First of all - I am turning off all power while doing work. I’m looking to replace 2 old dimmers (the ones that you spin) and I’m a bit confused by the old wiring. I’ve located the bare copper for grounds (sticking out and not connected) and the whites in the back for neutral. Can anybody provide insight on which is the load wire? I guess to truly determine this, I would need to disconnect all of the wires and use a non-contact voltage tester to find the single load wire. I would then loop from that one to the next. I’m just not getting why there are other wires feeding into the wall each step of the way (2nd connection from right one goes into the wall too). I’m also not getting how I would create a link between the units since I don’t really have a jumper cable to go from box 1 to box 2.
Any insight is appreciated - or maybe I’ll just call the electrician.
The black wires may be jumped together in the junction box if they are coming from the same circuit, but the each red wire is going to a different light fixture.
From the picture, the right-side switch should be the (spin) dimmer. I think the (left) black wire connect with other black wires would be the hot/load wire. The (right) black wire connect to black wire of light. Inside the box, neutral wire of light seem connect to other neutral wires. Is left-side switch control or dimmer 2 other lights ? If yes, then the red wire connect to black wires of other 2 lights. If no, then it would be a 3-way dimmer that 2 red wires connect to another 3-way switch/dimmer to the light
I’m not an electrician. And it’s never as clear to trace the path of each wire in a picture as in real life.
But I think it’s possible you have hot wire coming from the middle connected to black wires on each dimmer with a wirenut. Then you have load wires from each dimmer going out towards the left and right (red on left, black on right). Then you have a few bundles of neutral wires. The dimmer on the left has a traveler wire with a wirenut on it that’s not connected to anything.
The only way to figure it out for sure is to use a multimeter, with at least a basic understanding of household electrical circuits. I’ve tried a couple electrical projects with ST but I think for anything else I want to add, the expense of an electrician is worth not dealing with the hassle or potentially risk.
The very right nut is the load for that switch, second from the right is your line/supply for both switches. Assuming the left switch is part of a 3-way, the second from the left is the load for that switch and the very left is the traveler. That’s my guess
I always find it helpful to pull the wire bundles out of the box and look at each individual run of cables to figure out the connection as it is often not clear.
Each load needs a hot (black) and neutral (white) and ground (bare copper). There may also be a red traveler for 3 way fixtures which can also be hot. The white and grounds will be bundled together.
You will likely need to pig tail a white and a ground from the big bundles to put a newer smart switch in.
For the load you will need to determine which black line is hot and which black line is switched. Often a box will have one hot line coming into the box and the other black lines will be from the fixtures (load)… but just as often there can be multiple hot wires coming into the same box. Something as simple as a non contact voltage sensor can help you a lot to determine this by cycling the switches and shutting off the breaker(s).
In your case the hot line into the box looks like its the one connected to both dimmers. The black line on the right for the dimmer on the right is the switched load. For the dimmer to the left it looks like a 3 way so ensure you buy a 3 way smart switch. One is load and one is a traveler… its hard to tell which is which from this camera angle.
The way I see it, the one on the left has a traveler wire that’s connected - hence my question, is this a three-way setup? Older dimmers do not require a neutral wire, they act as variable resistors in series with the bulb.
