Coleman Cable 55303 Thermostat Wire, CL2 Solid Bare Copper, 18/3, 500-Feet. 500-Feet spool of wire. Thermostat Wire, CL2 Solid Bare Copper, AWG size: 18/3. Smooth jacket eliminates snagging and tearing. Some applications: thermostats, air-conditioning controls. Pvc jacket, polypropylene insulation ensures excellent strip ability . Some Applications: Thermostats, air-conditioning controls. common uses in low voltage remote control circuits, doorbells, alarm systems. 18/3 CL2 BAROSTAT 500. The Coleman Cable brand is a registered trademark of Coleman Cable Inc.