200 amp commercial service

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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.
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I dont mean to rain on your party but.... You may need to check to see if there is a local amendment prohibiting alum. in commercial buildings also check the plans. The engineer may have specked copper if so you are bound to follow the specks unless you get a signed and stamped letter from the engineer stating that alum. would be acceptable. Or..... the inspector is mistaken. Then ask him to show you where it is in code.
 
Dennis Alwon said:
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)
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infinity said:
What if he's using SE cable?
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Dennis Alwon said:
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.
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Sorry I quoted the wrong post. I'm asking if he could use #4/0 Al for a commercial building at 180 amps if he used SE cable?
 
One-eyed Jack said:
Tell me why you don't think SE used for an outdoor feeder does not have to comply with 334.80. 338.10(b)(4)(b) is in addition to all of the other requirements of 338. I really hope your friend in the CMP is right in changing this back. This 60 degree stuff is a pain.
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Well for exterior feeders go to art. 338.10(N)(4)(b)
4) Installation Methods for Branch Circuits and Feeders.
(a) Interior Installations. In addition to the provisions of this article, Type SE service-entrance cable used for interior wiring shall comply with the installation requirements of Part II of Article 334.
FPN: See 310.10 for temperature limitation of conductors.
(b) Exterior Installations. In addition to the provisions of this article, service-entrance cable used for feeders or branch circuits, where installed as exterior wiring, shall be installed in accordance with Part I of Article 225. The cable shall be supported in accordance with 334.30. Type USE cable installed as underground feeder and branch circuit cable shall comply with Part II of Article 340.
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Nothing here states we must use the requirements of 334 as it does in a) for interior installations. I do not see where you get that b) is in addition to all the art. of 334
 
Dennis Alwon said:
Well for exterior feeders go to art. 338.10(N)(4)(b)


Nothing here states we must use the requirements of 334 as it does in a) for interior installations. I do not see where you get that b) is in addition to all the art. of 334
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It says in addition to the provisions of "this article". Is this article not 338? (a) is in addition to this article ie 334 part II It is my understanding that all of 338 is for SE cable (b) does not exclude (a) but is in addition to. Since (a) includes 334 part II this would apply also
 
One-eyed Jack said:
It says in addition to the provisions of "this article". Is this article not 338? (a) is in addition to this article ie 334 part II It is my understanding that all of 338 is for SE cable (b) does not exclude (a) but is in addition to. Since (a) includes 334 part II this would apply also
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Sure but but a) is talking about interior installations so yes it is part of the art. but it does not apply to b) which is exterior installation. I see what you are saying but I believe your interpretation is incorrect. Why would section b) even state anything about art. 334 (it does mention 334.30 specifically) if it already covered it in section a) as you see it.

Sorry I don't buy it. The studies were done based on insulation and SE cable. This is not an issue with outdoor installations.
 
I'd support Dennis here. 338.10(B)(4) is divided into two parts (a) for interior and (b) for exterior. (a) specifically states for interior installs you refer to Part II of Art 334. (b) refers you only to support in 334.30.
 
Dennis Alwon said:
Sure but but a) is talking about interior installations so yes it is part of the art. but it does not apply to b) which is exterior installation. I see what you are saying but I believe your interpretation is incorrect. Why would section b) even state anything about art. 334 (it does mention 334.30 specifically) if it already covered it in section a) as you see it.

Sorry I don't buy it. The studies were done based on insulation and SE cable. This is not an issue with outdoor installations.
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It would be a lot smaller can of worms if they had left it like it was in 05.
Exterior service equipment to supply a sub-panel. Min cir amps 78. Feeder run on exterior of bld #2 al=OK Run in crawl space Not OK?
 
Dennis Alwon said:
Sure but but a) is talking about interior installations so yes it is part of the art. but it does not apply to b) which is exterior installation. I see what you are saying but I believe your interpretation is incorrect. Why would section b) even state anything about art. 334 (it does mention 334.30 specifically) if it already covered it in section a) as you see it.

Sorry I don't buy it. The studies were done based on insulation and SE cable. This is not an issue with outdoor installations.
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I would say because you are being given a break in the support requirement. 225 support requirements are more stringent than the support req of 334.30. 225.21 ref to 230.51 12"and 30" 334.30 12" and 54"
 
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