200 amp commercial service

Status
Not open for further replies.
J

jm1843

Member
What size service entrance conductors would be required for 200 amp commercial service?copper or aluminum?
 
What would you say they should be and how did you arrive at the answer?

Roger
 
If the calculated load was 200 amps you would need at least ?? copper or ?? AL.

If the calculated load was less you might be able to roll down the AL a bit.
 
Last edited:
Welcome to the forum.:)

This sounds like a homework question, is that correct?

Typcially we won't give you an answer to a homework or test question, but we will help you find the answer on your own.

Tell us what you think the service entrance conductor size should be.

Chris
 
200 amp commercial service

i forgot to mention that i am coming from a meter/disco outside and hitting a panel about 50 ft away.Looking at table 310.16;for copper-4/0 and for aluminum 300's.
 
jm1843 said:
i forgot to mention that i am coming from a meter/disco outside and hitting a panel about 50 ft away.Looking at table 310.16;for copper-4/0 and for aluminum 300's.
Click to expand...
Well, we normally assume 75C wire so I am guessing you are not using 75C. Is this correct?
 
200 amp commercial service

Dennis, i plan on using conductors rated for 75c...looking at table 310.16;i am looking at 3/0-copper and aluminum 250's.Am i missing anything?
 
jm1843 said:
Dennis, i plan on using conductors rated for 75c...looking at table 310.16;i am looking at 3/0-copper and aluminum 250's.Am i missing anything?
Click to expand...


That's better but you stated 4/0 above and 3/0 copper is all you need. Also if your calculated load is less than 180 amps then you can use 4/0 alum . This is done using art. 240.4(B)
 
200 amp commercial service

Thanks Dennis,i appreciate your help.I have only been confused because the local inspector told me i could not use 4/0 al in a commercial building.I plan on doing a load calc to prove to him that i can indeed use the 4/0 al xhhw.
 
jm1843 said:
Thanks Dennis,i appreciate your help.I have only been confused because the local inspector told me i could not use 4/0 al in a commercial building.I plan on doing a load calc to prove to him that i can indeed use the 4/0 al xhhw.
Click to expand...

You are welcome

I don't understand the thinking about commercial vs residential. He is thinking this because of Table 310.15(B)(6) which allows 4/0 alum for resi. The problem is he is not looking at 240.4(B).

Now if you want a true 200 amp service -- a service capable of 200 amps, then you would have to use 250Kcm aluminum.
 
Dennis Alwon said:
You are welcome

I don't understand the thinking about commercial vs residential. He is thinking this because of Table 310.15(B)(6) which allows 4/0 alum for resi. The problem is he is not looking at 240.4(B).

Now if you want a true 200 amp service -- a service capable of 200 amps, then you would have to use 250Kcm aluminum.
Click to expand...

What if he's using SE cable?
 
mike107 said:
You guys can be tough on a novice.
Click to expand...

It's tough to walk a novice through a job on the internet. Also, in my state, the test is based on the ability to use a code book. They don't care if you don't remember all the codes...they just care that you know how to look up the needed information.

This question was all about knowing how to look up the needed information.
 
infinity said:
What if he's using SE cable?
Click to expand...
Trevor, I am one of those who believes T310.15(B)(6) supercedes art. 338. The Tables allow se cable in the heading so I think it is good if it carries the entire load of the dwelling. Now do I think it may have been overlooked--- Yes but as it reads I say SE cable is okay.

I have a friend who is working closely with the cmp on the 2011 who believes strongly that SE cable will go back to the way it was. I am not so sure.
 
Status
Not open for further replies.
Top