I have a 24VAC transformer that I plan to use in a shed for powering landscape lighting, WiFi cameras, sensors, etc. I had been powering these things from my irrigation system transformer, but I'm too close to overloading it now.

Here's how I have the transformer positioned now, and how I plan to connect it with conduit:

conduit diagram

The red lines for the 110VAC conduit go behind the irrigation box door even though I drew them in front. The yellow line will be PVC conduit that connects to the existing low-voltage conduit going to the irrigation box (that's where all my direct burial wires to my gadgets come in). I'll replace that elbow with a "T".

Two things seem a little janky about this setup:

  1. Those single gang boxes are a little loose on the transformer. I took the lock nuts off the transformer and just screwed the boxes on directly. However, I can't screw the boxes on tightly or they'll be at odd angles.

  2. The transformer is deeper than the boxes. This means that the boxes just hang off the transformer:


There's roughly a 3/4" gap between the box and the wall. I could put some wood behind it to stabilize it, but something tells me I'm just not using the right parts for the job here.

Disregard the exterior siding: This is inside a shed (attached to the house) with a not-so-weathertight door. I'm guessing this is a "damp location."


Here's a photo of the knockouts on the bottom of the box. If I were to directly connect the new transformer to the irrigation box, I think I'd connect to the second knockout from the far left and move the existing low-voltage wiring to the knockout on the right.

bottom of the box

  • @Ruskes: Are you asking if I've found a box or NEMA cabinet to put my new transformer in? No. Maybe that's the way these transformers are really supposed to be installed?
    – watkipet
    Jul 9, 2023 at 3:36

2 Answers 2


You know that water pipe is not conduit, right? That's the most janky thing here by far. Those plumbing elbows make pulling wires impossible. I could care less on 24V wiring, but don't be seen doing it on 120V.

I would consider mounting the transformer directly on the plastic box. If needed, add an offset nipple and a threaded coupler to mount it slightly below.

  • Yeah, I know it's not conduit. I thought that must just be common practice for irrigation installers. There are more sins that came with that shed: exposed NM-cable, dry location plastic boxes, stripped NM conductors dangling through knockouts with no strain relief. I'm hoping to fix some of those. I think I'll go with your idea of the offset nipple and threaded coupler. BTW, I added another photo of the bottom of the box.
    – watkipet
    Jul 9, 2023 at 3:30
  • 1
    @watkipet yeah, that NM cable is also a problem. Not least, it's not rated for outdoors. Jul 9, 2023 at 7:55

Get a 6x6x4 PVC J-box and put everything inside it. Use one of the 1 gang boxes to split line voltage with one tail feeding irrigation and one the isolated transformer

  • 2
    No. That's a huge code violation. The 120VAC systems and the 24VAC systems must be entirely physically separated in order to be allowed to use low-voltage wiring methods on the low-voltage side.
    – nobody
    Mar 10 at 13:12

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