Temperature - Controlled Cable Runs Straight Along Pipe And Valves, Held In Place By Application Tape And Plugs Into Grounded Electrical Outlet. Keeps Water Flowing To -40. Pipe Requires 1/2" Non-Flammable Insulation Such As Fiberglass. For Plastic Pipe, Its Recommended Wrapping Pipe With Aluminum Foil Before Cable Installation. The Traditional Resistance Cable Produces A Fixed Amount Of Heat Based On The Electrical Line Feed. It Comes With A Built-In Thermostat That Switches The Flow Of Electricity On And Off Based On Temperature. 120 Volts. 7 Watts Per Foot. CSA Listed.