thermostatthermostat-c-wire
I am upgrading to a new thermostat which requires a "c" wire to power it. I have an unused blue wire running from my thermostat to my furnace that I plan to use as the common wire. However, I am unsure where to attach the "c" wire at my furnace. Any help would be greatly appreciated!
Since in your case, one side of the transformer is grounded. You can simply use a fork or ring terminal, to connect the C wire to the chassis. Though it appears there's already a wire that's attached to ground, and comes right over near the thermostat wiring. I'd just put my C wire in with the other two wires, in that twist-on wire connector near the bottom of the photo.
You don't show where all the thermostat wires are connected in the unit, so I can't see how it's currently connected. But according to the schematic, the blue wire heading off to the left of the first photo is the C wire.
Best Answer
It's labeled in the diagram.
You should see a cable that leads to the A/C compressor,which contains 2 wires. One will be connected to the
Ywire from the thermostat, the other is connected to theCwire. You didn't include the make and model of the furnace, so I'm not sure if there's a terminal block or if the terminals are labeled.You'll want to make sure the transformer can supply the additional load of the thermostat, or you'll burn out the transformer. It's usually not a problem, but it's something to be aware of.
For more information, please see this answer.