Fault Finding Query

[JackTheCat]

Fellas,
Still learning my way regarding fault finding, wondering if anybody can see any flaws or would they do it a different way with a slight problem today.

Split load board, 3 ring mains and a shower on RCD side, its a clipsall CU and i noted it was a terrible install.

RCD trips out about 5 times a day, the lady said it could be any appliance at all that trips it.

I isolated the ringmains and turned one on at a time checking each appliance as i went along, everything was fine on all the ring mains and shower.

I then plugged rcd tester in 1 ringmain and applied half the current, it tripped.
I then turned this ringmain off and did the same test on another ringmain and it tripped at half the current.

I then went to board, (test button on rcd was a bit dodgy) and applied the 3probes to load side of rcd, tripped out at half the current, im assuming its a faulty rcd (button was knackered anyway so needs replacing regardless)

Any advice appreciated?

 

[Spark123]

As a final test I would try testing the RCD on its own without anything else connected to eliminate a possible fault on the circuits, if it still trips at 0.5I it is definitely dodgy.

 

[JackTheCat]

Spark123
I should have said, yes i did that test on RCD, thanks for reply

 

[redmile]

rcd might be up the duff? try a new one.