There's a set of exposed THHN cables before they enter a junction box below my home's load center. The wires are currently capped so I wanted to know what the risk was of having this gap when/if the wires are live and what I can do to remediate it.

junction box before load center

close up of gap

capped ends inside load center

conduit terminating into ground below concrete

  • 1
    This question is, unintentionally, too broad and needs focus. You've got two great answers for the "Do I need to and if so how do I protect these wires in this exposed bit of conduit?" question which you didn't really but sort of did ask. I recommend that you edit this question down to just that so that the answers apply, then ask the rest of it in a new question (and mention there that the exposed conduit it addressed elsewhere).
    – FreeMan
    May 27, 2022 at 14:48
  • Thanks for the recommendation, I’ll go ahead and add an edit tag with this info. I actually did intend to make it a broad question framed as “how would you best utilize this cable run?”, though without the complication of exposed wires and that’s certainly the greatest concern at this point. May 27, 2022 at 15:09
  • 2
    A) No need to flag things as "edit" or "update", one can simply click the "last edited" date if he wants to see the edits. B) "What's best" also has a high likelihood of being closed as being opinion-based. Make it "Here's my plan, will it work or are there issues?" and people will comment and make alternate recommendations if they deem it necessary.
    – FreeMan
    May 27, 2022 at 15:17
  • 3
    Excellent! Sadly, too many people just walk away when asked for updates. Glad you didn't!
    – FreeMan
    May 27, 2022 at 16:28
  • In photos 1 and 2, is the insulation damaged even with the top of the pipe? Can't tell if its abrasion through insulation, or just paint. If its damaged, then you may need to pull the wire for replacement or at minimum for sealing each with suitable heatshrink.
    – Criggie
    May 28, 2022 at 22:55

4 Answers 4


The conduit entering the box evidently needed, but someone thought it didn't need, an expansion fitting. They appear to have also skipped glue, as I don't see any remains of glue or broken conduit in the hub.

An expansion fitting is just a long sliding joint with hubs on both ends. Adjust it to the middle of its range (make a mark), pull back the wires so you can cut the conduit to install it, cut out enough conduit to provide space for the expansion fitting, cut a stub of conduit to glue the one end of the fitting into the hub on the box, and glue the other end of the fitting to the conduit in place. You can do that because the fitting slides, as it will in use.

Then pull the wires back in.


From looking at your pictures in the question it is not certain just where the vertical conduit below the box terminates at the lower end. I bring this up because it is possible that the conduit extends down into the ground.

It is possible that at one time the gap was not there and the conduit mated into the fitting on the box. The ground near the side of the building may have settled over time pulling the conduit down at the same time. If this is the case it may be a simple fix to dig down around the conduit to the extent that it can be pulled back up enough to close the gap. In doing so it would be necessary to backfill around the conduit in a way to support it so it stays up. This would be especially important it the portion of the conduit has a turn and travelled horizontal below grade.

  • I agree.This was the first cause/solution I thought of...
    – JACK
    May 27, 2022 at 18:05
  • I added another picture that shows the conduit going into the concrete on the ground. It would be a major project to dig that up so now I'm wondering if this is even salvageable based on the other answers. Thanks. May 28, 2022 at 3:55
  • 1
    Yes, it's salvageable. Scraping paint off conduit (for the distance required to make a glue joint) is not that big of a deal. For that matter, PVC cleaner may just peel the paint right off, if you follow the cleaner/primer/cement path to good joints - worth a test, anyway.
    – Ecnerwal
    May 28, 2022 at 15:02

General thoughts

  1. The main risk on the uncovered wires is damage. If something hit that wire just right, it could penetrate the insulation and kill someone. Even though THHN is hefty stuff, I would try to protect it somehow. Either lower the box or pull it off so you can add a proper extension. Looks like PVC conduit so not expensive to do either way
  2. The wire is more than sufficient for your 40 amp draw. I would downsize the breaker to 40 amps, though.
  3. If you followed step #2, you can now switch to 8-8-8-8 XHHW aluminum cable to run to your range (far cheaper than copper). Buy some Polaris connectors to join the two sets of wires safely
  • 1
    Point 3 is unnecessary, it seems, since the OP already has wire in the wall.
    – FreeMan
    May 27, 2022 at 14:49
  • 2
    Correction: Point 3 is valid but unnecessary...
    – FreeMan
    May 27, 2022 at 15:18
  • @FreeMan It sounds like he still needs to get cable from this box to where the range is. Hence my #3 (that does not look like 10' of wire, but I could be wrong)
    – Machavity
    May 27, 2022 at 16:37
  • Ah, fair point. Usually I see "buy AL" and think of it as a long run, high amperage recommendation. My bad.
    – FreeMan
    May 27, 2022 at 17:31

This is very bad, and was "amateur hour" from the day it was built, and you can tell because it was like that even before the painters arrived. The builder should be held accountable.

You will need to disconnect the 4 wires from wherever they are attached (whichever end is most convenient), straighten them out, and overlap one of the wires with a pulling rope for about 12 inches. Aggressively lash them together with tape so they can't pull apart. Then lash the other 3 wires to the bundle, and tape down the ends so they can pull easily.

Now, pull the wires back so they are clear of the work area. Make full use of all existing pulling points (e.g. an LB on the interior). To the extent practicable, work around the rope.

You may need to pull the rope through this box to replace the box, since the lip of the hole is now contaminated with paint, and won't fit the pipe anymore. (unless you want to lay there on your back with an exacto knife chiseling all the paint off the interior of the port, yikes). Cheap plastic box (cheap in quality), they don't age well.

Then dig up the conduit below the ground (to where it isn't painted) so it will fit in PVC fittings and be glueable. Unless you want to painstakingly strip paint off PVC without damaging the PVC! Better to go a bit below ground.

Then replace the PVC vertical run with Schedule 80 PVC, which is what should have been used in the first place. You'll have to go to an electrical supply or good lumberyard for that, box stores don't sell it. This time, properly fit it all the way into the box! And make sure the vertical run has an expansion joint, installed per instructions.

An expansion joint is a trombone slider that allows for pipe movement due to thermal expansion and settling. Place it so it's halfway (not at one extreme or the other, that would defeat the purpose).

Once everything is fitted up, glue it up (otherwise the expansion joint will let the pipes slide out).

  • 2
    It is possible that the painters were doing a spray job to re-paint the house / building years after that electrical box and conduit was installed.
    – Michael Karas
    May 28, 2022 at 9:10
  • It's likely that the conduit was in (but apparently not glued, or not glued well at all) the fitting when the place was built, settling occurred and pulled it out, (which is why we use expansion fittings, especially in places with freeze-thaw) and then the house was repainted one or more times over the decades.
    – Ecnerwal
    May 28, 2022 at 15:11
  • 1
    @Ecnerwal true... although PVC is not glued, it is welded. The "glue" is solvent which melts the plastic and causes it to become one piece of plastic. I would expect any parting to be extremely gory. May 28, 2022 at 20:02
  • 1
    +1 for "Aggressively lash..."
    – Criggie
    May 28, 2022 at 22:53

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