I have a garage CU (mains incomer) supplied from the the house CU through a 32A MCB on a non-RCD protected circuit. I noticed that the garage unit RCD was not tripping during a fault state, be that with a short form L to N or Earth...what happens is that the garage unit and the house unit MCBs trip together...the "test" button on the RCD trips it as expected. The unit is a GET GIC240R 40A...2 circuit (16A and 6A) with a 30mA sensitive DP RCD.
Many thanks.
Many thanks.