The Warm Tiles Relay Kit allows you to connect two or more floor warming kits in the same room. First you would connect the first line voltage feed to the thermostat. The load connection pigtails from the thermostat are run to the coil of the relay, which is housed in a separate electrical box. A second line voltage feed is connected to the input terminals of the relay and the heating cable cold leads are connected to the output terminals. When the thermostat calls for heat, the coil is engaged, connecting the input and output terminals, therefore allowing power to flow to the cables. Remember to follow the detailed instructions provided in each Relay.