I installed this Aube Technologies RC840T-240 Electric Heat Relay with an Emerson Sensi Smart Wi-Fi Thermostat controlling Enerjoy radiant heating panels in the main living area of our home. Aube relays in a metal junction box just below the main electrical panel in my garage. For the 24V wiring, I connected the Sensi thermostat to the Aube relay using a 18-5 thermostat wire as follows: Blue wire: Aube C terminal to C SensiRed wire terminal: Aube R terminal to right wire SensiWhite -Wiring: Aube W terminal to W/terminal E Sensi For 240 volt wiring: Using a 12-2 Romex, I painted the white wire red with a marker (this is my usual method for 240 volt wiring, which doesn't use a 120 volt application required). -out wire Aube c red wire connected to line out red wire The system works as I hoped it would and it's great to be able to control the heating panels remotely and have all the smart thermostat features. I installed Enerjoy panels 25 years ago and over those 25 years they have proven to be a very efficient and maintenance free heating system and I am very happy that I can now control them remotely when travelling.