Supply electricity to a shed from breaker box


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Old 05-26-14, 10:48 PM
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Supply electricity to a shed from breaker box

I live in Southern California. I just finished framing a 8x12 shed in the back yard. After much debate, I have decided I will supply it with electricity. I was hoping the forum could provide me opinions on how to complete my task.

I have a new 200amp breaker box on at the back of the house. The shed is approx 100' away from the breaker box, it is however a straight North/South line from breaker box to shed.

I figure I will need to dig a trench, lay tube, run cable through the tube. I prefer this to the direct underground cable I have seen.

Okay... so... what do I need to do from there?

I want:
1) A new and separate breaker solely for the shed
2) A sensor light outside the shed
3) A switch for a light bulb inside the shed
4) An electrical outlet inside the shed
5) An electrical outlet outside the shed

Major questions I have in my head
1) What kind of wire will I need? A Home Depot employee said I need a heavier cable because I will have voltage drop. If I remember correct, he said I would need three separate wires and run them through the tubing.
2) I think I need some kind of box device at the shed, so I can shut power off at the shed and not at the 200amp breaker box? Is that the main purpose of this device... again a friend recommended it but I forget the logic for doing so.
3) How do I put a new breaker in?

I'm a newbie, but I think this should be an easy process, except for digging a 100' trench 18" deep for the tubing.
 
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Old 05-26-14, 11:23 PM
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lay tube, run cable through the tube. I prefer this to the direct underground cable I have seen.
If you prefer conduit best practice is to use individual conductors such as THWN. Cable is hard to pull and not needed.
What kind of wire will I need? A Home Depot employee said I need a heavier cable because I will have voltage drop. If I remember correct, he said I would need three separate wires and run them through the tubing.
Cable is not separate wires. Cable is two or more conductors in a metallic or non metallic sheath. He is correct about using individual conductors. Wrong about voltage drop. Maybe heavy motor loads at more than a 100 feet. Bur normal loads at a 100 feet not a problem.

Depending on the loads if they are no more than a few lights an occasional hand tool but no A/C or electric heat or welders or air compressors a single 120v 20 amp feed should be enough. You would need one #12 black, one #12 white and one #12 green THWN wires in ½" PVC conduit. (I'd go with ¾" conduit to future proof it.)

You would install a 20 amp single pole beaker in your breaker panel. You would use a breaker rated for your panel. They just snap in.

At the shed you would install a 20 amp SPST switch (heavy duty light switch) as your disconnect in a single gang box. From there one cable to your light switch and one cable to your first receptacle. First receptacle must be GFCI and all other receptacles non GFCI receptacles connected to the load side of the GFCI. All cable (NM-b) used in the shed must be #12.
 
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Old 05-27-14, 12:09 AM
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What is a "motor load"? Just curious. I may (twice a year) run a circular saw outside the shed. If it means another $100 in wires, I'll just drag the saw to the house. For the most part, the electricity at the shed will be for two light bulbs, string lights (bigger than Christmas bulbs), and a radio/speakers.

I was thinking inside the shed I'll have a two gang box. One switch for inside light and other switch for outside light with sensor.

From the 20 amp SPST switch I'll have...
a) cable go to two gang box
b) cable go to GFCI receptacle
c) then cable from GFCI receptacle to next other receptacle

Should I make the exterior receptacle the GFCI? Or, it doesn't really matter? My siding is T1-11, that's all.

Also, this 20 amp SPST switch doesn't sound like what was recommended. Could there by any other alternatives, or, nah that's the one.

Final question and not sure how to describe it. For the outside light bulb with a sensor, I want what I have with my house flood light. It has two switches. One switch permanently turns on my flood light (no sensor, it is just straight on). The second switch activates the flood light's motion sensor (and if something moves, then the flood light turns on - and then off if there's no more motion). I like having this option. Is this difficult to wire? Is there a name for this type of wiring configuration?
 
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Old 05-27-14, 01:08 AM
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What is a "motor load"?
It mostly the extra amps needed to start a large motor. The circuit described will be fine for a circular saw.
Should I make the exterior receptacle the GFCI?
So long as the first receptacle is a GFCI and all others are non GFCI fed from the load side it doesn't matter which is first.
Also, this 20 amp SPST switch doesn't sound like what was recommended. Could there by any other alternatives, or, nah that's the one.
The switch I suggested is best choice for this. You could use an unfused air conditioner disconnect but that is way overkill for this.
It has two switches. One switch permanently turns on my flood light (no sensor, it is just straight on). The second switch activates the flood light's motion sensor (and if something moves, then the flood light turns on - and then off if there's no more motion). I like having this option. Is this difficult to wire?
Possible but would need to know more about the exact wiring. Sounds somewhat creatively engineered. Did it come with the house?
 

Last edited by ray2047; 05-27-14 at 08:57 AM.
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Old 05-27-14, 06:41 AM
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The light switch for the current flood light has a double rocker for it. I had the electrician install it when we moved into the house, along with other electrical work.

I just remember my dad had this for his flood light in his backyard, I wanted it for mine, and now I want it for the light outside the shed.

When I described it to the electrician, I swear he had some kind of knickname for it, like "jack rabbit" or something.

As I said the double rocker switches (lets call them A and B?) ...
A. permanently turn on the flood light (it doesn't care for motion, the flood light just turns on and stays on until switch A is turned off)
B. The flood light is on, but only the motion sensor ability of it (if motion trips the light then the light turns on until an amount of time has elapsed)

I think most people's flood lights has the B option only. I may be content witch just the A option.

Thanks for the replies Ray. Any chance I can goof this and burn the house down?
 
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Old 05-27-14, 07:09 AM
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If the ,light was wired off the travelers of a 3 way switch it would give you this option if a change is made after the sensor.
 
 

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