Yes, you can use the blue wire the way you have described. Instead of all of that work to attach an extension to the blue wire, I would just cut back some of the brown sheath. That’s assuming that there is enough slack in the cable for that to work.

What does the Blue wire connect to in the furnace?

Blue wires are for heat pumps, like orange wires. This wire connects to terminal B on your thermostat.

Do I need to connect the Blue wire on my thermostat?





The Blue or C Wire



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 extend my thermostat wires?

Quote from the video:
Quote from Youtube video: The first step just cut this out. When you're stripping back thermostat wire. This is just typical 18:8 South wires number set wire and when you're stripping it back I want you to snip into the end.

Why does my thermostat have a Blue wire?

The blue wire, or C-wire, is known as the common wire. It’s there to provide power to the thermostat. Older thermostats usually don’t have a C-wire because they either don’t need power or, if they do, they get it from a battery.

Where does the Blue wire go on my Nest thermostat?

If your thermostat doesn’t have a separate connector labeled C and you’re not sure what type of system you have:

  1. A brown wire is mostly likely a heat pump wire and should be connected to the O/B connector on the Nest thermostat.
  2. If the B wire is blue, it should most likely be connected to the C connector.





Where does the Blue wire go?

The blue wire from the ceiling fan gets connected to the second live wire from the ceiling. This second wire can vary in color but is most commonly red or black. This connection allows you to power your lights from the second switch.

Can you run a Nest thermostat without a common 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.

Is G wire necessary?

As you mentioned, you don’t usually need a G wire for heating mode, but you do for cooling. In special circumstances a relay could be wired up inside of the air handler to make the fan come on with a call for cooling, but normally it’s the thermostat that makes the connection that makes the fan come in in cooling mode.

How do I connect the wires to my Nest thermostat?



You’ll get a custom wiring diagram for your system after you’ve installed the thermostat base.

  1. Switch off power to your system. …
  2. Remove your thermostat’s cover and take a picture. …
  3. Get a wiring diagram from the app. …
  4. Remove jumper wires and save them. …
  5. Label the wires. …
  6. Disconnect the wires. …
  7. Mark where screws will.

What do furnace wire colors mean?

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). You can also refer to the Conductor Color Chart (see Chart 6, thermostat wire).

What color wires go on a Nest thermostat?

To wire up your Nest Thermostat, simply: Connect the Red wire from the transformer to either the Rc or Rh terminals (as they are connected internally) Run the White Wire from the furnace to the W terminal. Connect the Yellow Wire from the compressor to the Y Terminal.

What is a common wire for Nest thermostat?



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. Unlike other wires connected to your thermostat, a C wire doesn’t control heating or cooling functions. It only provides constant power to your thermostat.

What happens if you wire a 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.

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.

Can I use a Nest Thermostat with only 2 wires?

The Nest Thermostat is compatible with 2 wire low voltage HVAC systems that are either heat only systems or cooling only systems.

Can I use G wire for C-wire?



Option #3: Use a G-Wire as a 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 wire a 2 wire thermostat to my furnace?

Quote from the video:
Quote from Youtube video: It has constant voltage and when the thermostat demands Heat it bridges and gives power to the white which then feeds up to the heating element in the in the heating duct.

What happens if you wire a 2 wire thermostat wrong?

If you get it wrong, the heat will run continuously. Once you have them paired, attach one pair to “24VAC” (R) and the other to “Heat call” (W) on the thermostat. Doesn’t matter which one, since the thermostat just shorts them either way.