• Custom microprocessor controlled for highest accuracy and reliability. • 3 LEDs for checking correct wiring status. • 0 and 180 degree phase angle switch permits quick tests and consistent readings. • Digital read-out of tripping time. • Constant current source circuitry ensures that a fluctuating mains voltage does not affect the accuracy of readings. • Large custom digital display readout. • Visual indication of reversed phase and neutral wiring at socket. • Designed to IP54 Rating. • Complies with IEC 61557 • Test of a large kind of RCD's: Standard, Selective, AC and A (DC sensitive breakers)