Table of Contents
Thermostat Wire - Thermostat wire comes in a bundle with the outer jacket being either brown or white. The bundle can have anywhere from 2 conductors inside the bundle or outer jacket and all the way up 8 or 10 conductors inside the outer brown or white jacket. The bundle for typical wire is 18 gauge solid copper conductors and each has its own outer jacket that is a different color than any of the other conductors in the bundle. These multi-color wires are colored differently for identification from one end of the bundle to the other end of the bundle. It can be purchased in a bundle as follows:
All About Thermostat Wire - HVAC Control
- 18-2 - 18 gauge solid copper - two wires in the bundle - red and white colors with brown/white jacket
- 18-4 - 18 gauge solid copper - four wires in the bundle - various colors with brown/white jacket
- 18-5 - 18 gauge solid copper - five wires in the bundle - various colors with brown/white jacket
- 18-6 - 18 gauge solid copper - six wires in the bundle - various colors with brown/white jacket
- 18-8 - 18 gauge solid copper - eight wires in the bundle - various colors with brown/white jacket
The above list represents the most common combinations of wires available for air conditioning and heating wires. Other combinations of wire may be available. Wiring a new thermostat is made simple with our handy instructions for thermostat wiring color codes. See the menu to the right for the page.
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. Using a solid conductor ensures a hair from a strand will not cause problems.
Why does the outer jacket make a difference? It does not make a difference unless the wire is run in a plenum. Inside a plenum or a place where the air will be used for the air inside the structure.
18 Gauge Wiring Bundle in an Outer Brown Jacket
Thermostat Wiring and the Code
This is an NFPA Code (National Fire Protection Association). The code requires any wire run in a plenum is required to be plenum rated. This refers to the outer jacket and what happens to the outer jacket if it catches fire.
Plenum-rated wire has an outer jacket that is not toxic when exposed to heat or flames. Plenum-rated thermostat wire increases the chances of people surviving a fire if the structure has a fire in the future. If the conductors are run inside the wall then there are no codes about using any special wire. That is as long as the wire is inside the walls and not exposed to conditioned air or spaces.
All About Thermostat Wire
COVID 19 Home Protection
UVC Light to Kill Viruses and Other Airborne Harmful Things that Affect Health
For additional protection you can also use a UV Light that will kill harmful viruses and bacteria inside the airflow of the air handler. In labs researchers used a spectrum of ultraviolet light called UVC to kill viruses. This product requires professional installation so it will turn on and off with the blower fan in your air handler but it will offer the protection you need for you and your family from any viruses.
Click the image to the right for purchase options of the UV light to protect your family.
