# Question on 3phase 400 amp service



## Dennis Alwon

If this is a 400 amp service then you need to use T. 310.15(B)(2)(a) along with T. 310.16


----------



## Jdscada

Thanks, I dont have the handbook, left it somewhere, need to get another one. I was hoping someone could give actual wire size for my application, until I get a replacement.


----------



## HARRY304E

Jdscada said:


> Thanks, I dont have the handbook, left it somewhere, need to get another one. I was hoping someone could give actual wire size for my application, until I get a replacement.


You can buy the PDF for the 2011 right here..

http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70&cookie_test=1


Welcome to the forum..:thumbsup:


----------



## tgreen

from the way your question is worded, i am concerened about answering this question. a qualified journeyman should have his termanology correct.


----------



## HARRY304E

tgreen said:


> from the way your question is worded, i am concerened about answering this question. a qualified journeyman should have his termanology correct.



That why i posted a link to the code book if he is an Electrician he should be able to buy one without much trouble..


.


----------



## tgreen

If I was nice I would tell ya to use 250 for copper and 400 for alum. It will fit in a 4" but not an easy pull


----------



## nitro71

Here you go, bet they can sell you a code book :thumbsup:

*Crawford Electric Supply*









3788 E Highway 44, Alice, TX 78332-6818 (361) 661-1444 ‎


----------



## PicElec

is deregulate a new NEC term? Must of missed that in my last continuing ed class.


----------



## Cletis

*word*

I use that word all the time. Like, Hey baby, you wanna go degulate after work.


----------



## ktech

*?*

Perhaps there is someone out there who is qualified to do the job!!


----------



## Hippie

Why would you parallel conductors in the same pipe? That doesn't make a lot of sense to me


----------



## Sparky208

Hippie said:


> Why would you parallel conductors in the same pipe? That doesn't make a lot of sense to me


Sometimes if you add the price of the wire it's cheeper per foot also you save in labor easier to to work with and terminate smaller conductors but you have to "deregulate" them so sometimes it's not worth it. I have done it where it was spec that way on the print by the electrical engineer and questioned my project manger and that's what I was told. 

P.S. To the OP you should hire a EC they would have the experience and a code book to complete the job.


----------



## Jmohl

Just thinking out loud, is he talking about running tray cable in the conduit???? rather than three ind. conductors????


----------



## K2500

Jmohl said:


> Just thinking out loud, is he talking about running tray cable in the conduit???? rather than three ind. conductors????


Don't think so, but if he is than;
Good luck saving money with that idea.


----------



## Jmohl

Well I think everyone has the guy pegged as a trunk slammer anyway but if he isn't, his lack of training is showing......:blink:


----------



## oldtimer

Jmohl said:


> Well I think everyone has the guy pegged as a trunk slammer anyway but if he isn't, his lack of training is showing......:blink:


 I think he has his mords wixed (intentional).

He means *DERATE.* I think!


----------



## ktech

250cu. but why waste a wire by derating. I would run one 2 inch conduit per panel with 4- 3/0's per conduit. mucho easy


----------



## tgreen

the only reason that i would consider pulling parallel runs in the same raceway is if the raceway was existing. 
it is by far more economical to run (2) 2" conduits then it is to install (1) 4" conduit. so under a new install i would never consider running (1) 4" for this application. and if your not tooled for 4" there are even more problems, or you end up using a lot of prefab bends which makes it look perty scabby.


----------



## TundraJD

From what I'm understanding of this first off why not go to a tech cable if running parallel? This way you still keep to smaller cables but don't have to derate your cable I'm pulling in the exact same service except taking the full 400amps into my service if you do go with tech you can go with a 3/o copper or a 250kcmil aluminum of course with a #3 ground at least that coheres to CEC regulations not sure about NEC

Sent from my iPhone using ET Forum


----------



## BBQ

Hippie said:


> Why would you parallel conductors in the same pipe? That doesn't make a lot of sense to me


Sometimes it works very well cost wise even with the derating.


----------



## BBQ

tgreen said:


> the only reason that i would consider pulling parallel runs in the same raceway is if the raceway was existing.
> it is by far more economical to run (2) 2" conduits then it is to install (1) 4" conduit..


Never say never, run the numbers each time, the results can surprise you. 



TundraJD said:


> From what I'm understanding of this first off why not go to a tech cable if running parallel?


I would say because he is in Texas and the NEC does not allow 'tech cable'.


----------



## TundraJD

Is that right hey just out of question why aren't you allowed to run a teck cable as a service feeder? Like it's approved for direct burial....

Sent from my iPhone using ET Forum


----------



## Jlarson

TundraJD said:


> Is that right hey just out of question why aren't you allowed to run a teck cable as a service feeder? Like it's approved for direct burial....
> 
> Sent from my iPhone using ET Forum


It needs to be PVC jacketed MC here in the states to be NEC legit.


----------

