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-   -   Upgraded loadcenter wiring questions (http://www.diychatroom.com/f18/upgraded-loadcenter-wiring-questions-132668/)

Johnd85053 02-05-2012 02:53 PM

Upgraded loadcenter wiring questions
 
I'm upgrading my externally-mounted (NEMA 3R) loadcenter and have a couple questions regarding wire ratings. My meter box is separate from my loadcenter. In my area NEC 2008 rules are now followed (house was built about 30 yrs ago).

1) Existing service wire from meter to loadcenter is rated THW 600V. I want to replace with new THHN 600V. NEC 2008 Table 310.13(A) says THW can be used in "dry and wet" locations whereas THHN can be used in "dry and damp" locations. Is my application considered "wet" and thus THHN is not allowed? I need this clarification.

2) Existing ground wire is #4 CU stranded bare. I need to replace it so I'd like to use #4 CU solid bare. Is there any problem using solid?

3) Existing grounding electrode is a "concrete encased" house foundation type. I want to continue to use this as the *only* grounding electrode along with proper bonding to the loadcenter. My interpretation of NEC 2008 implies I don't need to add another (if I did I'd use a ground rod since any other suitable grounding system is not convenient to make connection to).

Thanks for your expert help.

Jim Port 02-05-2012 03:00 PM

Exterior locations are considered wet, even if in conduit.

The Ufer does not need to be supplemented with another electrode.

The ground can be solid or stranded.

jbfan 02-05-2012 03:01 PM

1-Most thhn wire is dual rated as thwn, and if it is outside, it is considered a wet location.

2-No problem with the solid wire.

3-Fine the way it is.

Julius793 02-05-2012 03:06 PM

Quote:

Originally Posted by Jim Port
Exterior locations are considered wet, even if in conduit.

The Ufer does not need to be supplemented with another electrode.

The ground can be solid or stranded.

I've never can across #4 solid wire do you see it often?

Jim Port 02-05-2012 03:14 PM

The supply houses carry it. Never had a problem finding it.

Johnd85053 02-05-2012 03:14 PM

So the markings on the THHN that I want to use has only "THHN" on it, not "THHN / THWN", for example. For dual rating, so I can use it in this "wet" location, don't I need to see the cable marked as such? In other words, I can not assume its dual rated unless its actually marked as such, right?

Julius793 02-05-2012 03:15 PM

Quote:

Originally Posted by Jim Port
The supply houses carry it. Never had a problem finding it.

Well never either had a problem finding it I just never looked :)

frenchelectrican 02-05-2012 03:15 PM

Quote:

Originally Posted by Julius793 (Post 845243)
I've never can across #4 solid wire do you see it often?

I have ran into from time to time but they are very hard to bend them so a tip just grab a glove when you do bend them by hand but with tight bending radius you will need a brake line bender that how I dealt with them.

Merci,
Marc

Johnd85053 02-05-2012 05:30 PM

The markings on the THHN that I want to use has only "THHN" on it, not "THHN / THWN", for example. For dual rating, so I can use it in this "wet" location, don't I need to see the cable marked as such? In other words, I can not assume its dual rated unless its actually marked as such, right?
Can someone please confirm this marking question? Thanks.

frenchelectrican 02-05-2012 05:35 PM

Quote:

Originally Posted by Johnd85053 (Post 845363)
The markings on the THHN that I want to use has only "THHN" on it, not "THHN / THWN", for example. For dual rating, so I can use it in this "wet" location, don't I need to see the cable marked as such? In other words, I can not assume its dual rated unless its actually marked as such, right?
Can someone please confirm this marking question? Thanks.

If the marking say THHN only that is used for dry location and if marked THHN/THWN then it will be dual rated conductors.

Majorty of them I have them are useally dual rated so it is not a issue but double check the marking to make sure.

Merci,
Marc


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