Using service entrance cable indoors

Reply

  #1  
Old 10-26-09, 06:19 PM
T
Member
Thread Starter
Join Date: Oct 2009
Location: Michigan
Posts: 11
Received 0 Votes on 0 Posts
Using service entrance cable indoors

Hi,
Is type USE service entrance cable allowed to run across joists from one end of a basement to the other before going outside and underground to feed a sub-panel in an outbuilding? After searching an old NEC book for the answer I believe the answer is "no". But I do believe it can be done with type SE. I'm thinking it would be OK to run type SE across the basement to a junction box, then join to the type USE just before going out through the wall and down into the ground through conduit. Would this be acceptable? It sounds easier and cheaper than the "THHN in conduit" route. Also, if this method is acceptable, what is the recommended way to splice the aluminum SE to the aluminum USE cable? Your input would be appreciated.
Thanks,
Tavor
 
Sponsored Links
  #2  
Old 10-27-09, 05:48 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,142
Received 83 Votes on 71 Posts
You are correct the USE cannot be used indoors.

SE is service entrance cable. It would not be used to feed a subpanel in the garage. You should use SER cable with 4 conductors.

FWIW, the cost of either Polaris connectors or split bolts and tape, it is probably less expensive to run the conduit and THWN conductors. It would also remove the splice in the system.
 
  #3  
Old 10-27-09, 10:52 AM
T
Member
Thread Starter
Join Date: Oct 2009
Location: Michigan
Posts: 11
Received 0 Votes on 0 Posts
Thanks for the response pcboss. It leads to a follow-up question though. When you say using conduit eliminates a splice do you mean I should run the conduit and THWN all the way to the barn? I failed to mention that the total distance from the main panel to the barn is 300 feet (50' in the house + 250' to the barn). Judging by the prices I've seen so far the aluminum USE cable is WAY cheaper than THWN. Does the 300 foot distance tilt the choice in favor of the cheaper cable?
 
  #4  
Old 10-27-09, 11:08 AM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 43 Votes on 41 Posts
Originally Posted by tavor View Post
When you say using conduit eliminates a splice do you mean I should run the conduit and THWN all the way to the barn?
That is a possibility.

Judging by the prices I've seen so far the aluminum USE cable is WAY cheaper than THWN. Does the 300 foot distance tilt the choice in favor of the cheaper cable?
You were probably comparing copper THWN vs. Aluminum USE, which explains the huge difference in price -- there are individual conductor aluminum wires which will be closer to the USE price. However for a 250' underground run, direct burial aluminum cable is certainly going to be the cheapest. The run through the house can be done either with conductors in conduit or SER cable (should be about the same $/ft as USE).

The splice box should be on the outside wall. You didn't say what size cable, but you will need a good sized box. You can use Polaris connectors for the easiest splice, but they are expensive. Use split bolts and heavy tape for a more economical splice. In either case you'll want to use plenty of no-ox grease on the aluminum splices, and buy connectors that are rated for the size and type of metal you are splicing.
 
  #5  
Old 10-27-09, 03:35 PM
T
Member
Thread Starter
Join Date: Oct 2009
Location: Michigan
Posts: 11
Received 0 Votes on 0 Posts
OK, got it; the splice box goes outside the house. Thank you, I really appreciate the help. Oh, and yes, I was indeed comparing copper THHN/THWN to aluminum USE. Not a fair comparison really. But I don't think I have ever seen aluminum THWN, or I didn't recognize it as such.
Thanks again,
Tavor
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: