Wiring a shed to existing a/c power shut off box

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Old 02-24-19, 03:18 PM
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Wiring a shed to existing a/c power shut off box

I need some advice on wiring a shed up to an a/c power box on the side of my house. The box has never been used and is wired with 8/3 wire to a 40amp breaker. Besides most likely not being to code, could I simply wire into the box 8/3 uf-b wire through some 1-1/4" grey conduit about 10 to 12 into the ground and then 100ft away into my shed where I have an 100amp main panel inside? Right now I have and extension cord ran and I'm running on 110v to the panel. I'm wanting the 40amp 220v power to really give my box and all lights and receptacles power so I can run more then one power tool or a few lights, power tool and a radio without popping a 20amp breaker in my house. Oh and by the way I barely know enough to get me by. Lol
 

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Old 02-24-19, 04:08 PM
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Minimum burial depth for conduit is 18 inches. Individual conductors such as THWN will be easier to pull than cable. Ground can be #10 copper. You will be running 120/240 not 220.

You will need one or two ground rods at the shed. They can be connected using #6 copper. The subpanel will need a bonded ground bar which usually has to be bought separately. Neutral busses must be isolated.
 
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Old 02-24-19, 04:17 PM
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wired with 8/3 wire to a 40amp breaker
8/3 would be 2 hot conductors (black and red), and neutral (white) and a ground. Do you have all these wires? I ask because normally an A/C does not need a neutral.
 
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Old 02-24-19, 04:19 PM
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If you decide to go with UF direct buried it will need 24" of cover.
 
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Old 02-24-19, 08:48 PM
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Read through this thread for a basic understanding of your project.

https://www.doityourself.com/forum/electrical-ac-dc/495452-sub-panel-diagrams.html
 
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Old 02-25-19, 02:19 AM
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Last edited by ray2047; 02-25-19 at 02:58 AM. Reason: Add image and reduce size.
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Old 02-25-19, 02:55 AM
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A/C box

The a/c box has 4 wires a red going to one spot in the box and a black going to another spot, the bare copper wire is screwed to the box itself but the white wire is capped off with a wire nut. All four wires are running to the main house breaker box. I turned off a 40amp double pole breaker label a/c then it kills the power to the outside box in question. What does that tell you? Just trying to figure out how to supply at least 30amps from that 40amp a/c box to the shed/man cave 75ft away that was wired like a mini house, instead of the 15amp, 100ft orange extension cord running on top along the ground for the past year. I'm tired of tripping a power strip when using more equipment at once. Besides electic code regulations and possibly digging into or cutting the wire because it's not buried. What would be the problem burying it 10 or 12" deep? I'm going to load some pictures as soon as I figure iout
 
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Old 02-25-19, 03:00 AM
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You have all the wires you need at the disconnect. As you stated in your original post you can supply 40 amps using #8 for H-H-N and #10 for ground. In your situation minimum burial depth is 18" with conduit or 24" using direct burial cable. Does the panel in the shed have a main breaker? Plaease post a picture of that panel with the cover off. How to Insert pictures

Please note your effort to use DropBox failed. Better to attach your image on your computer to your post once you have cropped it and reduced the width to 800 px
How to Insert pictures
 
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Old 02-25-19, 08:08 AM
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The problem with 10" to 12" deep is it violates electrical code. Unless you put the wire in rigid metal conduit or cover it with 2" of concrete, then the cover can be 6".
 
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