Plug-In Phase Coupler. Fits a standard (NEMA 10-30) 220VAC clothes dryer outlet. Boosts powerline signals by providing a bridge between the two, 120 VAC electrical phases (A and B) in a split-phase, 240 VAC home. Without a phase coupler, signals travel out to the street transformer on one phase and comeback in the home on the other phase; usually at a lower (attenuated) level. In homes up to 2000 Sq. Ft. and within 100 feet of the transformer, phase coupling may not be needed. As the size of the home and distance from the transformer increases, phase coupling becomes more important. A phase coupler is recommended in every main breaker panel and sub-panel to ensure maximum signal strength. The plug-in phase coupler is good for UPB, X10 and other higher frequency powerline signals. Simply Automated is an industry leader in home automation and lighting control. We provide an optimum solution for your home lighting automation needs -- most complete product line in the industry, powerful UPB powerline technology and low price. Simply Automated products utilize Universal Powerline Bus (UPB) technology. Our products work over the pre-existing electrical wiring in your home. No new wires needed! Powerful expansion capability -- up to 250 devices using UPStart software and your PC and Computer Interface Module (PN: UMC-USB). Add additional single rocker dimmers, deluxe dimmers with different faceplates (up to 8 buttons), lamp or appliance modules, tabletop pedestal with 8 buttons, wall receptacle, fixture relay, fixture dimmer or scheduler-timer. Lighting control for your entire home. To ensure a proper installation in your home: - Your home should be no more than 2500 square feet and have only one breaker panel. A phase coupler is required in some home installations. - Not intended for use in multi-dwelling (condo, apartment, duplex) units.