The typical #18 AWG wire used for thermostat wiring is expected to handle a maximum of 2.3A (for power transmission). Thermostats for electric heaters run at 120VAC and have to handle the ampacity of the heating circuit.
How many amps can thermostat wire handle?
The thermostat wire is sized for mechanical durability, not for current carrying capacity. Codes may require the circuit to be Class 2, 30 volts and 100 VA maximum, usually 24 volts and no more than 4 amps. It could be much less than 4 amps and most of the capacity may be required for the relays in the HVAC unit.
Can I get shocked from thermostat wires?
Virtually all room thermostats operate on low voltage that carries little risk of harmful electric shock. However, it is always wise to shut off power to a thermostat at the service panel before examining or working on it.
Does the C wire carry current?
A C-wire, or a common wire, runs from your low voltage heating system (24v) and carries continuous power to your thermostat.
Do thermostat wires have power?
While some people think the C wire is what powers the thermostat, this isn’t entirely true. Typically, the “hot” wires, or the wires that provide power to the unit, are the heating and cooling wires, labeled Rc and Rh respectively. They provide the source of 24V power that comes into the main HVAC control board itself.
How much current can a thermostat handle?
Thermostats for electric heaters run at 120VAC and have to handle the ampacity of the heating circuit. Typically I see amperage ratings for these line voltage devices ranging from about 10.5A up to about 22A. For example a Broan 120VAC – 240VAC Model 87W line voltage thermostat handles 15 amps.
How much current does a thermostat use?
The thermostat wire isn’t sized for carrying capacity. The code requires the circuit to be Class 2, 30 volts and 100 VA maximum, with no more than 4 Amps. Most of the capacity may be required for the relays in the heating, ventilating, and air conditioning unit.
Is it safe to touch thermostat wires?
It’s “ok” in that if it works, you’re probably in the clear. However, there is a high risk of letting some of the thermostat wires in the bundle touch while doing this (the wrong ones) which would cause a short/surge back to the controller board.
How much voltage goes to a thermostat?
The most common type of voltage from a central heating and/or cooling system is 24 volts (24Vac). The old thermostat may say somewhere on the thermostat that it is for 24 volt (24Vac) or maximum 30 volts (30Vac). If you see 120 Vac or 240 Vac on the thermostat, a low voltage thermostat will NOT work with your system.
Do thermostat wires have voltage?
Quote from the video:
Quote from Youtube video: Going to each terminal. If you look at my wiring video that I have posted on my channel you'll see here this is our red this is our voltage 24 volts coming down to the thermostat.
Which wire in thermostat is power?
Thermostat Red Wire
Thermostat Red Wire (“R” or “Rc” Wire)
Red wire or “R” wire is the power wire. They originate in the transformer (air conditioners; in the air handler) and provide the 24-hour volt AC power. All air conditioner thermostats have a red wire for power.
How do you check voltage on thermostat wires?
Quote from the video:
Quote from Youtube video: The R and the G inside the thermostat to turn the fan on now I'm going to go ahead and turn the fan off and you see that our voltage has decreased. So what we're looking at is reading 24 volts.
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.
What is Y wire on thermostat?
Y – This is the terminal for cooling or air conditioning and goes to the compressor relay. Typically a thermostat wire pull is made to the air handler on split systems and then this wire is spliced for the separate wire pull which is made to the condenser.
What does W1 and W2 mean on a thermostat?
W/W1 and W2. In a conventional system, W/W1 controls your heating system and, where applicable, W2 controls your heating system’s second stage, which helps warm the home faster.
What are the 4 wires on a thermostat?
This is a popular configuration for a battery-powered thermostat or a digital thermostat that solely regulates heat. The standard configuration consists of 24-volt hot (red), 24-volt common (blue), heat (white), and a fan (green).
What color is 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.
What is the difference between RH and RC thermostat wires?
RC: The RC terminal is the 24-volt cooling power supply. RH: The RH terminal is the 24-volt heating power supply. (Note: The RC and RH terminals are jumpered together in a four-wire heat/cool system and a single-stage heat pump system but not in a five-wire heating/cooling system.)
What is a C wire for a thermostat?
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).
Is RC and C wire the same?
The C and Rc wires are not the same. To install this thermostat you should follow the exact same wiring of the previous thermostat.
Is com 24V the same as C wire?
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.
