Nest thermostats are designed to use very little power, and in many cases they can use your system’s heating and cooling wires to get enough consistent power. But sometimes, you may need to connect a common wire (C wire) or power accessory, like the Nest Power Connector, to make your system compatible.

Where does C wire go on Nest thermostat?

Quote from the video:
Quote from Youtube video: And we're going to use it as AC wire the common wire and what a common wire does is it allows a return current path from the power the are see through the thermostat. And back through the C wire.

What happens if Nest doesn’t have C wire?





Quote from the video:
Quote from Youtube video: And today I would like to talk a little bit about nest thermostat wiring and more specifically the C or the common wire is it really needed on the nest or not according to nest. Themselves. They say

Can you install Nest without C wire?

Quote from the video:
Quote from Youtube video: It is recommending that we add a c wire here it says the thermostat will work with your system but we recommend adding a c wire to avoid. Potential power issues in the future. Now when installing the

What color wire goes to the C on Nest?

General Thermostat Wiring Color Code

Terminal Wire Color
C Blue/Black
O/B Orange/Dark Blue
E Any Color
X Any Color

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.

Can I 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.

How do I install a smart thermostat without C wire?

Quote from the video:
Quote from Youtube video: The screws and anchors and the thermostat. We're gonna need a set a screwdriver or a drill. And if you don't have a CE wire. We're gonna use a C wire adapter.

Can you run a Nest thermostat without a common wire?

These wires get the power from your heating system, cooling system, or your furnace, and make sure that your thermostat doesn’t need to be recharged. According to the Nest website, your Nest thermostat will work without a C-wire but specialists still recommend using an adapter if you can’t get a C-wire installed.

How many wires do I need for a Nest thermostat?



How Many Wires Does Nest Learning Thermostat Need? Typically, four. This is parallel to the standard four wires that most standard thermostats use.

Is RC and C wire the same?

Typically, the wires that provide the power (often called the “hot” wires) are labeled Rc (cooling) and Rh (heating). They provide a source of 24V power coming from the HVAC control board. Sometimes they are separate wires and require separate connections. Other times they are the same wire.

What does C stand for on Nest?

Nest thermostats are designed to use very little power, and in many cases they can use your system’s heating and cooling wires to get enough consistent power. But sometimes, you may need to connect a common wire (C wire) or power accessory, like the Nest Power Connector, to make your system compatible.

What do the different color wires mean on a thermostat?



This is the most typical thermostat wiring style, and it applies to systems that regulate both heat and air conditioning. The wires are typically arranged as follows: red for 24-volt hot, white for heat, yellow for cooling, green for the fan, and blue for common (although the common wire may be a different color).

How do you run a C 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.

How do you identify C wire?

Quote from the video:
Quote from Youtube video: So it's fairly simple to tell if you have a/c wire or not firstly the purpose of a/c wire is basically for the newer thermostats. As either has a backlit display or has Wi-Fi functionality.

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.

Does C wire have voltage?



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.

Why does my Nest not have power?

A “No power” alert can be caused by the following: The thermostat wiring is incorrect. Your thermostat is connected to a system that requires a C or common wire, but that wire isn’t connected. Some systems, including heat-only, cool-only, zone-controlled, and heat pump systems, require a C wire or Nest Power Connector.

Why does my Nest say no power to Rh wire?

Quote from the video:
Quote from Youtube video: And it's caused by the float switch on the air handler detecting that the condensation. Isn't draining out of the lines. So what it does is it cuts power to the thermostat.

Should Nest be connected to RC or RH?

Important: Always follow the wiring diagram the Nest app gives you during setup to connect your Nest thermostat. Here are some general guidelines: An R wire can go into a Nest Learning Thermostat’s Rc or Rh connector. The Nest Thermostat E only has an R connector, which is typically where an R wire would go.

Are R and RH wires the same?



R , Rh , and Rc are all the same, but not. In general terms, the R terminal is where you connect the signal voltage source. In low voltage controlled systems, there will be a step down transformer that provides the power to the control circuitry.