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#1 Source in low voltage wire and cable. Call us today to learn more about special offers.
#1 Source in low voltage wire and cable. Call us today to learn more about special offers.

Thermostat Wire, Solid Copper, Indoor/Outdoor Sun Resistant, Brown

SKU: TC-2008/182
Size & Conductor
UL Listed


Thermostat Wire, 18/2C through 18/8C, 250 ft. and 500 ft.

Our Thermostat Wire is a Class 2, power-limited circuit cable, manufactured for use in thermostat control applications that are commercial and/or residential, highly comparable to both Honeywell and Southwire. Thermostat Wire is often utilized for low voltage applications, such as thermostat controls or HVAC equipment. The identifiable riser-rated brown jacket both resists moisture and repels harsh UV rays from the sun, furthering the overall capabilities of this product when implemented within both indoor/outdoor sites. Moreover, the conductors inside are color-coded to meet specific and established functions.

Thermostat Wire to Fit Your Application

When regarding the variations of Thermostat Wire offered, keep in mind that not all thermostats are alike. More traditional thermostats may require five strands or less; however, smart thermostats, such as Nest thermostats, being implemented within both residential and commercial areas, demand additional modes of accessing and directing electrical currents, what is known as common wire (or c-wire), in order to function properly. That is one of the reasons we offer our Thermostat Wire at higher strand counts, which include c-wire(s) within them, along with standardized strand counts as well; we want to provide options fit to accommodate all applications through a high quality product that will remain unfailing and abiding for years to come.

Thermostat Wire Installation

Our Thermostat Wire can easily be cut and molded to adhere to your designated application space. Remain educated as you go through the installation process; ensure that you have the necessary tools to get the most out of your Thermostat Wire. Browse our selection of Wire Cutters and Strippers and choose from a wide array of hardware designed to meet your needs. We pride ourselves on offering an end-to-end solution, striving, above all, to provide satisfaction for our customers.

Thermostat Wire Applications



  • 150 Voltage Rating
  • UL Listed
  • Sun Resistant
  • Solid Bare Copper
  • Thermostat Control
  • Heating and A/C installations
  • Touch-plate systems
  • Burglar alarms
  • Intercoms
  • Door bells
  • Annunciator systems
  • Remote controls
  • Signal systems
  • Low-voltage installations
  • Withstands -20 ºC to 60 ºC (-4ºF to 140ºF)



Gauge/Conductor Count Conductor Colors Spool Dimensions
18/3C Red, White, Green 4.8" x 6.25"
18/4C Red, White, Green, Blue 4.8" x 6.25"
18/5C Red, White, Green, Blue, Yellow 5.2" x 6.25"
18/6C Red, White, Green, Blue, Yellow, Brown 6.5" x 6.25"
18/8C Red, White, Green, Blue, Yellow, Brown, Orange, Black 6.5" x 6.25"

Additional Information

Color Coded Thermostat Wire Chart for Standard Applications

Based on industry standards and general applications, here are a few of the commonly recognized color codes in association to the wires found within Thermostat Wire. Please note that not all thermostats are manufactured and maintained the exact same way. Therefore, it is important to regard this chart as comprehensive information based.

Red R – 24V Power | Rc – 24V Cooling | Rh – 24V Heating
White Core Heating
Yellow Core Cooling / Air Conditioning / Compressor
Brown Emergency Heat
Green Fan
Orange Heat Pump
Blue Common Wire
Black Common Wire

What's in the box?

What's in the box?

  • Qty 1 - Spool of Thermostat Wire, Solid Copper, Indoor/Outdoor Sun Resistant, Brown