Yes you can terminate any number of connections on the C terminal. All of the connections will be in parallel. This is very common.

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.

What does the C wire connect on furnace?





What is a C-Wire? A common wire (C-Wire) provides Wi-Fi thermostats continuous power by connecting it to a heating and cooling system (e.g. furnace). C-Wires are required on most Honeywell Wi-Fi thermostats, with the exception of the Smart Round Thermostat (formerly known as the Lyric Round).

What is the C terminal on the furnace?

The C wire, or “common wire” enables the continuous flow of 24 VAC power to the thermostat. Technically speaking, power flows from the R (red) wire, but not continuously (not on its own, anyway).

What is the purpose of the C terminal in a thermostat?

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 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).

Where do you connect the C wire on a furnace board?






Quote from Youtube video: The common terminal is going to be right here so if you're installing. Something you would stick the wire. Into this screw terminal from the bottom.

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).

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.

How do I bypass the C wire on my thermostat?

Quote from the video:
Quote from Youtube video: Add a jumper wire between the Y and G. Terminals. If there's already wires attached just leave them be go ahead and push all the wires in. And close the backplate.

How do you run a common wire on 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.

How do I know if my C wire is working?

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.

Can you use G wire for C wire?

If there is no hidden C-wire, you can use a G-wire instead. However, you will not be able to use your fan independently when the heating or cooling isn’t running. Also, many HVAC systems are incompatible with this solution, including: HVAC systems using electric heat.

Can I jump R to C wire?



C is a common neutral wire. You can’t jump it from Rh as that is a 24v wire. You need a third wire, C, to return to the unit and hook to the common side of the transformer. For ease of thought, think of R as “hot” and C as “ground”.

Is RC wire same as C wire?

No the Rc is the red wire. You need 5 wires or more for this to run with all the functions. You can use one of the other wires but you have to drop control of the fan. It will only come on when furnace comes on.

What color is the C wire?

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.

How do I know if C wire is live?



Easiest way to check is pull any batteries out of the old thermostat and look for a wire (normally blue) is connected to the C spot. If the old unit supports being powered by the common wire, then the unit will turn on without batteries.

What has C wire but no power?

Quick Check for an Existing C-wire:



If it has batteries, remove them. If the thermostat loses power it does not have a C-wire, and you may need an add-a-wire kit. If it doesn’t lose power, locate your breaker panel. Flip the breaker for the wall with the thermostat on it.

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.

Should R and C have continuity?

You’ll want to start by doing a continuity test on the R and C wires, to insure they are intact and not damaged. You’ll also want to do a continuity test on the secondary of the transformer, to insure it’s not damaged.

Can the C wire shock you?



The short answer is no, it’s not OK – you increased your risk of electrocution and that’s never a good thing specially for a DIYer.