Crabtree RCCB not tripping -help!

[Marcus Vaughan]

Hi all.

So the Crabtree old style in my hand failed the I delta n test (times 1). But passed the 5 times test.

So I have replaced it with the one in the board. Supposedly reconditioned - and that’s failing both tests but mechanical works.

I am wondering if I am missing something here with my testing.

I am testing through a socket outlet.

Anyone any ideas other than replace with new?

 

[Lucien Nunes]

Have you checked for N-E faults? These can interfere with both MFT tests and the operation of the test button.

 

[Marcus Vaughan]

Have you checked for N-E faults? These can interfere with both MFT tests and the operation of the test button.

I’ve not tested all those protected circuits no. Just the one I have been working on.

I think I’ll swap out with another RCCB before tackling that one - off to pick one up now.

 

[buzzlightyear]

Their is no reconndion rccb in my book unless it was a dud .
You need a new one .
Try testing to the board nearest socket to the board .

 

[dinger809]

Are you definitely testing at 30mA? I’ve done it before where I’ve accidentally switched the tester onto 100 and it registers as a fail

 

[Midwest]

Concur with the neutral earth fault possibility. One of the occasions I would consider testing RCD at CU.

 

[ruston]

Try testing at the RCD directly . But as has been said check the other circuits too.

 

[buzzlightyear]

I concur me self .

 

[buzzlightyear]

I bet the op has been pulling his hair out and the customers has well.

 

[Marcus Vaughan]

I bet the op has been pulling his hair out and the customers has well.

Yes!

 

[Wilko]

Hi Marcus - a couple of things, apologies if you've already done these .
Test with nothing on the outgoing side of RCD.
Confirm tester set to AC and batteries are good.
Target for 1 times with BS4293 is 200ms.
If the RCD is needed for additional protection as per Reg 531.3.6 it turns out that BS4293 devices aren't mentioned on the list anymore. But guidance below states as long as 5 times meets 40ms then it's ok to continue to use the BS4293 device.
http://www.elecsa.co.uk/Documents/Contractor-Documents/Pocket-Guides/Pocket-Guide-25.aspx

 

[Marcus Vaughan]

Thanks Wilco.

I certainly considered not swapping out the original - seeing as it passed the 5 times test - as as you say - is only for additional protection.

I’ve just swapped it out again - and it’s now working.

But - when I tested at the socket outlet - no joy - but tested at the board (to be honest) - and it’s fine.

I’d like to get my head round what’s gone on here.

Best get back to work.....

 

[Deleted member 26818]

Hi Marcus - a couple of things, apologies if you've already done these .
Test with nothing on the outgoing side of RCD.
Confirm tester set to AC and batteries are good.
Target for 1 times with BS4293 is 200ms.
If the RCD is needed for additional protection as per Reg 531.3.6 it turns out that BS4293 devices aren't mentioned on the list anymore. But guidance below states as long as 5 times meets 40ms then it's ok to continue to use the BS4293 device.
http://www.elecsa.co.uk/Documents/Contractor-Documents/Pocket-Guides/Pocket-Guide-25.aspx

That handbook is out of date now.

 

[buzzlightyear]

socket outlet - no joy - but tested at the board (to be honest) - and it’s fine.

loose connection some where ,is it a ring or radial.

 

[Marcus Vaughan]

loose connection some where ,is it a ring or radial.

Both.

I was working on an existing outside lighting spured from a ring.

I didn’t disrupt the ring but did test ring continuity whilst at the board. No problems found.

 

[Marcus Vaughan]

Are you definitely testing at 30mA? I’ve done it before where I’ve accidentally switched the tester onto 100 and it registers as a fail

Yup. I’ll look out for that though.

 

[Wilko]

That handbook is out of date now.

So are you saying it is incorrect?

 

[Midwest]

Both.

I was working on an existing outside lighting spured from a ring.

I didn’t disrupt the ring but did test ring continuity whilst at the board. No problems found.

What was the IR test results?

 

[Marcus Vaughan]

What was the IR test results?

>999 megohms.

It’s my MFT I am doubting.

Might test my own home later.

 

[buzzlightyear]

Which mft have you got.