I tried to install an outlet on existing junction box as below, but failed because it's too small to put in. I have 3 solutions to think.

  • Remove junction caps and put 2 outgoing lines into backstabs and screws, so it works as junction
  • Buy conduits and extend another box on the top
  • Replace existing box to bigger one (I can't.. because I can't take out the box from bottom conduits)

Can you tell me which is the best(means easiest) solution? (You can put your own)

Existing Junction Box

  • Looks like loads of room. Are you trying to install a GFCI+receptacle? If so, where do those two conduits go? Anywhere that's indoors? Nov 26, 2018 at 17:07
  • Yes, it's a room issue. I bought non-GFCI because of the space problem, even small tamper resistant outlet is too big for the 1-gang box. (I guess) two conduits go down to land for outdoor lights.
    – Won
    Nov 26, 2018 at 17:18
  • Those wire nuts need to be pushed into the recesses in the back, the position of that ground nut won't do. I gather this box did not have a receptacle before. That particular model is also the fattest nut on the market, could another brand or size (e.g. Yellow) be used? Nov 26, 2018 at 17:36
  • I think it is always a good idea to use a GFI for outdoor service; and required by many jurisdictions. Nov 26, 2018 at 17:51
  • 2
    @blacksmith the requirement is for GFCI protection on that circuit, not a GFCI device in that location. GFCI devices can extend protection to the rest of the downline circuit, so the best play is put the GFCI indoors in the line that feeds that outlet, either as a receptacle, deadfront or breaker. That gets it out of the weather, which is very damaging to even "outdoor rated" GFCIs. Nov 26, 2018 at 18:43

3 Answers 3


That box has plenty of room, but you need to be strategic in where you place the wire nuts. There is a hollow in the middle of the box, and they should be pushed back down there. It also helps to use a less bulky model of wire nut. Ideal brand is popular among electricians.

As far as GFCI, don't put a GFCI here. It's outdoors and the GFCI will quickly corrode and fail.

GFCI devices are able to protect a downline circuit, e.g. A GFCI circuit breaker does exactly that. So follow this circuit back toward the ser ice panel. If it makes a stop at an indoor receptacle, fit the GFCI there and place this downline on its LOAD terminals. Many people use those terminals accidentally because they don't know any better; use them deliberately. Or you can use a GFCI breaker.

Then, fit a plain receptacle here and place "GFCI Protected" stickers here and on any other receptacles that are now so protected. Those are included with the GFCI.

Lastly, fit an outdoor "in use" "waterproof" cover. They don't work, but they're required by Code. The GFCI inside the house will do the protecting of all the wire in this box including the LINE side wiring (which a GFCI out here can't protect).

  • The only comment I would make is to make sure that the GFCI can be located inside my AHJ requires them outside if not within 5' of the closest door, this was explained to me that they don't want folks using other outlets because the GFCI is a pain to reset.
    – Ed Beal
    Nov 27, 2018 at 0:29

If it really won't fit get a extension for a bell box (weatherproof). Also it should be a weather resistant GFCI outlet. last an in use cover or extra duty this protects the outlet from splashes, the weather resistant GFCI has the electronics potted or encased so moisture won't cause failures. I put a gfci in that exact type of box last week , Using a smaller wire nut may help there but I think I had tan and red wire nuts on both the hot and neutral pigtails and it fit.


If there's no upstream GFCI, you need to have a GFCI and it needs to be weather resistant. For this case, I would recommend the Leviton Weather Resistant GFCI because they made it slimmer and you might have better luck in getting it into the box.

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