enter image description hereI haven’t heard from the electrician who wired my house for 5 days and prior to that was just a short text to say our contract didn’t include installing light fixtures for a remodel. I live in a rural area, so contractors are hard to come by. I can do basic wiring.

My questions concerns electrical boxes for PPG fiber cement light blocks and outlet blocks. The blocks are trim pieces for outdoor electrical fixtures. They have very narrow and shallow openings.

The light block is 1.25” thick x 7.25 wide x 9.5 high. One block has 2 cables protruding and the other has 1. A 4” diameter pancake box was slightly too large in diameter.

My light fixtures are Bellagio 16.5" high, bronze downbridge outdoor wall lights. The backplate is 6.75" high x 4.75" wide. They weigh 4lbs.

Question: What type of light box should I use to enclose my wiring? Should I use a metal 3.5” octagon box 1.5” deep? I want the light fixture to sit flush with the trim.

The outlet block is 1.25” thick x 5.5 wide x 7.5 high. I tried a 1 gang, 1” deep blue PVC flanged shallow box, but it was too wide. I found a metal box that will fit, but it is 1.5” deep. I was hoping the face of the GFCI outlet would be flush with the trim. The outlets will be protected by waterproof boxes.

Question: What type of outlet box should I use? Should I stay away from metal? Also, one outlet block has 3 cables protruding from it.

Question: The final question concerns how the cables protrude from the sheathing. In several cases they’re not in the center of the opening. Should I use a jig saw to cut into the sheathing to reposition the cable to be able to pass through center knockouts?


  • 1
    It's common as dirt, but I consider extending indoor (non-wet-rated) NM-B cables to Exterior light/outlet positions a code violation, or at least a bad idea (i.e. even if someone has found an exception in code allowing it, it's OK to be better than code.) And as has been said many times on this site, put the GFCI inside, feed the outside outlet(s) from the Load terminals (properly label them as GFCI-protected), it will last a lot longer indoors than out, even with a cover.
    – Ecnerwal
    Commented Mar 31, 2020 at 12:30
  • I suspect the proper approach to the trim/box issue is to modify the trim (and possibly increase the opening behind it, though that is harder with the wires in place) to suit the boxes you need - I don't really know, I don't deal with pre-made trim, and my building's aesthetic is fine with surface-mounted exterior boxes where I need exterior electrics. Pay attention to where the fixture's trim will meet the building trim so that you don't cut beyond that point, and any sins of imperfection will be concealed.
    – Ecnerwal
    Commented Mar 31, 2020 at 12:37
  • I must be missing something here but it seems that that isn't a proper termination for wire and that the electrician should have to add the boxes. Yes, the contract didn't include adding fixtures but the boxes should have been added. Get back with him again or get with the inspector. I've never left a job like that and every fixture I've ever installed (1000's) has had a box.
    – JACK
    Commented Mar 31, 2020 at 14:21
  • @jack if the job was “roping” the house or running wires only I have had this contracted out a few times as some of the young hungry electricians can do it faster than I can, in some states no license is required for just “roping” or pulling wire so I have used them to get the wire in then I go in and finish it out. So it depends on the contract.
    – Ed Beal
    Commented Mar 31, 2020 at 15:57
  • @EdBeal Ain't no rope'n done round here boy.... we're city slickers.
    – JACK
    Commented Mar 31, 2020 at 16:01

1 Answer 1


It would help to have a single question and focus on it , what is the question about 3 wires? I can see 2 on the top left and a loop on the right, is the question on how to wire?

I would use a round light fixture box inset in the wall For the upper boxes If the box is mounted in the wall NMB wire is ok but if the box is surface mounted then it comes down to local jurisdiction rules and amendments.

A wall pack normally needs no box, the connections are made inside the fixture, most lanterns more common with this setup will need a round box. Metal or plastic is your choice.

You mention receptacle / GFCI yes you will need an in-use or heavy duty cover and a weather rated GFCI if the GFCI is outside (many locate the GFCI inside for longer life but with weather rated it doesn’t matter as the electronics are sealed).

I forgot to mention but many jurisdictions require tamper resistant receptacles on top of GFCI.

  • 1
    One important item to note for the OP: When shopping for the boxes, be sure to purchase "Old Work" boxes, despite the fact that this is brand new work. Old Work boxes are designed to slip into an opening in the wall and be fastened tight from the outside. New Work boxes have nails preinstalled in them and are designed to be nailed to the studs before any finish material goes up - i.e. you still have room to swing a hammer inside the stud bay.
    – FreeMan
    Commented Apr 1, 2020 at 11:59

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