0

I'm building a cabinet with a light in it, and I have 2 micro switches that will allow the light to turn on when a door is opened. (It's a standard micro switch with a normally-open side and a normally-closed side.) But I want the light to turn on when either switch is on in case only one door is opened. The problem is that would create a "loop" for the hot wire. If both switches are on then the hot wire will split to go to each switch, but then come back together to power the bulb. (See diagram.) Is there anything wrong with that setup?

I'm in the US and this is a standard 120V AC bulb. The two hot wires are coming from the same outlet so they'll necessarily be on the same phase.

wiring diagram

GJK
  • 101
  • 1

2 Answers2

3

You can absolutely do this.

You just have to be careful about the path the wires take.

All the current must flow on the same cable or conduit

so it goes something like this:

The cable between the two switches must have 3 power conductors so unless they are both in the same junction box you'll need /3 cable for this stretch.

enter image description here

Jasen
  • 26,920
  • 1
  • 24
  • 46
0
  1. If you use a relay with low voltage switching you can do this with no concerns. You can wire the low voltage switches any way you want safely. (See note below).
  2. Legally: If the cabinet is built-in it would be governed by building regs and you just can't do this. You should just run two switch loops from the bulb. If it's free standing, so long as you don't sell it, you can legally build whatever you want in a box. You need to worry about its safety but there are no regulations guiding you.
  3. Safety: If it's just one light bulb, probably an LED one, the current involved here isn't going to cause a problem. Anyway if your doors are all in a straight line, like any typical cabinet, it would be easy to do this without creating a loop. Just run the neutral along the front of the cabinet past both doors. .... but now you're putting junction boxes in the cabinet. We go back to "why not low voltage"?

Note: If you use LED lighting it's tempting to put the switches on the low voltage side of the power supply, thus avoiding all questions of safety and regulation here. But I recommend against that. It's very easy to find relays that will use low voltage to switch 120V. OTOH if you're switching on the low voltage side, the current is relatively high and the switches are hard to find and expensive.

jay613
  • 49,543
  • 6
  • 70
  • 201