I plan to install electrical outlet in the following location:

enter image description here

It would be used mostly for:

  1. USB camera that is always plugged in.
  2. pressure washer.
  3. car charging.

I plan to splice the wires from the electrical box behind the lamp which I pretty much always leave powered on because it has a built in motion detection sensor:

enter image description here

I watched few youtube videos on how similar projects are done and If I understand correctly, I have to:

  1. Turn off electricity at breaker box.
  2. Buy old-work electrical box (i.e. one that has those wings and can be attached to the wall opposed to stud). PVC material should be preferred as then I don't have to use metal-sheathed cable.
  3. I need to drill a hole in the wall where the new electrical box will be installed and then use a sawzall (or something similar) to cut out rectangular shape that matches the electrical box.
  4. Punch a hole in the bottom of electrical box behind the lamp. Punch a hole in the top of electrical box that I just bought. Guide the cable behind the wall to both boxes.
  5. Buy a 15 Amp GFCI protected outlet because GFCI is mandatory for outdoor outlets. Connect all 3 wires to it and screw in to electrical box. Splice all 3 wires on the other end to the lamp wiring.
  6. Buy a Plastic Weatherproof in use cover and attach it to electrical box. In-use is mandatory as I would leave camera plugged in at all times.

Am I missing something? Do I need wire clamps too that would lock wire in the electrical box? Do I need to apply silicone caulk somewhere? Is it ok to install outlet that high above the ground? Are parts that I plan to order compatible with each other? Do I need to check wiring going from light switch to the lamp if it can actually handle 15 Amps?

The fuse in electrical panel is rated for 15Amps. At the moment I don't know how likely it is that some other device behind the 15A fuse would ever cause consumption to go over 15Amps.

  • 1
    Is there an always-hot in that box, or just the switched-hot, neutral, and ground? Oct 23, 2019 at 1:41
  • @ThreePhaseEel it is switched-hot, neutral and ground. Oct 23, 2019 at 2:08
  • Im no expert but wouldn't that mean that the new power outlet will be controlled by the same switch for the light? Oct 23, 2019 at 2:25
  • 1
    @ThreePhaseEel I forgot to mention that the light in front of house has built in motion sensor. So while it is switched hot, I almost have never tured it off in last few years. Oct 23, 2019 at 2:34
  • 1
    The GFCI needs to be (WR) weather rated. I would suggest a metal In use cover or extreme duty (same thing) most of the plastic ones I see are broken including at my house I have been two lazy to put the metal one on yet the kid that mows my yard broke it long ago.
    – Ed Beal
    Oct 23, 2019 at 13:30

2 Answers 2


As a related by separate issue regarding the camera USB power. If it were me, I would not put the USB power adapter on the outside of the house under the in-use cover like that (even if you found one with room under the cover). My reasoning is because if the camera is for security, all someone needs to do is unplug the USB adapter and it is dead!

The USB wires themselves are "low voltage", meaning most of the wiring rules don't apply. So what I did on mine was to put the USB power adapter INSIDE of the garage plugged into an existing outlet, then just drill a hole in the wall for the USB cable to pass through to the camera base with nothing exposed and visible. You can seal around the wire with some simple silicone sealant.

  • Thieves could also unplug the USB cable on the other end where it goes into camera to achieve the same outcome.. Really the only solution is to stream live data to a remote server or hide the camera or put camera in a place where it could not be easily reached (like very high or behind a window). BTW, I already reflashed the camera's firmware to operate as RTSP server and have Home Assistant to connect to it. That is on my todo list to figure out how backup'ing should be configured with Home Assistant. Oct 24, 2019 at 5:01

I've done this a couple of times. You are on the right track.


  1. electrical tape for taping wires together

  2. box (you might get away with old one that's already there)

  3. new cover for outside (get the once that have a break away tabs on bottom so you can have it closed and something plugged in)
  4. GFCI outlet (it'll come with everything needed, screws, twist ties, etc...)
  5. A nice set of electrical pliers to clean and cut wires as needed.


  1. turn off power to the switch (you can plug something in and see if it turns off when you flip the breaker)
  2. attach new GFCI to the existing box, usually you connect ground wire last. There should be 3: line (black hot), load (white neutral) and ground (green)
  3. secure the GFCI with screws
  4. attach the cover on top
  • but then I would have to remove the lamp, if I would reuse the same electrical box, no? I want to keep it, Oct 23, 2019 at 4:37
  • 3
    Don't use electrical tape to tape wires together. In permanent installations, electrical tape is for identification and for extra protection - use wire nuts or other approved connectors to connect wires together. Oct 23, 2019 at 5:33
  • 2
    Agree on wirenuts and the sequence of connecting the wires doesn’t matter at all just make sure hot , black wire is on the brass line screw and the white , neutral wire is on the silver line screw.
    – Ed Beal
    Oct 23, 2019 at 13:35
  • Manassehkatz, you do use electrical tape first, that's the first step. Wirecaps are the later step. You need both because usually the wirecaps are not as long as the exposed portion of the wire, so I tape enough of it to never get exposed. :)
    – Chris
    Oct 23, 2019 at 22:15
  • @Chris From what I have learned over the past couple of years from Harper and others, you want to strip the "right" amount - so that you get maximum contact inside the wire nuts but without any exposed conductors. Sometimes that means trimming 1/4" (or whatever) to make things just right. Oct 24, 2019 at 1:30

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