Power controlling relays (PCRs)

The live input to the X-ray unit is fed through the PCR, which is connected to the failsafe warning light. In the event of warning light failure, the PCR circuit opens, cutting the power supply to the X-ray unit.

A single PCR can be used with multiple failsafe warning lights, where there is more than one entrance to the controlled area.

This option is particularly suitable where general and dental X-ray units are located within the same controlled area. A selector switch should ideally be installed to switch the mains supply between the two X-ray units, with the live input to the selector switch fed through the PCR.