Electric to shed

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  #1  
Old 08-23-12, 06:38 AM
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Electric to shed

I realize there are probably 1000 posts on this subject already but wanted to get some personalized opinions.

Basically here is the plan: This is about 100' run

Run 10/2 off a 20A GFCI breaker at the main panel of the house.
Run this 12" deep in pvc conduit
Comes into a kill switch in the shed where it comes out as 12/2 for the recepticals and single light fixture

Power needs:
1 5000BTU Window AC unit (4.8 A, 115V)
2 Computer Monitors (1 A x 2 )
3 Desktop Computers (1.5 A x 3 )
1 Light fixture (2 32W fluorescent light bulbs)

Opinions?
I need to take two things into consideration:
1st. - Price (I have a rather low budget for the project)
2nd. - Knowledge (My first time doing an electrical project. I will have a friend that works as an electrician helper coming out to work with me)
 

Last edited by kalrith; 08-23-12 at 06:58 AM.
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  #2  
Old 08-23-12, 07:02 AM
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Karlrith,
Depending on where you live, the rules for underground wiring vary. Stop by your communities city hall and talk to the electrical inspector. In some areas, you can use a "direct bury" wire and not even use conduit. The depth of the bury varies also, so if you want to be "by code", just ask. If you run a # 10 2 w ire with ground, you can use a 30 amp breaker which will more than cover the amp draw you are requiring. With all the computers you are planning to use, I would also recommend a good sized battery backup unit with surge protection.
 
  #3  
Old 08-23-12, 07:13 AM
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Yeah looks like code dictates 18" with conduit, 24" if direct buried...

I thought I read somewhere that for residential I can't use a 30 amp breaker..
 
  #4  
Old 08-23-12, 07:19 AM
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You could run a 30 amp feeder to the building but you would need to install a breaker panel at the building. General purpose circuits are limited to 20 amps.

You would be better off to run a 10-3 feeder than a 10-2. You would be able to run more or have expansion room for later.
 
  #5  
Old 08-23-12, 07:26 AM
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You did not mention if your shed is a metal building, but if it is, make certain to attach a good ground to the building itself. The last thing you want is for a metal building to get "hot".
 
  #6  
Old 08-23-12, 08:14 AM
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If feeder is 20 amps or less and GFCI protected, 12" burial depth is fine.

However, I am with PCboss and suggest running a 10/3 cable, using 30 amp breaker, and adding a small panel. This will more than double your wattage available. That would need to be buried 18" minimum.

A small panel can be had for about $30 or less.
 
  #7  
Old 08-23-12, 08:36 AM
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So I could run a 10/3 cable off a 30 amp breaker out to a sub panel in the shed. From the sub panel i could have 2 20A circuits, correct?

Would this require a ground rod? For what I am going to be running would it be required? The cable itself certainly jacks the price up...
 
  #8  
Old 08-23-12, 08:37 AM
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Or if no 240 loads anticipated run 10-3 on a 240 volt 20 amp breaker and wire as a 120 volt multi-wire circuit. That would provide two 20 amp 120 volt circuits with no panel needed, just a disconnect. At some later time it could be converted to a 30 amp 120/240 circuit with subpanel if extra power was ever needed.
 
  #9  
Old 08-23-12, 08:47 AM
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This sounds promising, could i get away with 12-3? Roughly 100$ cheaper
 
  #10  
Old 08-23-12, 09:31 AM
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This sounds promising, could i get away with 12-3? Roughly 100$ cheaper
Yes. You will cut your voltage drop in half if you balance your loads to both legs which will keep it below 3%. You could also then use a two pole switch or A/C disconnect instead of a small panel. Bad side is you would need a two pole GFCI breaker (about $100) That or dig 6" deeper (from 12" to 18").
 

Last edited by Tolyn Ironhand; 08-23-12 at 12:09 PM.
  #11  
Old 08-23-12, 01:31 PM
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If I dug deeper (18") then I could just use GFCI recepticals, correct?

So I could run 12/3 18" underground from a 240V 20A breaker from the house to a two pole switch in the shed and turn it into 2 120V 20A circuits coming out of switch? That sound right?

Thank you everyone for your help!
 
  #12  
Old 08-23-12, 01:38 PM
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12/3-G Type UF cable .
 
  #13  
Old 08-23-12, 02:05 PM
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So I could run 12/3 18" underground
No, 24" for cable or 18" for conduit with THWN. Price out the cost both ways. Even with the added cost of (PVC) conduit that might be the cheaper way depending on local prices
 
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