Leviton HCA02-10E 120/240-Volt 1 Phase, DHC System-Amplifier/Coupler/Repeater, Black System Amplifier recommended for all DHC installations to ensure adequate command signal strength Panel-Mounted Surge Protective Device recommended for all DHC installations to protect DHC circuitry from damaging high-energy transient voltage surges Should be installed on the main panel on its own dedicated 15A breaker CANNOT be used in a 3-Phase System use 6201 Part of Leviton's award winning residential system