SE-R cable

[jwjrw]

Are you talking about a feeder that feeds the entire load of the house?

Maybe him asking what size for xhhw confused me. I was thinking service riser outdoors. I now see he means a 4wire to 200a panel from a 200a disconnect outside.

 

[Dennis Alwon]

OK I'm confused I want to run a 200 amp main breaker to a 200 amp sub panel residential what size wire xhhw do i need 2008 Nec

In my opinion, the wording of the NEC states that if the feeder feeds the entire load of the dwelling then 4/0 ser would suffice. Thus T.310.15.(B)(6) is allowed even with ser on the inside of the home.

If this feeder did not feed the entire load then, IMO, you would need 300 KCM as long as the calculated load was 190 amps or less. Now try and get the 300 KCM under your resi panel lugs (most are only rated for 250KCM) and I don't believe you can even buy SER that size.

Around here they have also dropped to 150 amps but some areas are allowing 250KCM for 200 amps.

Another method is to pipe your feeder. That's what I do.

 

[augie47]

Dennis opinion is shared by 25% of the inspectors in this general area and not shared by 75% ... hence the problem.

 

[jwjrw]

In my opinion, the wording of the NEC states that if the feeder feeds the entire load of the dwelling then 4/0 ser would suffice. Thus T.310.15.(B)(6) is allowed even with ser on the inside of the home.

If this feeder did not feed the entire load then, IMO, you would need 300 KCM as long as the calculated load was 190 amps or less. Now try and get the 300 KCM under your resi panel lugs (most are only rated for 250KCM) and I don't believe you can even buy SER that size.

Around here they have also dropped to 150 amps but some areas are allowing 250KCM for 200 amps.

Another method is to pipe your feeder. That's what I do.

I had all of it right but I couldnt word it correctly. Dennis can you point me to the art where they lowered what ser is good for? Im having trouble finding it.

 

[raider1]

I had all of it right but I couldnt word it correctly. Dennis can you point me to the art where they lowered what ser is good for? Im having trouble finding it.

338.10(B)(4)(a).

This section requires the when SER cable is run as interior wiring it must comply with Part II of Article 334. It use to say except for 334.80 but that was removed in the 2008 NEC.

Therefore when SER cable is run as a feeder or branch circuit inside of a building the ampacity of the conductors is limited to the 60 degree column of Table 310.16.

Chris

 

[Dennis Alwon]

I had all of it right but I couldnt word it correctly. Dennis can you point me to the art where they lowered what ser is good for? Im having trouble finding it.

art. 338.10(B)(4)

 

[raider1]

In my opinion, the wording of the NEC states that if the feeder feeds the entire load of the dwelling then 4/0 ser would suffice. Thus T.310.15.(B)(6) is allowed even with ser on the inside of the home.

If this feeder did not feed the entire load then, IMO, you would need 300 KCM as long as the calculated load was 190 amps or less. Now try and get the 300 KCM under your resi panel lugs (most are only rated for 250KCM) and I don't believe you can even buy SER that size.

Around here they have also dropped to 150 amps but some areas are allowing 250KCM for 200 amps.

Another method is to pipe your feeder. That's what I do.

For what it is worth I agree with Dennis' interpretation of 310.15(B)(6).

Chris

 

[augie47]

obviously, for what it's worth, I don't

 

[iwire]

For what it is worth I agree with Dennis' interpretation of 310.15(B)(6).

Chris

Sorry Gus, I am going with Chris and Dennis on this.

 

[jwjrw]

In my opinion, the wording of the NEC states that if the feeder feeds the entire load of the dwelling then 4/0 ser would suffice. Thus T.310.15.(B)(6) is allowed even with ser on the inside of the home.

If this feeder did not feed the entire load then, IMO, you would need 300 KCM as long as the calculated load was 190 amps or less. Now try and get the 300 KCM under your resi panel lugs (most are only rated for 250KCM) and I don't believe you can even buy SER that size.

Around here they have also dropped to 150 amps but some areas are allowing 250KCM for 200 amps.

Another method is to pipe your feeder. That's what I do.

When you state the wording of the nec about the feeder what art are you looking at. I understand ampacity is now based off the 60deg column for ser but does something in 215 change that?

 

[Dennis Alwon]

obviously, for what it's worth, I don't

FWIW, I don't like the way it reads to me but it is pretty clear. I personally think the CMP overlooked T. 310.15(B)(6) when they wrote art. 338.10(B)(4)(a)

 

[kbsparky]

....Another method is to pipe your feeder. That's what I do.

Same here. Those new "rules" have had no effect on our installations. We can still use 4/0 type XHHW conductors...

 

[raider1]

When you state the wording of the nec about the feeder what art are you looking at. I understand ampacity is now based off the 60deg column for ser but does something in 215 change that?

The wording comes from 310.15(B)(6) and the definition of main power feeder in that section.

Chris

 

[jwjrw]

The wording comes from 310.15(B)(6) and the definition of main power feeder in that section.

Chris

I see now. Thank you.:grin:

 

[LarryFine]

I concur that a feeder that runs inside is not the same thing as interior wiring, which I believe means wiring that originates inside.

 

[LarryFine]

I personally think the CMP overlooked T. 310.15(B)(6) when they wrote art. 338.10(B)(4)(a)

Intentionally.