I'm replacing this simple 2-connector light switch with a 4-wire dimmer. The 2 new wires present on the dimmer are neutral and ground, and only neutral has an obvious home. The box has no visible ground wires. Can I safely ground the dimmer to a box screw or leave the dimmer ground wire disconnected?
Best Answer
That wiring is AC cable, modern AC cable. I can clearly see the bonding strip that makes the sheathing a grounding conductor. So since a grounding means exists you must use it.
With switches, simply screwing them to a grounded metallic box grounds them, as opposed to a receptacle which would need to be a self-grounding type. So technically, just installing the switch would be adequate, but since there is a ground wire from the dimmer I would connect it to the box.