Trying to connect the 4 11/16 SQ deep box to the Main Panel. I'm using THHN wires thru out to minimize splicing. Since THHN needs to be inside conduit, I was thinking of using LB inside the wall to transition from junction box outside the drywall to the Main Panel. No splicing inside the LB, just straight/angle pull.

Is it to code installing LB inside a wall?

  • 2
    You can put it in the wall as long as the cover plate access is left exposed and accessible without removal of wall covering.
    – Kyle
    Sep 12, 2022 at 6:01

1 Answer 1


When running THHN wires in conduit, you must assemble all of the conduit complete & final, signed off, whole nine yards, empty. No wires in it. Only then do you pull in the wires. It's a bit of a "victory lap".

As such, the conduit must be built to be pullable. That means every access point (such as an LB) must be accessible forever without tools and without harming the building surfaces.

The LB is an access cover you must be able to access, sorry. Your plan won't work.

What you probably want is something like this. They're not permitted anywhere except at the very end of the conduit run at a box, where you can deal with its limitations by pushing wires and reaching in with pliers to grab the tape or wire end. It's not allowed mid-run, for instance - for that you use a proper sweep.


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