RCD Fault (I'm baffled)

[R46yam]

Hi there all, many apologies as I'm new to testing so am still trying to get head around everything.

Testing an RCD today with all MCB's off I had some unusual readings which have confused me somewhat. The RCD was a Contactum 80A Type A. I was using a Kewtech KT64 and below are what it returned.

x 1/2 0 = >2000ms
x 1/2 180 = >2000ms
x 1 0 = >550ms
x 1 180 = >550ms
x 5 0 = 13ms
x 5 180 = 7ms

Doing a ramped test the tester returned a reading of >33mA

What would cause it not to trip on a x1 test yet it trips quick enough on a x5 test. I can appreciate I have missed something but what should I be looking for?

Many Thanks

 

[Deleted member 72666]

Faulty RCD, end of!

 

[Deleted member 72666]

.... and probably due to it not been regularly tested by the consumer/occupier!

 

[R46yam]

Thanks for the quick reply, I thought the same thing and rang TLC (where I bought the RCD) they seemed quite sure that this was not the case. Is there any other possible reason or is that the only thing it could be?

 

[telectrix]

yep. as above. it's tripping at > 33mA on ramp test, so it will show "out of limits" on x1. try the test button a time or 2, then retest. if still poor readings, replace it.

 

[R46yam]

It was a brand new RCD, I switched it on and off a couple of times as well as hitting the test button a few times and this was still the reading after all that. I will be on to TLC first thing, really grateful for everyones help.

 

[telectrix]

one other thing to try is to remove both L and N from the outgoing side and test the RCD directly. sometimes there is something on the circuit/s will give you false readings. otherwise, it's fooked.

 

[Octopus]

one other thing to try is to remove both L and N from the outgoing side and test the RCD directly. sometimes there is something on the circuit/s will give you false readings. otherwise, it's fooked.

defo the test to do before running back to TLC. Make sure all the MCB's are off

 

[tony mc]

Its not a 100mA RCD by any chance is it ? And your testing it on the 30Ma scale !

 

[lewlec]

Hi
Maybe it's something to do with it being a type A rcd?

Regards
Gary

 

[Deleted member 72666]

Its not a 100mA RCD by any chance is it ? And your testing it on the 30Ma scale !

Highly unlikely to be a 100mA rcd as it ramps at 33mA!

 

[Landril]

How long you had the tester and has it been in for calibration at all?

More than likely though it is a faulty RCD.

 

[Engineer54]

Thanks for the quick reply, I thought the same thing and rang TLC (where I bought the RCD) they seemed quite sure that this was not the case. Is there any other possible reason or is that the only thing it could be?

What the hell would they know?? They are in the business of selling, not assessing. And they don't particularly like returns either!! Not when they can be avoided!! lol!!

 

[bigbaddave]

This thread was over at post 2.... Lol

 

[telectrix]

true, but it passes the time when work is slack.