Is there a failsafe wiring for Vigirex RH99P residual current protection relay?


21 October 2021

Applicable ranges: RH10, RH21, RH68, RH86 and RH99M RH10, RH21, RH86 and RH99P

As you can see in the below description from the page A-11 of the Vigirex Catalogue, there are two methods of wiring;

1. Wiring for optimum safety (failsafe) - use of MN undervolatge coil in series with voltage presence contact 11-14 (catalogue page E-3)

In this scenario, you can see the MN is connected from the supply side and through 31-32 contacts (to maintain the connection when there is no fault) in series with the voltage presence contact 11-14 (which is closed when there is a supply to A1-A2). Therefore, as soon as the supply (A1-A2) is lost terminal 11-14 is opened losing the supply to MN coil. That will trigger the trip of the breaker.
In this way it will ensure the failsafe even if the auxiliary supply is lost to the relay.


2. Wiring for optimum continuity of service - use of MX shunt release
(catalogue page E-2)

In this method voltage presence contact is used only as an indicator and even if the auxiliary supply to A1-A2 is lost the connected breaker is not tripped as the MX coil is not powered (only powered if the relay detects a fault and will close 31-34).
In this way it will ensure the continuity of service, but not failsafe.



Vigirex Catalogue:

RHxxP Instructions Sheet: