I recently bought a new house. I know enough about electrical codes to know that some of the homeowner's own electrical add-ons are not done "the right way". Nothing terribly dangerous immediately (given I don't have any children in the house to worry about) but definitely something I want to fix up and do more correctly soon-ish. I would like to keep all the previous homeowner's additions but wire them up right.

Here's the first bit: Switched outlet

As you can see, the previous (late) homeowner added a switched outlet in the garage (which is "finished" in that there is drywall but it's not painted so sort of a semi-finished area). The switched outlet controls an overhead light via the extension cord you can see plugged into it. However, the outlet itself is connected into another in-wall wall outlet via a homemade "extension cord" made with NM cable.

Q1: How would you connect power to this (cabling methods, etc.). I'd prefer not to tear up the wall though I'm open to it if there's no other way. And I'm perfectly happy to open up the existing "supply" outlet and do whatever with it.

(I had seen an idea in another posting that it might be possible to add a metal extension box on top of an existing in-wall outlet box and turn that into a jbox for further distribution. But also, this may bleed into my next question below.)

The homeowner also installed four metal electrical outlets into this massive workbench. One example shown here:

Outlet in work bench

These are extremely handy. However, note that they're also supplied with NM cable (routed from a single large junction box on the back of the bench, which you can see part of in the picture).

The power to that large box is being supplied in the same way: via another homemade extension cord, also built from NM, and connected to another in-wall outlet, which is just below the other one above. You can just make out at the bottom of the next picture.

Supply to workbench

Now, the workbench is not actually permanently attached to the wall (however, it is damn heavy: I can just manage to scoot it by myself, by which I mean that I'm not terribly concerned with someone inadvertently moving it or it falling over, in case that factors into your advice). I suppose it could be permanently attached, and if that's the only way to do this "correctly", I'm willing to consider that.

So my other questions:

Q2: What methods can I consider to supply power to the workbench? Is it permissible to have a proper "extension cord" that supplies power to a "detachable" piece of furniture like this?

Otherwise, this also possibly links to Q1 above because ideally if I can extend/rework one of the in-wall boxes as a base jbox for power distribution to the other outlets, I would only do that once (preferably in the lower box) and supply all the other outlets from that.

Q3: Once I manage to get power to the big junction box on the rear of the workbench, what would be the best way to route from there to the other metal outlets mounted onto the workbench? Would you use AC? Or MC? Or...

I'm interested in general ideas, suggestions, etc. in addition to specific answers.

  • 1
    Those "extensions" should go and the boxes be wired correctly. NM cable below 8 feet should be protected, in the wall, in conduit, probably even plastic pipe cut in half, also there are wall mounted systems(wire mould?) Garages are suppose to be GFCI(breaker or outlet) protected now.
    – crip659
    Commented Jul 21, 2022 at 0:32
  • If you haven't already, make a list of the circuits in your house, including the ones here. For each, you'll want to note the amperage of the breaker, the type and gauge of the wire, and what outlets/light/switches it includes. That way you can identify circuits that are perhaps already overloaded or wrongly wired and need changes before you invest time and effort in the receptacles.
    – Armand
    Commented Jul 21, 2022 at 18:19

1 Answer 1


For the first bit, extension box to EMT conduit run on the surface to avoid opening walls (or wiremold if you like, but it's a workshop area so EMT seems the best way.) THHN wires in the conduit. If you connect it up properly (tighten the fittings) you only need two wires, as the conduit itself will carry the ground from the extension box (connected to the ground wire in that box.)

For the second bit, it can be left detached. The wiring between the outlets and the junction box can be NM (as it is fixed) but there are areas where "protected from damage" might require something to do that, the way it's laid out. Replacing that with EMT or armored flex cable would be a different approach. Relocating the junction box inside the frame would make it more possible to route the NM in a way that I'd consider "protected from damage."

Not clear if you need anyone else's blessing on that if it's not part of the building, probably depends on LAHJ.

The cord feeding it needs to be changed to cordage (flexible cable intended for things that move) or you put an "inlet" on the junction box when moving it to protect your fixed wiring and just use an actual prebuilt extension cord (which are made from cordage.)

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