Can i use Vigirex residual current relays for 3-wires systems with no distributed neutral?

The Vigirex residual current relays, combined with a toroid, provide protection against earth leakage currents for all LV electrical network types less than 1000 V, regardless of the type of earthing system (IT, TT or TNS). They protect equipment and people against direct and indirect contact, and equipment against fire hazards. You can use them with 4-wires and 5-wires systems. We also have specific Vigirex relays suitable for motors (3-wires systems).

For 3-wires systems with no distributed neutral, you can use Vigirex relay RH99 for Motor Protection. For this range of Vigirex relays, it is sufficient for the 3 phases to pass through the toroid.
Note: The PE should be avoided in the Toroid.

The operation principle of the Vigirex relay can be found on page E-14 of the Vigirex 2016 catalogue. The Vigirex 2016 catalogue is attached.

Released for:Schneider Electric United Arab Emirates