Sentrol Industrial INT-05-024 or INT-05-120 Expansion Safety Relay is intended for use as a part of a safety circuit. It provides three additional safe output contacts when used with the INT-03 Safety Monitoring Relay or INT-04 Emergency-Stop Safety Relay. The INT-05 uses positive-guided relays along with feedback contact to the INT-03 or INT-04 safety relay to prevent machine start-up in the event of a component failure. Voltage to the INT-05 is switched through the contacts of the INT-03 or INT-04. If a component failure occurs, the feedback loop to the INT-03 or INT-04 prevents machine restart.