HAI recommends that every HAI Lighting Control (HLC) installation include this part.
HLC is for single phase 120/240 VAC, 60 Hz systems. The HLC Phase Coupler mounts by the circuit breaker box and is used to connect the signal from L1 to L2 within the circuit breaker box.
Although HLC is extremely robust and less susceptible to powerline conditions, HAI recommends the use of a Powerline Phase Coupler in every HLC installation.
Diagram
LED
The LED on the Phase Coupler shows that it is working.
Although HLC is extremely robust and less susceptible to powerline conditions, HAI recommends the use of a Powerline Phase Coupler in every HLC installation. 
