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#167507 - 08/14/07 01:00 PM USE In Conduit & Inside Use
InspectorE Offline
Member

Registered: 10/08/04
Posts: 51
Loc: Hudson WI USA
Comments were made last year (August 4, 2006) regarding putting USE cable in conduit & inside use of same. I have that situation, so I'm asking for your input.

The discussion was using USE in conduit for a pool situation. My situation is just a residence with a center pole/meter, so NEC 680 isn't applicable.

Here's the 2002 and 2005 NEC 338 sections of interest:

2002 NEC

338.10 Uses Permitted.
(B) Branch Circuits or Feeders.......
(4) Installation Methods for Branch Circuits and Feeders.......
(b) Exterior Installations..........
Type USE shall be permitted to be terminated in enclosures at an indoor location where Type USE cable emerges from the ground. The length of the cable extending indoors to the first termination box[not defined] shall not exceed 1.8 m (6 ft). Where Type USE cable emerges from the ground at terminations, it shall be protected in accordance with 300.5(D)...

2005 NEC:
(b) Exterior Installations........
Type USE cable installed as underground feeder and branch circuit cable shall comply with Part II of Article 340 [UF cable requirements]. Where Type USE cable emerges from the ground at terminations, it shall be protected in accordance with 300.5(D)....

It appears that the 6 foot restriction inside a structure to connect a USE feeder to a "termination box" has been eliminated, although it is unclear to me if the NEC folks meant to prohibit use inside under any circumstances. It just says that the cable has to be protected & installed in accordance with Section 340.

As far as putting USE in conduit, here's page 40 of the UL listing for USE...

Page 40 UL Wire and Cable Marking Guide
Types USE and USE-2 — Indicates cable for underground installation including direct burial in the earth.

It says "including", not "limited to" direct burial in the earth. I think the use of the word "including" was deliberate and not meant to be the sole use.

Although there isn't a table for USE in conduit, measurement in my instance shows it just meets the percentage fill requirements by a small amount.

All the conductors are insulated and installed in Schedule 40 conduit buried 6' below finish grade.

I think at worst case, I would have to put a "termination box" at the rim joist of the house to make the transition from USE to inside rated wire for the short run to the breaker panel.

Again, I don't see that the 2005 NEC prohibits short inside runs of USE to the "termination box", it has simply removed the 6 foot specification.

I wish the NEC folks would simply prohibit something if that's what they want. You almost need a Philadelphia lawyer to try and figure out some of these sections. Perhaps the 2008 NEC will simply prohibit USE inside under any circumstances.

Thanks guys!

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#167513 - 08/14/07 03:32 PM Re: USE In Conduit & Inside Use [Re: InspectorE]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
When you read the commentary in the 2005 ROP (7-191 and the next couple) it is clear the intent of removing the 6 foot language is intending to eliminate any USE in the house.
_________________________
Greg Fretwell

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#167630 - 08/16/07 03:39 PM Re: USE In Conduit & Inside Use [Re: gfretwell]
Mark20 Offline
Member

Registered: 03/17/07
Posts: 25
Loc: Maryland
get an nec handbook and read the green shaded section under article 338.1

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#167640 - 08/16/07 05:34 PM Re: USE In Conduit & Inside Use [Re: Mark20]
InspectorE Offline
Member

Registered: 10/08/04
Posts: 51
Loc: Hudson WI USA
Southwire has multiple rated service cable to eliminate the issue...here's the address:

http://www.southwire.com/processGetArticle.do?commonId=17deae6fef122010VgnVCM1000002702a8c0____

I'm sure there are others...

Again, thanks!

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#167675 - 08/17/07 02:04 PM Re: USE In Conduit & Inside Use [Re: InspectorE]
kale Offline
Member

Registered: 11/08/02
Posts: 168
What is the problem with using USE indoors?

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#167696 - 08/17/07 06:50 PM Re: USE In Conduit & Inside Use [Re: kale]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
It burns
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Greg Fretwell

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