Eaton RCD/MCD - PKNM Series Introducing Eaton's range of PKNM RCD's, a professional and high-quality range of residual current devices. Providing complete protection, these RCD's have been created and designed to protect users from a fatal electric shock through the use of the automatic switch-off of electricity where there is a fault. The device monitors the in going and outgoing current flow and trips when an imbalance occurs. These RCD's are commonly installed in applications where there are exposed wires, prone to overheating or earth faults. Each device from the PKNM range incorporates a red and green contact position indicator. The range also features a 3 position DIN clip which is to help prevent the removal of the appliance.