Wattstopper ELCU-200 Emergency Lighting Cnotrol Unit Power Pack, 120/277 VAC, 50/60Hz, 754182923052. Wattstopper's ELCU-200 Emergency Lighting Control Unit is a self-contained device that allows any standard lighting control device to control emergency lighting in conjunction with normal lighting in any area within a building. Eliminates energy waste caused by emergency lighting that is always on; Integral push-to-test button activates emergency mode for a true test condition; Connects to EMTS-100 Remote Test Switch or other input to activate emergency on from a remote location; Operates as a control device or as a shunt; Senses local single circuit power failure; Zero cross switching technology for reliability and increased product life; Compatible with Wattstopper occupancy sensors, daylighting controls, lighting control panels, and dimmers