Models 258 and 269 continuously monitor three-phase power lines for phase loss, phase reversal, and low voltage. Model 269 also monitors for high voltage. Models 258 and 269 do not require a neutral connection and can be used with any Wye or Delta systems. When correct voltage and phase rotation are applied, the internal relay will energize. A fault condition will de-energize the relay. When the fault is corrected, the monitor will automatically reset.