Cannot get RCD test to work?

[Meggerman]

Have triple checked polarity (as I was tired!), Zs is ok and I proved the meter on another RCD in the same house.

Do you have ramp test facility on your MFT? If you do then set it to the highest range and test.

 

[spark 68]

If the Zs is 0.9 then I don't see the touch voltage being set @ 25V being the problem, I would check the continuity of the CPC all the way through the circuit though.

I would also try the test at the outgoing terminals of the RCD with the outgoing circuit disconnected first too, to narrow down where the problem may lie, it maybe simply that the RCD is faulty.

 

[trev]

Not when the OP has said this it isn't
"I make contact with the live/neutral/earth of something which the RCD is feeding, I get the little "

Which implies that he has not tested at the load terminals of the device. You test the device not the circuit

 

[GLENNSPARK]

well i`v had them (RCD FCUs) faulty straight out of the box....

most of them are a bit crappy to be frank with you...

 

[HappyHippyDad]

What tester is it .

What exactly does it say on the screen ?

Sorry Jackhammer, missed your reply.

Its a Metrel MI3000 and I'm embarrassed to say I did not make a mental note of the error display.

 

[R G]

I too think the device is being tested on the input side ,as Trev says , also don't forget to isolate the outgoing circuit if pos to avoid false readings ,,LOL,,,

 

[Octopus]

"Noisy" earth?

 

[telectrix]

as above. try it again. might be a duff rcd.

 

[GLENNSPARK]

however....you say it works on the test button.....but not at the load...

whip that RCD fcu off and make sure the outgoing CPC is connected....it may have come out when you pushed the front on...

or it may be that you didn`t connect it at all....as if the sleeving moved over the conductor then it could have given the impression that a secure termination had been acheaved....when in reality its not...

 

[Meggerman]

Which implies that he has not tested at the load terminals of the device. You test the device not the circuit

Which he did, via the circuit which was connected to the load side of the RCD FCU.

 

[R G]

however....you say it works on the test button.....but not at the load...

whip that RCD fcu off and make sure the outgoing CPC is connected....it may have come out when you pushed the front on...

or it may be that you didn`t connect it at all....as if the sleeving moved over the conductor then it could have given the impression that a secure termination had been asheaved....when in reality its not...

Should have proven all that if he's done the EFLI test before RCD test ,,

 

[HappyHippyDad]

If the Zs is 0.9 then I don't see the touch voltage being set @ 25V being the problem, I would check the continuity of the CPC all the way through the circuit though.

I would also try the test at the outgoing terminals of the RCD with the outgoing circuit disconnected first too, to narrow down where the problem may lie, it maybe simply that the RCD is faulty.

Continuity of CPC was proved.

That is a very good idea Spark68 and I should have done that.

Which implies that he has not tested at the load terminals of the device. You test the device not the circuit

Would you not test the circuit as well Trev? When you test an RCD in a CU you test that on the circuit somewhere, generally a socket?

 

[trev]

Which he did, via the circuit which was connected to the load side of the RCD FCU.

So you're ignoring the correct methodology of testing RCDs. Fair enough.

 

[jackhammerJIM]

"Noisy" earth?

not familiar with the metrel . a noisy earth would show on the earth loop test .

 

[trev]

Would you not test the circuit as well Trev? When you test an RCD in a CU you test that on the circuit somewhere, generally a socket?

No, you test the RCD at the load terminals of the device.

 

[Meggerman]

I have had one of those units duff before. Would not trip at 30ma. Did 100ma Ramp test and it operated at 70ma. After that it operated at 23Ma. Still returned it as felt it could be unreliable.

 

[GLENNSPARK]

Should have proven all that if he's done the EFLI test before RCD test ,,

yes of course...

sorry guys.

 

[MDJ]

So you're ignoring the correct methodology of testing RCDs. Fair enough.

It is getting a bit like Fred Carney's circus in this forum lately Trev LOL

 

[SirKit Breaker]

I don't know what all the fuss is about, i once spent and age trying to find out why an RCD wouldn't trip, i was testing on the supply side, took a while for the penny to drop, and not before i had stripped the bloody thing out before i realised what i had done.

So maybe i am a waste of space after all! :dunce2:

 

[Meggerman]

No, you test the RCD at the load terminals of the device.

Yes, I would for a dead accurate reading of device not affected by earth leakage out on the circuit.