Power Feed to SHED


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Old 06-26-13, 01:14 PM
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Post Power Feed to SHED

I am planning to run a 120 volt A/C power feed to my shed; it will be used to power a couple of 20 amp outlets (for battery charges, tools, etc) and two florescent shop lights and an outside security light. I plan to run this underground, around 75 feet from the house basement (brick wall). I will be using a UF rated cable (# 12, 2/c with ground). I will be using a 20 amp GFI/C.B installed in the main panel of the house for this circuit. I have obtained a permit for this work and had a brief talk with the city Inspector; according to him I need to trench this cable 12 inch deep from the house to the shed. My questions are:

1. I have an embedded conduit (¾ inch PVC) installed in the slab for the shed, is it OK to use this to bring the cable into the shed or do I need to install a box or an L.B on the outside of the shed wall?
2. I have a concrete pathway (3ft about 3 inch thick ) in the way of the cable route, do I need to go the full 12 inch under the concrete or can it be less?
3. Do I need a disconnect switch inside the shed for the incoming power and if I do, would a regular 20 amp switch be OK?
4. Can I use the UF underground cable all the way to the main panel and the GFI or do I need to transition it in a pull box / junction box inside the house ( and in the shed ) to a standard # 12 indoor cable?
5. Is ½ inch conduit, ½ L.B size O.K for this work?
 
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Old 06-26-13, 01:40 PM
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Welcome to the forums!

The 12" depth is OK since you're installing a GFCI circuit breaker in your main panel.

You can run the Type UF all the way.

You can come up to 8" below the ground surface as you go under the walk.

Coming into the shed through the existing conduit should be OK.

1/2" pipe will be a bit of a fight to get the cable through but should work.
 
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Old 06-26-13, 01:49 PM
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1. I have an embedded conduit (¾ inch PVC) installed in the slab for the shed, is it OK to use this to bring the cable into the shed or do I need to install a box or an L.B on the outside of the shed wall?
You may come straight in.

I have a concrete pathway (3ft about 3 inch thick ) in the way of the cable route, do I need to go the full 12 inch under the concrete or can it be less?
You can use a piece of pipe on the end of a garden hose to tunnel under the sidewalk.

Do I need a disconnect switch inside the shed for the incoming power and if I do, would a regular 20 amp switch be OK?
Yes; yes.

Can I use the UF underground cable all the way to the main panel and the GFI
Yes but if it is more than a few feet I'd transition to NM.

Is ½ inch conduit, ½ L.B size O.K for this work?
Best practice is not to use conduit if you use cable except for short sections to protect it where it enters and leaves the ground. If you want to use continuous conduit use individual THWN wires and transition to NM at the house.
 
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Old 06-26-13, 01:50 PM
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Welcome to the forums! Others will chime in, but I'll get it started.

UF cable normally has to be buried 24". Conduit 18", but if your inspector is fine with 12", so let it be done.
1) Running the UF into the conduit elbow up into the shed is fine. It adds to the protection needed as it reaches the surface.
2) I would obtain a piece of 7/8" rebar, dig two holes at the entrance and exit of the place under the sidewalk and force the rebar under the concrete at the prescribed depth, since it is a minimum under concrete anyway.
3) You can probably run the cable into a junction box as it enters the building via your conduit and branch from there to you receptacles and lighting. Only two wires would be needed, so I see no real need for a disconnect.
4) You can use the UF from panel to jbox in shed
5) Running non metallic cable has its drawbacks, and the smaller the conduit/lb size the more difficult it is to run. I know you only have a small run from the ground to the entrance to the panel, but I would graduate to 3/4", purely from an aggravation standpoint.

edit. I was considering this a shed, and not a garage when mentioning about the disconnect. Not sure if it is required or not. Ray types faster than me and he suggests it. May want to check with your inspector on that, too.
 
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Old 06-26-13, 02:26 PM
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Best practice is not to use conduit if you use cable except for short sections to protect it where it enters and leaves the ground. If you want to use continuous conduit use individual THWN wires and transition to NM at the house.
If I understand the plan correctly, it's direct burial with GFCI protection. The conduit is a piece already in place for bringing it into the shed.
 
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Old 06-26-13, 02:59 PM
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I read
Is ½ inch conduit, ½ L.B size O.K for this work?
to mean continuous conduct. Max, which is it?
 
 

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