I’m installing a new dimmer switch into an electrical box where there is currently a dimmer switch for the light and a toggle switch for a fan. The existing dimmer was never connected to a ground wire.
In trying to install the new switch, I’m unsure which is the ground wire. There appear to be 5 bare, copper wires that are bound together at the end. Are these the ground wires? If so, how do I connect it and which one do I use? I’ve installed these before, but it’s always been straightforward.

Thank you!

 

Welcome to the forums.

I'd cut off that band on the ground wires (bare copper) and nut them all together with the ground wire from the dimmer.

 

The are the ground wires. All of them. Either cut them just behind the crimp connector, as Mitch suggested, or squeeze the crimp connector until it opens enough to be slid off.

You can't bond the box to ground because it's plastic, but you can and should bond the devices. Line the existing ground wires up and use pliers to give them a couple of twists, clockwise. If your new dimmer has a built-in ground wire, lay that into a groove in the spiral you've made. Assuming that your toggle switch doesn't have a ground tail, cut a piece of bare or green wire about 8" long and lay one end of that in a different groove. Give all seven wires a couple more twists, trim the ends if you need to, and screw a wire nut on the protect everything.

One question: The red wire nut protecting the neutral splice looks like it's showing wire through an open space in the side. Is it, or is that an illusion?

 

Worth checking but this looked like paint to me.

 

I agree, and that's why I brought it up.

 

Thank you so much for your quick & thorough replies. This all makes sense to me, so I’ll try it out. The wire nut is an optical illusion – I double-checked, but thank you.