) exception could be used if only a short section of the cable were in the insulation. Without the applicability of the exception if the SE cable only passed through 6 inches of insulation the whole run would still be limited to the 60 degree ampacity.

Am I thinking correctly on this?

Pete

 

[raider1]

Since 338.10(B)(4)(a) makes no mention of minimum or maximum length that the cable would be in thermal insulation I would think that 310.15(A)(2) exception could be used if only a short section of the cable were in the insulation. Without the applicability of the exception if the SE cable only passed through 6 inches of insulation the whole run would still be limited to the 60 degree ampacity.

Am I thinking correctly on this?

Pete

Pete, I would agree with that.

Chris

 

[infinity]

Since 338.10(B)(4)(a) makes no mention of minimum or maximum length that the cable would be in thermal insulation I would think that 310.15(A)(2) exception could be used if only a short section of the cable were in the insulation. Without the applicability of the exception if the SE cable only passed through 6 inches of insulation the whole run would still be limited to the 60 degree ampacity.

Am I thinking correctly on this?

Pete

I would agree also. That wold be the purpose of that exception where the lower ampacity of a portion of the conductor can be omitted when it falls within the parameters of the exception.

 

[ceb58]

Since 338.10(B)(4)(a) makes no mention of minimum or maximum length that the cable would be in thermal insulation I would think that 310.15(A)(2) exception could be used if only a short section of the cable were in the insulation. Without the applicability of the exception if the SE cable only passed through 6 inches of insulation the whole run would still be limited to the 60 degree ampacity.

Am I thinking correctly on this?

Pete

And I agree there is no mention of length but in talking with our state code enforcement officials they are going to hold to the fact that if the cable passes through even 1 foot of insulation it will be held to the 60 deg. rating.

 

[pete m.]

And I agree there is no mention of length but in talking with our state code enforcement officials they are going to hold to the fact that if the cable passes through even 1 foot of insulation it will be held to the 60 deg. rating.

I suppose they can do that if they adopt it as a revision to the exception or just delete the exception completely.

Pete

 

[electricguy61]

Thanks for the help folks. 338.10.B4(a) was the reference I was looking for.

I will need to educate the supply house, as I tried to explain to the manager that I thought it was limited to the 60 degree column and they disagreed. I'm sure Palo Alto will keep to the Code.

Thanks again.

 

[infinity]

And I agree there is no mention of length but in talking with our state code enforcement officials they are going to hold to the fact that if the cable passes through even 1 foot of insulation it will be held to the 60 deg. rating.

So they have a local amendment that removes the exception from the NEC or do they just provide some selective enforcement?