No neutrals in switch boxes. But what about outlet boxes?

wiring
switch
project_lighting

(Mark) #1

I’d like to have better control of my lights with ST, but most of my switch boxes have no neutrals and that makes things more complicated. If I have a switch box in the bathroom that has a GFCI receptacle and three switches, then I have to have a neutral wire in that box for the outlet right? Tagging @Navat604, Ray I’d appreciate any thoughts you have. Thanks in advance.

In the pics below the receptacle has one white and one black wire attached. The black wire goes to a wirenut that’s joined with a black wire to the switch immediately to the left of the outlet (control for an exhaust fan) and the line coming into the box. At least that’s what I think, because that bundle of black wires is hot when I check with a multimeter.

The white wire from the receptacle also goes to a wirenut joined with two other white wires; they each enter the box from separate bundles. I think one white wire is coming from the ceiling fan, and the other goes back to the circuit breaker, i.e. neutrals. That white bundle is not hot when I check with a multimeter.

I know the pics probably aren’t great but I was trying to figure it out without unscrewing all the switches. But I should be able to replace the ceiling fan switch with a smart switch, right?


(Chris) #2

Yep, looks like you have neutrals available in that box. If you run the multimeter across the black and white wires you should see 120v. The exposed portions of those hot wires are kinda scary, try to cover those up with the wire nut when you put everything back together.


(Ray) #3

You are right about the wiring. It’s exactly what you described above and you should be able to I stall smart switches.
As for the exposed wiring. You can cut back the conductors a little or electrical tape the wire nuts. Could be OK with your dumb switch or plug but the new smart smart is way thicker will really hard on your wire nuts.


(Mark) #4

Thanks for confirming. There are also two other light switches in the gang box that I think are on a different circuit than the fan and receptacle. Is there an important reason not to put smart switches (or maybe a dual relay) on that circuit and connect the neutral wire to the fan/receptacle circuit?

Re: the wire nuts. I’ve noticed in several switch boxes that whoever did the wiring when my apartment was last renovated (the building is probably from the 1920s) was a little lazy about allowing exposed wires like that. It’s annoying to think about, but I don’t have the motivation to check every switch/outlet box and fixture to try to fix them. No electrical fires or shocks yet at least :grin:


(Ray) #5

There are a couple of reasons not to connect two different line hot circuits together.

  1. Your neutral is rated only for 15 amps. Two different line hot circuits equal 30 amps.
  2. If the 2 line hot circuits are on different phase. Then you have a short circuit. When both loads are on.
  3. Your GFCI will trip due to higher voltage leaks.
    If needed you can use 2 different neutrals on the same line hot.

(Mark) #6

Alright thanks for the info. Guess I’ll stick with just the one smart switch to control the bathroom exhaust fan.


(Eric) #7

My basement lights didn’t have neutrals and through some investigation I learned of some major wiring issues the previous owner did as well as 15 recessed lights wired with 6 wall recepticles. This is the ceiling now…


(Ray) #8

Now that’s one crazy way to find out about neutral. Hope your spouse won’t be upset :laughing:


(Eric) #9

She is cool. She was happy as I found a lot of un safe stuff. For example, hot wires that just ended above the ceiling without being contained in a junction box or even with without wire nuts. Plus now I am going to spray foam the the sill plate.


(Ray) #10

Unfortunately it’s pretty common for older home to have these type of issues. That’s an interesting stringer framing for your basement ceiling. Plenty of room. You can go crazy with wiring now.


(Eric) #11

Yes lots of options now! That beam going left to right is cosmetic.