- Reaction score
- 10,616
2 RCDs in the same circuit is only a problem if tripping of the origin one will be a
nuisance. So it depends what other circuits are on the CU RCD.
Doing away with the RCD at the garage does nothing to help.
You can acheive discrimination if the CU RCD is higher opertaing current and/ or faster.
When I had a similar problem I tested a variety of 30mA RCDs to find a make that would discriminate on speed. I found Hager would always react faster than the existing RCD which was Merlin if my memory serves.
Not sure that's an approved way of obtaining discrimination between RCD's, at least as suggested by manufacturers.