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Dr. Fix-It
Dr. Fix-It, Handyman
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What is best way to run power to a tool shed undergound about

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What is best way to run power to a tool shed undergound about 50 feet from the main panel? A 20 amp circuit for lights, a couple of outlets and small very small window AC is all I need.

Hi my name is XXXXX XXXXX Dr.Fix-It, Your online expert ready to assist you..

I would suggest for a 20amp circuit to run 12awg thhn stranded wire from a 20amp breaker to the tool shed in your buried 3/4" pvc piping. May install a 20a disconnect box in the shed to feed the outlets and can also use GFI outlets for added electrical protection.


Hope that helps and let me know if have any other concerns...


~ Please give it a try and let me know if have any questions along the way with a reply....only rate my answer ok, great, or EXCELLENT after we have worked on the issue together to your satisfaction. Bonuses are welcomed & appreciated. I look forward to any future inquires as well, Thank You ~

Customer: replied 4 years ago.



Your answer is very helpful. So I won't need the THWN because it is in conduit? Since the shed is not subject to inspection I won't wire it til after home inspection anyway, but is there any reason I should worry about having run the conduit near the water line? Ten inch depth is OK? Of course, it will have GFCI protection as you suggest.


What kind of disconnect would I use? In the wall inside? The conduit run up inside where the studs will be. Don't think I have seen one of those that is not a service panel. Any suggestions appreciated. Thanks very much for your help!

Hey John glad to help, I would just mount a fuse box in the shed to have a means to cut out the power on that end if needed without having to go to the main panel... I have used these ac boxes and installed 20amp fuses in them > Pipe in to the box mounted on surface or can be inset as well, then pipe out to the outlet boxes and run the same stranded wire throughout.


As long as you know where the pipes are run and are sealed properly, then do not have to worry about water getting in or accidentally hitting the pipe when digging in the area.

Customer: replied 4 years ago.

Fantastic! Thanks for the link! So really it is same as the disconnects I use for HVAC etc.? One last idea. In the 3/4" conduit could I use #10 wire just in case with a 30 amp breaker? Just realized some of my power tools may have surge amps a little higher than I realized. Thanks again for all your help. You're the greatest!

Yes can use the HVAC type box as are cheap... If want to go to 30amp, then would use 10awg stranded (makes wire more flexible and durable), get three spools > black for the hot 120 vac, white for the neutral and green for the ground.
Customer: replied 4 years ago.

Thanks for reminding me about the wire color. Also, I was just reading your answer again. Can I use disconnect with no fuse since it is on breaker? Also, once in the shed I will have sheetrock on the walls so I can just go to Romex? Thanks again, as you have really been helpful and I will call on you again if you don't mind.

John you can just have the main 20a breaker run to junction box in the shed, then would have to turn off and reset from the main, the disconnect helps localize and isolate the shed feed, so do not have to keep going out the main. If will sheet rock the shed, then yes can run romex along the studs without piping the individual wires.


I am here to help and can follow up on this even after giving rating... Bonuses are welcomed & appreciated.


Remember Dr.Fix-It on any future inquires as well > <


Dr. Fix-It and other Home Improvement Specialists are ready to help you

Hey John just looking over your inquiry and wanted to clarify that the THHN wire is also rated for THWN application... The THHN electrical wire is dual rated with THWN wire because they're manufactured very similar to each other with almost no cost difference... THHN stands for "Thermoplastic High Heat Resistant Nylon Coated" and also have the THWN rating on all of the THHN electrical wire. The added "W" stands for water resistant. Per the spec of the wired reels referenced above >


Well hope get the house and shed together... Let me know how it goes, Shaw

Customer: replied 4 years ago.

Thanks a million for the help and the clarification on the wire type. I appreciate you, Shaw,