What's up guys I am going to put an outlet outside at my summer house this weekend. I am going to add a 20 amp breaker to my panel and run 12/2 outside. The wall I need to go through is cement/foundation. What size drill bit would I need to run 12/2 through the concrete wall to the exterior of the house? I will mount a gfi weather proof box over the hole and caulk.

The house is 2 hours from any hardware store and want to make sure I have the right stuff to bring up. Thanks.

 

12/2 NMB will fit through a 1/2" hole but 5/8 will give you a little wiggle room. If the box will be mounted right over the cable exit hole you can use NMB.

However, you will need a clamp where the cable enters the box. If you mount a standard romex clamp to the outside of the box, you will need a bigger hole to allow for the clamp. Probably at least an inch. You don't need to drill the larger hole all the way through, just deep enough for the clamp. Or, if you use an external box with the threaded holes, you can often mount the clamp inside the box. I would test fit it before you go. Make sure there is room for the GFCI in front of the clamp if you go that route.

Put a nice bead of caulk behind the box to keep water out of the hole, and then a smaller bead all around the box once it's mounted.

Code calls for an in-use cover on most external outlets now, so you will need one of those as well.

 

You could use the 1/2" bit all the way through the wall. From the outside use the same bit to drill partial depth holes around the initial hole to clear the clamp.

 

AIR, cable passing through a masonry wall needs to be sleeved.

 

^ I don't believe that's correct. You can bore a hole through concrete and pass the wire through. Nm cannot be embedded in concrete ( poured wet concrete and embedded without a sleeve.

Unless this has recently changed

 

I have seen no changes to this section. Sleeved if embedded, otherwise no sleeve.

 

Thanks pc for clarifying .

I bought outdoor caulk to put behind the box before mounting it. But I see a lot of guys putting duct seal around the box as well. Would you agree this is a good ideA. Or just use the same caulk I bought and throw a bead around it?

 

Either should work. I would use caulk.

 

Yes, latex caulk is okay but I'd put a bead on the back of the box before fastening. Then wipe off any that squeezed out with a damp sponge. I'd provide a weep at the bottom by not applying caulk there. That way any moisture that got behind wouldn't be trapped