Gauge wire and type needed for detached building

[Corbin5754]

Hey guys I'm wanting to run power from my 100 amp house box to my steel building in the backyard with a 100 amp sub panel box. and I want to run wiring underground and it's about 70 feet away. Can you tell me what size wire and type needed to do this.

 

[pattenp]

How many amps do you want to feed the 100A subpanel with. I question if you need a full 100A at your building.

 

[Corbin5754]

Really all I want is 3 outlets ea on a 20 amp breaker

 

[CNGsaves]

The "quasi-standard" setup that works for lot of detached garages for guys on GJ is to do:
. . . 1) 2" buried plastic electrical conduit w/ sweeping 90 degree elbows
. . . 2) MHF (mobile home feeder) aluminum 2-2-2-4 (only about $1.50/ft)
. . . 3) Distance less than 100 ft, install 90A breaker in the house to feed subpanel
. . . 4) 2 ground rods at the detached garage (ie subpanel)
. . . 5) Separate ground bar in Subpanel that is NOT bonded to Neutral
. . . 6) Entire run of MHF in conduit as indoors it MUST also be in conduit

 

[theoldwizard1]

The "quasi-standard" setup that works for lot of detached garages for guys on GJ is to do:
. . . 1) 2" buried plastic electrical conduit w/ sweeping 90 degree elbows
. . . 2) MHF (mobile home feeder) aluminum 2-2-2-4 (only about $1.50/ft)
. . . 3) Distance less than 100 ft, install 90A breaker in the house to feed subpanel
. . . 4) 2 ground rods at the detached garage (ie subpanel)
. . . 5) Separate ground bar in Subpanel that is NOT bonded to Neutral
. . . 6) Entire run of MHF in conduit as indoors it MUST also be in conduit

I would go with a 60A breaker in the house pane; Use Schedule 80 sweeps. (String trimmers will break Schedule 40.)

MHF is rated direct bury, but it must be inside conduit when in a building. You can use AL SER (same size) without conduit inside of a building.

 

[ard]

Good advice above.

OP, keep in mind that if you have a 100A service on the house, drawing 100A, or even 90A in the shop will likely result in tripping the main...BUT... Someday you or someone else may upgrade to a 200A on the house- so it would be nice to have a decent service wired.

If you run the 2" with the 2224 (capable of 90A) but put in a 60A breaker you will be in good shape now, and in the future.

Alternatively, still go with 2" PVC, but wire it with the wire you need for whatever smaller service you want now. Someone can always pull larger. The cost of 70ft of 2 inch conduit versus 1in conduit is a few lunches.

Oh, also toss in a piece of 3/4 for low voltage stuff you might need, Internet, alarm, whatever. I can't stand the sight of an open trench without spare conduits....

 

[Corbin5754]

Thanks for the ideas guys

 

[wyliesdiesels]

it would be really hard for a typical solo person to pull 60a let alone 90a....