How to install an outdoor receptacle on the other side of this indoor receptacle?

Question

I want to have access to electric on a porch, and there's an indoor receptacle right around where it would be helpful to have an outdoor one. I did some research and it seemed simple enough:

1. Open the indoor receptacle up to access its gang box, look for a clear path behind it, knock out another corner hole and use a long bit to drill through it and through the wall outside.

2. The outdoor hole is where the wire will come out, so use that to place the outdoor gang box as a template, mark it on the outdoor wall, then cut through the siding and wall with a jigsaw

3. Run a new jumper NM cable through the indoor hole, run it through a gang box to be installed outdoors and install that. Hook the wire up on both ends, finish up outdoor receptacle, then it's all set.

When I started that first step, I found how this DIY project is not so simple (of course). I'm looking for expert input on how my above steps need to adjust to make this work. Here are some photos of what I'm working with, followed by a description.

What I found is a metal, new-work gang box that had side straps to the stud where the door is framed out. Peaking around and behind that box, I see that when facing the interior gang box, there is NM cable vertically along both the left and right edges of the box, but cable only enters from the right corners (bottom and top, both wired to the receptacle). Looks like fiberglass insulation behind that.

The wall is too narrow for gang boxes to be back to back, and there are these vertical cables to navigate. It's hard to imagine any possibility other than those other cables going to soffit lights and a ceiling fan on the same circuit, since this is an addition with a concrete foundation and one circuit for this side of the room.

So, here's what I'm unsure about:

• How should I go about drilling a hole and running a jumper cable to a new outdoor receptacle? Just find a spot that looks clear behind the metal gang box, take a drill bit for metal and drill a fresh hole through the indoor gang box?

• How to cut out the outdoor part (siding, wall) without damaging cables in the wall? I had planned to use a jigsaw but have an oscillating saw which might be better to very delicately cut only as deep as needed and where I can see what I'm cutting.

• Where to locate the new box and what type to use? I figure it is best to attach to the stud, so I should aim to install the new box oriented vertically(?) and above or below the old one. I'd drill a hole in the old box at an angle and height accordingly, to try and pass cable to the new box either directly above or below the old, though that does put me in line with those up-down cable runs. The only boxes I'm aware of that let me attach to the stud without opening a wider hole are smart boxes, or I could mimic those by making my own pilot holes and screw through any box into the stud at an angle.

Answer 1

So first you have to decide, “do I want my receptacle flush or do I want a surface mount receptacle.”

If it’s external it’s gonna be super easy, all you’ll need is…

• 1 Bell Box 1/2”
• 1 Weatherproof Cover
• 1 WP GFCI outlet
• 1 Two Screw Romex Connector 1/2”
• 1 RC 50
• Romex
• Screws
• Silicone

You’re going to drill a pilot hole through the back of the metal box. Then take a hole saw bit that just fits over the Two Screw Connector and Cut a hole in the siding. Then from that side knock out the metal KO in the back of the indoor metal box and put an RC 50 in the hole. After that run 12/2 Romex through the hole. Tighten the Two Screw Connector around the Romex and shove it back. Secure the Bell Box to the wall with the kit (or bust some holes in the back of it). Make up your Outlet and put the cover on. Then go inside and wire nut all of your hots, grounds, and neutrals together with a pigtail out of each. Hook up your outlet and put it back together. Go outside and silicone the Bell Box.

The second option is a flush receptacle recessed back into the wall. This is the option I would do for my house, but it could be a bit more difficult.

-1 Side Screw Or Winged Cut-in Box

-WP Cover

-12/2 Romex

-1 WP GFCI outlet

From what I can tell in the picture this should work well with your studs. You’ll start by checking what side of the metal box your stud is on (I think the right side is open, which is good). You’ll use a fin tool to cut in a hole the size of an outlet box in your siding (I recommend putting the WP cover up to it to get an idea of where it will lay flat, don’t mess up lol). Go inside to your metal box and knock out either one of those metal ko’s. Put an RC50 in whichever one you knock out and run Romex through it, aiming for the hole you cut in the siding. After you can pull it out of the hole you need to run it into the back of the cut-in. Put the cut-in in the wall, and make up your WP GFCI. Go back inside and wire nut the wires in the metal box again leaving pigtails (no backstabbing). And make up that outlet. After that you can put the WP cover on outside, make sure that it’s flush against your siding. You might need to do some trimming. After that just test make sure everything works.

No need to put the WP GFCI inside, I assume the other commenters went wrong because they didn’t use WEATHERPROOF GFCI’s. I’ve put up many and never had a single issue with any of them. It will be a tight fit inside your gang able box. If you do however decide to put it inside, please tape around the GFCI so that it doesn’t contact any of the metal inside. Also if you already have a GFCI/AFCI breaker don’t worry about a GFCI outlet, just get a regular WP outlet.

Best of luck to you, if you don’t have a lot of experience with electrical make sure to turn off the breaker. If you have any questions or need any clarification I’ll try and check this post again later.

Answer 2

IMO you don't need to do any drywall work that one of the comments in your OP suggests. Your existing metal box is likely attached to a stud—odds on its left side. Since the outlet is so close to the door, you can easily determine where the box is from the outside. With siding, I like flush outlets as opposed to surface mount, so I'd cut a rectangular hole for the outlet on the outside, a few inches above the existing box. Start your hole as close to the stud as practical, and take care to avoid cutting the existing cable. (I like an oscillating multitool for cutting the hole.)

Once you've got a hole, you should easily be able to access the cable holes for the existing box (from the outside of the box) to be able to add a short run from there to your new box. May need to do a little siding R&R to get the new siding box's flanges under the siding.

There are many siding boxes out there, but I like this one (used successfully before), because it includes pretty much everything in one kit: https://www.hubbell.com/taymac/en/products/p/2294585 (I get them from Amazon)