So I was close when I cast this 3/4" sch40 PVC in concrete - but not close enough!

I'm roughing in an 110v electric radiator here with a single run of 12/2. Where I want the box to interface with the radiator knockouts isn't quite right. Looking for suggestions to get the box into the right spot...

Some thoughts I've had:

  1. The bottom knockout will only be 2" off the ground, so even if I could bend the PVC somehow - there isn't enough room to get it aligned. I've only bent PVC where I can stuff it with sand and use a heatgun to it doesn't deform - and where it's installed, I'm not confident I won't screw it up if I try.

  2. The back of the box is too close to be able to get a stock 90 bend in there and enter via the back.

  3. I've never used it - but maybe I can transition to liquidtight and make some kind of whip that enters from the top?

  4. I could abandon the idea of this being 'conduit' and think of it as a protected raceway, cut the PVC flush with ground and stuff a 12/2 romex down there instead of THHN.

Any other ideas from the pros and gurus? Cheers!

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  • 4
    How about using a 2-gang box with 2 or 3 knockouts on the bottom?
    – brhans
    May 19, 2022 at 1:04
  • @brhans interesting thought. maybe a 2-gang with a extension ring and then finish it with a 52-C-10 device-offset-ring might allow me to enter from the bottom. wish i lived near a real electrical store... May 19, 2022 at 5:18
  • How about installing the radiator 3/8" to the left? (It looks like you're off by about 1/2 the 3/4" conduit width...)
    – FreeMan
    May 19, 2022 at 13:11
  • @FreeMan Yeah - I think you are right and using an extension ring. Have tight clearances on radiator - but I think it's close enough to wiggle left a bit and just enter from bottom at correct height with extension. sometimes i can't see the forest for the trees. May 19, 2022 at 16:29

2 Answers 2


I'd suggest moving the radiator the 3/8" or so to the left (as seen in the picture) and mounting the box on the conduit where it is. Unless the radiator is wedged against the wall or other immovable fixture in the bathroom, this would, most likely, be the easiest solution.

Use extension rings, etc. as necessary to make up the final connection to the back of the radiator.


People always go for those "handy-boxes".

Nope... go for a "4x4 metal box with a 1-gang mud ring".

enter image description here

That will provide pretty much exactly the hole offset that you need.

It will also have at least one 3/4" knockout, so you aren't trying to hack-a-dack a 3/4" conduit into a 1/2" KO.

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