In article ,
John Rumm writes:
On 15/12/2012 14:59, Caecilius wrote:
I've been experiencing occasional nuisance RCD tripping for a few
years now. It's very occasional - sometimes going for up to six months
without tripping. On average I'm getting a trip around once every two
months.

I've done some equipment testing with a megger and basic RCD
sensitivity testing with some home-made leakage plugs (plugs with
resistors between live and earth to give a known leakage current).
Based on this, I think my RCD is over sensitive.

My plan is to replace the RCD, which is fairly cheap and simple. But
I'd like to test the old one and the new one with something better
than leakage plugs to see if there's any change in sensitivity.

A RCD tester won't do much more than your improvised equipment will do
in terms of things you are interested in (i.e. trip thresholds, rather
than response times).

I still use the one I made 20 years ago, with a 5mA, 10mA, 15ma, 30mA
switch. If I was making it today, I would also include a couple of
diodes and switches to do the pulsed DC test.

I've never found an RCD which failed by taking too long to trip.
Only those that are too sensitive, or don't trip at all.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]