NPIH(D)800 and NPIH(D)800R ensure the detection of homopolar currents in medium and high voltage electricity networks. These digital and multifunction and directional (D) relays monitor faults between phase and earth, and also the proper functioning of the circuit breaker and its triggering circuit.

These functions associated with an R type modular unit, thus allow the NPIH(D)800R to be used for quick replacement, by equivalence of function, of the relays of the CEE relays of the 700 and 7000 series (mechanical interchangeability)