NPUH800 and NPUH800R provide the monitoring of the homopolar voltage of 3-phase networks with an isolated or high impedance neutral. This multifunction relay monitors phase and earth faults, 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 NPUH800R to be used for quick replacement, by equivalence of function, of the relays in the relay CEE of the series 700 and 7000 (mechanical interchangeability.