Honeywell Thermostat Wiring For Ac February 24, 2019 What's a C. The C, or "common" wire can make -- or break -- your thermostat installation. Here's what you need to know. www.cnet.com Electric Dryer WiringDouble Pole Double Throw Switch WiringCeiling Fan Wire GaugeWiring A Switch With Light In Middle Of CircuitOne Way Lighting Circuit DiagramNo Ground Wire In Light Switch BoxHow To Wire Up A Toggle SwitchInstall Thermostat C Wire