The most common thermostat cabling is 18/5 (18 gauge, 5 conductor), because 5 conductors typically offer enough functions for a modern thermostat/low voltage device.
Are all thermostat wires the same?
The wires are all the same: solid copper wire covered with colored PVC insulation. The color code was started to make jobs like you’re tackling easier. Here’s how to wire a thermostat using the color code and, FYI, each terminal’s purpose. Attach the red wire to the R terminal (Call for heating and/or cooling).
What class is thermostat wire?
Class 2
A Class 2 power-limited cable for use in thermostat controls applications, bell and alarm systems, not to exceed 150 volts when installed as specified by the National Electrical Code® (NEC) and other applicable standards. Thermostat wire is sunlight resistant.
Can you use 22 gauge wire for a thermostat?
Nest thermostats require wires between 18 and 22 gauge, which is standard for residential heating and cooling systems. Anything smaller than 22-gauge wire could be too thin for a Nest thermostat to detect.
What color is the C wire on a thermostat?
blue wire
The blue wire on the thermostat is the Common or C wire.
How do I know what wire to get for my thermostat?
Look for connectors that have labels that are the same as your thermostat. For instance, you might find labels like R, W, G, Y, C or O/B. You should find wires attached to these connectors that are the same color as the wires that connect to your thermostat.
Can you use cat6 wire for thermostat?
Ethernet cable should work fine since thermostats use low voltage and low current. For simplicity, it’s probably easier to use each pair as if it were a single wire.
How many wires does a thermostat need?
The most basic thermostat has 2 wires; usually a red and a white wire. Two wire thermostat wiring is used for furnaces only and usually doesn’t need a C or Common wire. That’s why we only need two wires: Red wire for power (24h).
What is a 18 gauge wire?
AWG stands for American wire gauge. It relates to the diameter of the wire. The more current capacity it can carry, the lower the AWG. A thicker 16AWG can carry 13 Amps, but a thinner 18AWG can only carry 10 Amps.
Can telephone wire be used for a thermostat?
Phone wire would probably work fine in most millivolt situations, but some thermostat wire has decent current going through it (like 24V control loops), so – as always – why not use the right stuff. It might leak more current and not complete the circuit in long runs….the lighter wire, that is.
Does thermostat wire need to be solid?
All About Thermostat Wire – Composition
Solid copper is recommended for use in HVAC applications. Stranded copper wire leaves open the possibility that a hair (part of a strand in a stranded bundle) can cause serious problems. Stranded conductors increase the possibility a malfunction can occur in the system.
How many amps can 18 gauge wire take?
16 Amps
A conservative estimate for several feet of 18 gauge wire is 16 Amps. If you have only 12 gauge wire, the 18 gauge wire can handle more than 16 Amps.
What color is b wire on thermostat?
Blue
Thermostat Wiring Color Code Chart
| Marking | Wire Color Code | Description |
|---|---|---|
| Y2 | Yellow | Secondary cool call relay |
| G | Green | Fan relay |
| O | Orange | Change-over relay to cool relay |
| B | Blue | Change-over relay to heat relay |
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.
What is b wire on thermostat?
O, B, O/B: These wires are responsible for switching the changeover valve in a heat pump system. The O wire reverses the valve from heating to cooling, and the B wire switches the valve from cooling to heating.
What are the 4 wires on a thermostat?
In general, the heating wire (often white), goes into the W port, the cooling wire (often yellow), goes into the Y port, the wire that sends power from the HVAC system to the thermostat (often red), goes into the R port, the fan wire (often green), goes into the G port, and the common wire (often blue), which
Is C wire the same as RC wire?
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 Blue C wire on a thermostat?
The Blue or C Wire
C wires or varying colors apply to every thermostat, but blue C wires belong to thermostats attached to a heat pump. Blue wires are for heat pumps. This wire connects to terminal B on your thermostat.
Can I use CAT 5 wire for thermostat?
Cat5 is used for thermostat wiring. If you’re running a wire that’s bigger than you need, a lot of the new thermostats control humidifiers and other components. The cat5 is likely to work doubled up as it is.
Can I use speaker wire for thermostat?
Aside from use as a power cord, you might consider running speaker wire through your walls in low-voltage applications, such as thermostats, sensors and hard-wired smart-home devices.If you want to run the wire through a heat duct, you’ll need wire with the CL2P or CL3P rating.
What size wire is in Cat 5?
24-gauge
CAT5 is currently the industry standard for network and telephone wiring. CAT5 contains four pairs of 24-gauge copper wiring and ends in a standard RJ-45 jack. This type of copper wire cabling is known as twisted pair cabling and is only recommended for a maximum distance of 100 meters or 328 feet.
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