I’m trying to install a White Series Dimmer (2-1) Switch (VTM31-SN) in a single pole configuration. The existing switch box has two single-pole switches, each for a different load.
I can’t tell which wires are which. All the wires have black insulation, except the ground which is bare. On top of that, everything is coated in wall paint from when they sprayed. There are four wire nuts in the box, three of them red and one yellow.
How can I tell which wire is which? See photos. I’m trying to replace the switch on the right.
The school answer is you should use a meter to identify which is the line and which is the load.
But since you had the foresight to take pictures of the existing switches before you removed them, your line is the bottom conductor on both switches and the load is the top connector on both switches. I am basing that on the fact that the bottom screws on each switch are connected together. While I can’t really see into your box, that suggests a neutral installation. You need to test to be sure.
I’m going to guess that your neutral bundle is in there buried. It will be a bunch of whites wire nutted together.
That electrical box is overloaded. Code provides for box capacities based upon the number of conductors and other things, as well as the cubic capacity of the box. Yours isn’t even close to having the proper number of conductors in it. It looks like it is being used for both a junction box and for the switches.
The idea of box capacity is to ensure there is sufficient space to accommodate the heat generated by devices and conductors. Obviously, a box at overheats is not a good thing.
I would suggest that you consult with an electrician to ensure your box is within its capacity work to get assistance in sistering or adding a larger box to provide for all of those conductors.
I suspect this circled is the white bundle in the back of the box. You have Romex wire installed and there is always a black and white wire in 14/2 or 12/2 wire.
