Moved: questions for outdoor electrical box


Old 04-20-16, 02:46 PM
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Question Moved: questions for outdoor electrical box

1. Assuming you are using NMB right into the back of the box, what NMB connector do you use?

2. Is there code for how high outdoor weatherproof boxes need to be off the ground?

3. Is there code for how close you can have two weather proof boxes near each other? I want to install a weatherproof box in the vicinity of another outdoor box that goes to my Generac standby.

Last edited by Khaleesi; 04-20-16 at 05:12 PM.
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Old 04-21-16, 12:04 PM
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4. Do you have to use those waterproof wire nuts?
Old 04-21-16, 12:46 PM
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1. If you are using a surface mount box you can use a standard NMB clamp connector screwed into the tapped hole in the back of the weatherproof box. Put a heavy bead of caulk on the back of the box all around the clamp before you push the box back against the wall to keep water out of the house and the box. After you secure the box to the wall, put a heavy bead of caulk all around the box (except for an inch or two of the bottom edge. This allows any water that somehow gets behind the box to get out.

You may want to consider using this type of box:

They recess into the wall so they don't stick out so far and include the in-use cover. They make singles and doubles and have versions for flat surfaces as well as common siding. You do have to cut a larger hole in the siding.

2. No code minimum. But it's a good idea to keep them above typical snow height if you can, if that's a factor in your area. If you don't use the recessed box and they are too low they get kicked and hit by the lawnmower, etc. If you use the recessed box above it's better if they are at least a foot or two off the ground, otherwise you have to kneel down to be able to see the outlet to plug in a cord.

3. No.

4. No.

Outlet does need to be a GFCI (or protected by another upstream GFCI).

You do need a weatherproof "in-use" cover. The old snap covers that only worked when there was no cord plugged in are no longer allowed.
Old 04-21-16, 01:20 PM
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I saw a video of a guy using a black putty around the NMB connector.

I couldn't find the video again.

Does anyone know what that black putty is?
Old 04-21-16, 01:26 PM
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It's called Duct Seal or commonly "Dum Dum". About a dollar for a one pound block of it in the electrical or HVAC section of the hardware. It would be ok to use that or silicone caulk. I prefer silicone caulk because it has a longer lifespan outdoors.

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