PIR via a Contactor Large Load - Wiring Diagram Part 4 Matt looks at the basic wiring diagram for a circuit controlled by a Passive infrared sensor (PIR) switching a contactor controlling a large load heavy load). He looks at the working principles for controlling a circuit by a remote PIR to control things such as lights. In part one Matt looks at the wiring connections in both the PIR's and the use of a contactor to switch the load circuit is via two circuit breakers (CB) This On Site with Mat