Is USE Cable permitted to terminate in interior panel?

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electriglide

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Master electrician
Hey guys just need some conformation on article 338.12 B
Can USE cable ran in pvc raceway be terminated in a sub panel located inside a residence? The pipe comes up thru the slab about 4ft and into the panel. I interpret 338.12B 2 as saying it must terminate in an exterior j box and then maybe use SE cable or other type of wire to enter the building.
Thanks in advance for any clarification. I haven't done a lot of residential wiring in the past.
 
But if it is not dual rated, even the short stub-up inside the building and the presence of the wire in the panel would be a violation, and your suggested alternatives would be necessary.
 
Same response as others. My inspector didn't like even 4' of USE in pipe from slab. Didn't make me change it but subsequent installs were xhhw.
 
LarryFine said:
Welcome to the forum.

Yes, if the conductors are dual-rated as RHW also, for example.
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Hey Larry, how can I tell if the cable is dual rated, will it have use-2/RHW written on the insulation?
The wire iam concerned about has type USE-2 written on the insulation and , xlpe- this being the type of insulation if iam correct.
The residence owner wants me to use it as a underground feeder, in pvc conduit from the service panel in his garage, to feed a 100 amp sub panel in a pool house.
 
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farmantenna said:
Same response as others. My inspector didn't like even 4' of USE in pipe from slab. Didn't make me change it but subsequent installs were xhhw.
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Thanks for the reply, it's one of those things we're your pretty sure it's wrong but you just want verification.
 
electriglide said:
Hey Larry, how can I tell if the cable is dual rated, will it have use-2/RHW written on the insulation?
The wire iam concerned about has type USE-2 written on the insulation and , xlpe- this being the type of insulation if iam correct.
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Yes, you're good. XLPE = cross-linked polyethylene. RHW was just an example.
 
FWIW : Conductors marked USE-XLPE only would not be acceptable locally for interior use. XLPE, as noted, is a type insulation and is not a 310.104 listed conductor.
 
augie47 said:
FWIW : Conductors marked USE-XLPE only would not be acceptable locally for interior use. XLPE, as noted, is a type insulation and is not a 310.104 listed conductor.
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This is where it gets confusing. The code says not to use USE-2 in interior spaces. It doesn't mention dual ratings. It doesn't say it's OK if terminating in a panel. But I have heard and read in different articles on the web that say that both circumstances are OK. I guess the best thing to do is Check with the local inspector seeing he would have the final approval.
 
electriglide said:
This is where it gets confusing. The code says not to use USE-2 in interior spaces. It doesn't mention dual ratings. It doesn't say it's OK if terminating in a panel. But I have heard and read in different articles on the web that say that both circumstances are OK. I guess the best thing to do is Check with the local inspector seeing he would have the final approval.
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When there is more than one rating you can use any of those ratings for your application.

Another common example that many never pay much attention to is "THHN". Most of it we see today has more than one rating on it. THHN, THWN, THWN-2 in particular. If it were only marked THHN you can not use it in wet locations, it would need to be THWN. Since it is marked with both you never think about it and no inspector ever rejects it so even more reason to not think about it.
 
augie47 said:
FWIW : Conductors marked USE-XLPE only would not be acceptable locally for interior use. XLPE, as noted, is a type insulation and is not a 310.104 listed conductor.
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XHHW is also a cross linked polyethylene material, but by design has different smoke and flame producing characteristics than that of a straight USE rated conductor and is reason they can be used indoors to the best of my knowledge.
 
kwired said:
When there is more than one rating you can use any of those ratings for your application.

Another common example that many never pay much attention to is "THHN". Most of it we see today has more than one rating on it. THHN, THWN, THWN-2 in particular. If it were only marked THHN you can not use it in wet locations, it would need to be THWN. Since it is marked with both you never think about it and no inspector ever rejects it so even more reason to not think about it.
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I agree with your evaluation but is there somewhere in the code that states this. Also in 310-104 A. I do not see any designation for xlpe I guess iam trying to make the code all inclusive,, is this a case where you have to look at the cables UL listing to verify it proper usage?
 
electriglide said:
I agree with your evaluation but is there somewhere in the code that states this. Also in 310-104 A. I do not see any designation for xlpe I guess iam trying to make the code all inclusive,, is this a case where you have to look at the cables UL listing to verify it proper usage?
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I am not aware of anyplace in code that tells just exactly what XLPE (cross linked polyethylene) is. It is more of a generic term, is a plastic type that is used for more than just electrical insulation, PEX water piping is also XPLE based plastic.

Some the conductors in 310.104(A) are XLPE types. Those that are say thermoset in the first column - particularly the XHH, XHHN, XHHW types.

The other most common types used TW, THW, THHN, THWN and other variations of these all say thermoplastic in that first column and are PVC based plastics.

USE in that table doesn't designate what the insulation material is. A conductor that only has that rating could be anything that meets the listing standards, but may not meet other standards for other conductor types.

Conductor marked USE as well as other types- meets the criteria for every marking it has on it.
 
augie47 said:
FWIW : Conductors marked USE-XLPE only would not be acceptable locally for interior use. XLPE, as noted, is a type insulation and is not a 310.104 listed conductor.
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Same position I’m in lol and augie knows
 
electrofelon said:
I agree that "XLPE" is meaningless per the NEC and this gets you nothing. Conductors marked only "USE" can never be inside, even when immediately terminating in equipment.
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So how do you transition from USE to interior feeder to subpannel terminal a and b
 
electrofelon said:
Either use USE/RHH, XHHW, or transition in a box on the outside. You need to disconnect for a structure anyway so you could use that as the transition point.
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You mention that I need a disconnect for the building/structure anyway and to use a junction box outside for this but I am confused whether the inside sub panel main 2 pole breaker satisfies this requirement or is another redundant throw handle disconnect required outside? Thanks
 
Jpflex said:
You mention that I need a disconnect for the building/structure anyway and to use a junction box outside for this but I am confused whether the inside sub panel main 2 pole breaker satisfies this requirement or is another redundant throw handle disconnect required outside? Thanks
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225.32 requires the disconnect to be either outside or inside nearest the point of entry of the conductors. Your install appears to meet that requirement. IF you were using USE (only) then you could elect to terminate at an outside disconnect (Line side) and use an approved conductor to an interior panel (load side) or located the panel outside..
 
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