Switch – Dimmer switch not connected to ground

The loop in the black wire is normal when electricians are running a hot wire from device to device. It saves them time and is really safer since it involves fewer wire nuts.

The orange wire is the wire that is going to the light. The power enters the switch where the black wire is looped over the screw, and exits to the light through the orange wire.

Yes, attach the green wire to the green screw. But, you need to wire the blacks from the switch differently. One switch black is for the incoming power, and the other is for the exiting power. So, one needs to be connected to the same black that is connected to the old switch; and one needs to be connected to the orange.

I would, with the power off at the circuit breaker panel, and after testing to make sure the black at the switch is not hot, cut the existing black to form two separate wires and strip the ends appropriately. Then I would connect one of the black wires from the new switch to these two wires with a wire nut. After that, connect the other black for the new switch to the orange with a wire nut. That should do it, and your dimmer should now work. Good luck, and be careful!

PS: I personally use a Fluke 1AC-A1-II Volt-Alert AC Non-Contact Voltage Tester to verify or locate hot wires and love it. You might want to check it out for the future. Its inexpensive too. Note: I have no personal connection to Fluke; I just think good products like this are worth spreading the word about.

I'd be surprised if the wires coming in from the bottom of the box (the 14/2 NM) weren't the supply (hot). It's fairly common to use a 14/3 for the run between the switches and the light\fan. In that you only have 2 cables coming into the box and you're working with single-pole switches, the easiest way to verify is to use the regular switch to test for the hot.

I'd connect one of the non-green terminals to the red wire coming in from the top and one of the non-green terminals to the black wire coming in from the bottom. Switch it on, and turn the breaker back on. My guess is that either the fan (most likely) or light will come on.

You can then confirm this by turning the breaker back off, removing the red wire from the switch, and replace it with the black wire coming in from the top of the box. Turn everything back on, and the other device should be on now.

After you've confirmed that the bottom black wire is the hot, follow the installation instructions on the new switch and dimmer. You'll need to connect both of line terminals on the switches to the hot. You can either jumper them (tacky) or wire-nut two pigtails onto the hot and connect one to each switch.