As the title states...looking to run a 100A service from my 200A panel. Length is appx 140ft. Planned to use 1/0 Aluminum URD however thats not going to connect to the breaker. Do I bug on #2 copper after I transition thru the LB or is there a small box that has lugs similar to service feed where I can transition inside for same purpose? Thx much!
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100a Sub Panel Service Feed
- Thread starter 64duece
- Start date
pattenp
Well-known member
For 100A @ 140ft you can use #1 Al. Also you need to transition to a different type wire for the inside, the URD has to be terminated on the outside. If you can get by with a 90A feed then use 2-2-2-4 (MHF) Mobile Home feeder. The MHF can be installed inside, but does need to be in conduit.
Thanks for the tip. I have a Tig machine on a 50A breaker and if I'm doing aluminum it'll use it. We have a compressor and lifts..mostly worried about in-rush current if I'm welding and a buddy is using an air tool or lift. Ill spend a few extra bucks for the few additional Amps of headroom. What do you recommend for making the outside transition? I planned to use LBs on both house and shop.
Charles (in GA)
Well-known member
As pattenp mentioned, URD cannot be used anywhere inside a building, unless it has other markings on it that do allow its use inside (which is doubtful with URD). The URD does not have the fire resistance required for inside use.
Charles
Charles
pattenp
Well-known member
To switch to something like SER for the inside you will need to use a large junction box outside for the splice. A PVC box that's 8X8X4 should work. A LB body will not have the needed volume for doing a splice.
theoldwizard1
Well-known member
For 100A @ 140ft you can use #1 Al. Also you need to transition to a different type wire for the inside, the URD has to be terminated on the outside. If you can get by with a 90A feed then use 2-2-2-4 (MHF) Mobile Home feeder. The MHF can be installed inside, but does need to be in conduit.
Another endorsement for MHF. To clarify, MHF does NOT require a conduit when buried. Conduit is only required inside. If your conduit goes into the ground next to a building, use Schedule 80 pipe. A good string trimmer will breaker Schedule 40 (standard) pipe.
matt151617
Well-known member
Out of curiosity, is a crawlspace under the house considered "inside"?
Yes- if it penetrates through the outer wall/foundation, then it's inside.