Typically, the wires that give the power supply (usually termed as the ‘hot' wires) are marked Rc (for cooling) and Rh (for heating). They give a 24-volt power supply from the HVAC system's control panel. ‘ If your system has a
common wire, it will be marked ‘C' at most times
.
What color is the C wire?
The
blue wire
on the thermostat is the Common or “C” wire.
What if there is no C wire for thermostat?
If you don't see a wire you can identify as the C-wire, though, don't despair yet – you may need to look behind your existing thermostat. If your current thermostat didn't need a C-wire, it (or a wire that can be used as a C-wire) might
be rolled up inside the wall
.
How do I know which wire is the C wire?
It is easy to see if you already have a c-wire connected to your system.
Simply remove your current thermostat face from its baseplate and look for the terminal labeled with the letter “c
.” If this terminal has a wire attached to it, you have an active “c-wire.”
What is RC wire on thermostat?
Red or “Rc” Wires
Red wires, specifically Rc wires, are
responsible for 24-hour volt AC power from your transformer
. Rc wires are only for air conditioning systems or dual transformer systems. … These wires only connect to your cooling system. Rc wires connect to the RC terminals on your thermostat.
Does R go to RC or RH?
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. … These are not jumper wires, and you can insert the Rc wire into the Rc connector and the Rh wire into the Rh connector.
Why is there a jumper between R and RC?
Effectively there isn't a second RH wire, although there is an RH terminal. However,
the heating still needs to be controlled
, so a wire known as a jumper is connected between the RC and the RH terminals so that power gets to the heating control part of the thermostat. This wire is also known as the RH wire.
Does C wire have voltage?
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.
Why is my C wire Brown?
A brown wire is mostly likely a
heat pump wire
and should be connected to the O/B connector on the Nest thermostat. If the B wire is blue, it should most likely be connected to the C connector.
Is the C wire Green?
G wire (
green
, for a fan). Y wire (yellow, for air conditioning). W wire (white, for heat). C wire (blue or black, common for 24-volt power to the thermostat).
Can I use the G wire for the 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.
What happens if you wire thermostat wrong?
Potential consequences of improper installation could include:
Electric shock
. … Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself.
Can you install nest without C wire?
Nest thermostats are designed to work without
a C wire in most homes. But some systems may require a C wire for consistent power. The Nest Power Connector is a simple and affordable alternative to a C wire, and costs much less than hiring an electrician to install a new C wire through your walls.
What color is the common wire?
The
White
is often referred to as Common, but the colored wires are also used as hot wires.
What is the common wire on 3 way switch?
Black wire
: This is a hot wire that carries electricity from the power source to the first switch in a typical 3-way setup. It's also called the “common wire” or the “line wire.” Unless the breaker is off, this black wire is always hot.
What is C wire on nest?
The c wire is an extra wire that
can be used to provide a return path for continuous 24V power for any application
. It's normally used to provide a return path to power the thermostat. The “c” stands for common. It is often labeled as “c” on thermostat backplates.
