Help please rcd does not trip.

[ashdail]

Hi folks I have just installed an new mk consumer unit, but I'm having problem with the 63A rcd's. The test button works fine and it does not trip @ x1/2 it trips at 99.0 @ x1 and fails to trip @ x5 (>40ms) Its not the tester as I've checked it on another installation I know to be good. Any ideas? Help much appreciated.

 

[Deleted member 9648]

I'm surprised......I appear to be the only person on this forum who very rarly encounters faulty RCD's.

 

[Acer]

I have also been surprised by this especially as both incidents happened at the same location...the faulty rcbo is the first I have encountered but the MK rcd is a few years old and in a location which would leave it prone to dampness, dust etc...ideally the board should be an IP56 type enclosure but this would not be easy to achieve...however I do take on board the notion that the tester, once, calibrated may then be used without any further checks on its accuracy, apart from a check box and this would'nt help with the rcd function....?.