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.

 

[Marcus Vaughan]

Which mft have you got.

Megger 1721

 

[buzzlightyear]

On testing with the megger testing on rcd 30 1x then 5 x try and reset the megger back .to see if any different.

 

[Marcus Vaughan]

On testing with the megger testing on rcd 30 1x then 5 x try and reset the megger back .to see if any different.

Reset?

 

[telectrix]

think he means retest after it's tripped on x5. you need to think laterally with buzz, sometimes even standing on your head in a Vat of wine.

 

[Marcus Vaughan]

think he means retest after it's tripped on x5. you need to think laterally with buzz, sometimes even standing on your head in a Vat of wine.

Ah. OK.

 

[buzzlightyear]

Reset the megger where you see the spanner on it.or do you not know how to do it ,and it not nike neather.

 

[Midwest]

>999 megohms.

It’s my MFT I am doubting.

Might test my own home later.

Not that then.

 

[Deleted member 26818]

So are you saying it is incorrect?

Yes.
531.3.6 RCDs for additional protection
The use of RCDs with a rated residual operating current not exceeding 30 mA is recognized as additional protection in compliance with Regulation 415.1. These RCDs shall be provided to comply with the requirements of Regulation 411.3.3.
RCDs for additional protection in AC installations shall comply with:
- BS EN 61008 series, or
- BS EN 61009 series, or
- BS EN 62423.
Where installed at the origin of a final circuit or a group of final circuits, an RCD with a rated residual current not exceeding 30 mA may provide fault protection and additional protection simultaneously.
NOTE: Consideration shall be given to the division of the installation (see Regulations 531.3.2 and 314.2).

 

[Wilko]

Hi - yes, I read the BBB too. The regulation does not include the BS4293 devices, so my understanding of the regulation is they may not be used for additional protection. To this end Elecsa has stated -
"When the 17th Edition (BS 7671: 2008) was published, only BS EN 61008-1 and BS EN 61009-1 were still listed (Regulation 411.4.9 refers). However, this does not preclude the use of RCDs to BS 4293, BS 7288 and BS 7071, where appropriate, for fault protection and/or additional protection, provided they meet the relevant operating time requirements."
Just to confirm, are you saying this advice from Elecsa is incorrect? And so these devices may not be used?

 

[Deleted member 26818]

That advice is both correct and incorrect.
Where such devices are installed in existing installations, then as the advice states, their use would not be precluded, provided they meet the relevant operating time requirements.
However their use would be precluded in a new installation or as a replacement in an existing installation.
In such circumstances, the designer/installer would have to declare it as a departure and attest that safety has not been compromised.

 

[Wilko]

Thanks for clarifying. I agree on their use as you've said, for what it's worth .