Hardwired to circuit breaker or main disconnect, Model UPA-130 reduces risk of electrical arc flash by preverifying electrical isolation from outside of control panel. Redundant circuitry allows it to be powered by same voltage it indicates. NEMA 4x, IP66-rated, 8-detector power alert fits 30 mm knockout. It visually alerts operators to presence of any dangerous ac or dc potentials occurring between any combinations of 4 input lines.