RCD trip current and nuisance tripping

[lumphammer]

I have a Moeller 30mA 61008 RCD that trips out randomly sometimes immediately sometimes after a few days.

It passes the 50% rated current test, but a ramp test shows it ripping at 21mA, this seems low to me, is this right?

 

[ricicle]

Did you test it with all other circuits disconnected as leakage currents might have contributed to the early trip - however 30mA RCDs will trip before their rated trip current anyway.

Have you tested the installation?

 

[Lectrician]

I dont know why people insist on ramp testing...perhaps because it is easier than finding the underlining cause............get your instrument set to insulation resistance and find the true cause!

21mA is actually fairly typical for 30mA device.

Why do people always jump on the bandwagon saying 5ma+5ma+10ma+another 10.......

This is hardly ever the actual cause! Extremely rare! And if this is the cause, then it is a very poor installation with far too many circuits on an RCD.

It is predominantly a faulty item or part of a circuit that is the cause - even if it appears to be caused by turning on certain items.

I hate seeing people say "well if you have 5mA here, and 5mA there.....".

In all my time fault finding, I have never come across this as a cause for a call out to nuisance tripping. And I get ALOT.

 

[reggie perrin]

Blimey.