3 wires, 2 switches, 1 problem!

Question

My friend had a stacked light switch in his kitchen, 1 switch operated the can lights, 1 operated the pendent lights. No 3 way lights, that’s the only switch there, tab broken off between the 2 stacked switches, he took it all apart before I saw it and mixed all the wires up. 3 wire bundles coming into the box, each with 1 white, 1 black, 1 ground, for a total of 3 blacks, 3 whites, 3 grounds. 2 of the blacks are hot, 1 is not. How can I wire this mess to operate 2 separate dimmer switches (Lutron Maestros)? Thanks!!!!!

Answer 1

A broken tab and 2 hot wires suggests you have more than one circuit in the box.

The first step is to identify both circuit breakers. Despite what was posted in another answer, you should not randomly connect wires together if there's still any chance of shorting two different phases together.

If you do identify 2 circuit breakers, and if they are not handle tied, then the next step is to consider if the circuit(s) are safe. Any MWBC would require a handle tie. If there are two separate circuits with two different neutral connections to the panelboard, then that would not be a MWBC but could have other rules pertient to a duplex switch.

Answer 2

First identify the wires, with the breaker off choose 2 bundles and connect them together (black to black, white to white) make sure the one you didn't choose cannot short against anything. Then turn on the breaker, if either of the lights turn on then the one that doesn't light up is the bundle that you didn't choose, if neither turn on then the one you left unconnected is the power from the panel. Do that once more to figure who which of the connected bundles is which.

Knowing that you can connect dimmer switches as normal, power from the panel to the line side and the wires to the lights to their respective load side.

If there are multiple line connections you pigtail them from the wires from the panel.

All grounds get connected together.