If your system has a C-wire, it might be in use or just tucked away behind your current thermostat. If your system doesn’t have a C-wire, you’ll need to run a new cable from your furnace to your thermostat to install most of the modern smart thermostat models.

Where do you connect the C wire?


Quote from Youtube video: For the common wire or. The ground path for the 24 volts to return to and so that is actually where we're going to go ahead and hook our C wire into underneath this wire nut.

What do I do if I dont have C wire?





Quote from the video:
Quote from Youtube video: Terminal. If there's already a wire attached to the C terminal. Just leave it be and attach a new wire next to it go ahead and push all the wires back into the wall. And close the backplate.

Where does the C wire get its power?

WHAT IS A C-WIRE? A C-wire, or a common wire, runs from your low voltage heating system (24v) and carries continuous power to your thermostat. In today’s electric market, most newer heating and cooling systems have C-wires, which guarantees compatibility for the installation of all smart thermostats.

Does C wire connect to air handler?

Older wires will have only 2 or 4 strands but the 5 strand will provide that extra wire known as the c wire. When connected inside the air handler, it provides that needed 24vac power for the smart thermostat.

How do you wire a C wire for a thermostat?

Quote from the video:
Quote from Youtube video: Run actual thermostat wire in the all and connect. It to the existing thermostat wire if you've got an extra wire or if you want to fish some new ones in the wall. Not a big deal there.

Where is the C wire on a thermostat?





Quote from the video:
Quote from Youtube video: But we're gonna go ahead and just pop the top off or pop the cover off your thermostat. Wherever you do that but mine has a little thing down here. And then we're have access to all the wiring.

Can I install Nest without C wire?

You can install a Nest Thermostat without a C-wire by using a C-wire adapter, that mimics a traditional C-Wire without you having to wire it. If you are not a handyman, it saves a lot of money that you would otherwise have to spend on a professional installer too.

How do I know if C wire is live?

Quote from the video:
Quote from Youtube video: Begin by putting one probe whichever probe you want on the rh wire and test every other wire with the other probe. One of the wires will show up is 24 volts and that is your c wire.

Do all thermostats require C wire?

There may be a few smart thermostat models that don’t require a C wire and can operate with batteries. You should always ensure proper wiring as needed for your HVAC system and corresponding thermostat (with or without a C wire).

Is the C wire just a ground?



C stands for common. The common wire is the ground or negative wire. To complete the circuit that provides power to the thermostat you need a positive and negative wire from the 24V transformer. Some thermostats have batteries that power them and they serve only as a switch to operate the heating or cooling unit.

Does C wire have voltage?

The C wire, a.k.a. the “common wire”, allows a constant flow of 24 VAC (volts AC) power to a smart thermostat. However, the C wire doesn’t provide the actual source of power to the thermostat. The wires that provide the source of power are the R wires (or hot wires).

Is C wire neutral?

The C wire is more like a neutral wire (in electrical terms) and it completes the electrical circuit between the furnace (or any heating system) and the thermostat, thus ensuring a flawless power supply to thermostat even when the furnace is OFF.

Can I connect three wires to the furnace C terminal?



If the terminals are allowed to have more than one wire, it will say so on the terminal block or in the manufacturer’s documentation. Two wires per terminal in HVAC work is common (though not usually correct), while 3 or more will tend to use a pigtail.

Is C-wire hot or neutral?

Typically, the wires that provide the power (often called the “hot” wires) are labeled Rc (cooling) and Rh (heating).

What color is C-wire on thermostat?

Blue wires

Blue wires are also called “C” wires because they are the Common wire. C wires are necessary for any “smart” thermostat that needs to be connected to a power source 24/7, regardless of your heat pump type.

Is RC the same as C wire?



Hi there! The C and Rc wires are not the same. To install this thermostat you should follow the exact same wiring of the previous thermostat.

What happens if you wire thermostat wrong?

Potential consequences of improper installation could include: Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself.