Rcd Testing

Hi all,

Can I ask a HUGE favour.

Can any and all of you who can and will please record all details of ANY and ALL RCD's that give you ANY issues during testing, can you please post them in this thread.

This is SERIOUS so I will need if requested accurate details of devices, situations, failures, locations, and if you are willing, please keep the failed devices.

Also, if you can recall full technical details of any and all previous failures as far back as you can remember then that would be even more useful.

Please note, the more information, and the more accurate and reliable the information the more useful it will be.

Please if you can treat this as a serious technical fact finding exercise, it is important, please trust me.

If you can, think of this as generating evidence for a court case, and treat it as such, then we will all benefit.

VERY long story that as yet I can't relate, but, it is in our best interests, please just trust me on this one!

Are you looking for new out of the box failure stats or in service failure stats

Both please Murdoch, as many with as much detail as possible please.

On a caravan park every year I replace at least 2 RCDs in the 16 hook up boxes main problem RCD does not trip on test button but will on RCD test Meter.most RCDs are tenby brand.

Thank you Adrian,

Can you please, please, keep the faulty devices, and record as much details as possible and record them in this thread if you can, there is a reason for this, as it will be useful in the long run.

We install mainly MEM and I would say the failure rate is very very low.

To,date I do bot think I have ever had a faulty one.

From M and G, MEM, WYLEX, CGD, CED,,SqD

But now that i am aware...

I haver NEVER had a HAGER 4293 [?] pass an test if there is solar PV connected to it

or is that totally irrelevant from what you are looking for?

I replaced 2 wylex RCDs  last year, they would not rest. They were installed in a hot plant room. I think they had been installed 6 years.

House i am going to tomorrow, when i first went to have a look at nusance tripping (due to leaking shed) i discovered the Wylex RCD test button was not working, disconnection times were ok . They will have it replaced, not tomorrow though. When i replace it i can keep the old one for you if it is of any use.

steptoe said:

I haver NEVER had a HAGER 4293 [?] pass an test if there is solar PV connected to it

or is that totally irrelevant from what you are looking for?

Click to expand...

It's more to do with failure rates Steps tbh.

ive got a pile of spare RCDs been removed from old boards etc, ill test a few if its any use to you

I've recently had to change a 30mA rcd as it was tripping at 13ma (under half obv) any good to you?

Here's a theory.....does the consumer ever test the rcd quarterly....I came across one that didn't trip once and it was fairly new and on a previous test cert said it worked (couple of years ago) so I gave it a tap.....guess what it worked on test and also worked on an rcd test and has worked ever since.....

Apart from the obvious of why to test quarterly...

A theory....testing it quarterly makes the spring inside contract back....If it's in the open position over long periods of time,does this make molecular compound of the spring set in the "expanded" position? By making it contract again resets the molecular compound again,thus making it spring back properly....just a thought

OK, haven't got deatils but RCBOs fail more often than RCDs, quite often within a couple of years of being fitted.

Most notable failure I have experienced was a Hager unit at about 20 years old - it was fitted as main incomer for a cartridge fuse board. When tested it didn't resond to 1x and test time for 5x was something like 200mili secs. This RCD had allowed a fire to propogate in a garage caused by a metal buckle dropping down behind plastic shelving unit, where it got jammed between unit and cable. Buckle somehow shorted cable and set fire to plastic shelving. That board and RCD, was a Hager unit.

I have also had a Control Gear RCBO fail after a few weeks. The failure being the trip lever was broken, but left the circuit live. This I suspect was the work of a plumber who had failed to uncoil is extension lead, kept tripping the RCBO and forced the RCBO 'ON'. That was about 5 years ago when CG first appeared on the market.

On a recent EICR on a commercial premises I found a load of Memshield 2 RCBOs, around 15 years old, with x1 times mostly in the upper 30s. As they didn't technically fail they are still in but I am hoping that following some future refurb works they will be coming out. I can probably liberate 1 or 2 before then if you need them.

An RCD failing a test could be down to the RCD or it could be the test equipment needing recalibration. I regularly test my extension lead rcd, partly for my own safety and also to verify that my tester is giving the same results which a yearly recalibration might miss.

This was a nasty one! http://talk.electricianforum.co.uk/topic/28813-intermittent-time-delay-rcd-failure/

Recent failures,

CED... SEP 2015... 1 of the 2 RCDs in a brand new domestic consumer unit, failed to trip on tester or button

Merlin Gerin C20 RCBO. Protecting general purpose checkout sockets in a shop, failed to trip on test button or tester. Installed approx 5 years previously

Wylex 30mA RCD. July 2015 Incommer on a CU in a farm workshop. Ramp tested at 33mA failed to trip at 30mA. Unknown when installed.

MEMshield 1. April 2014 (I think) Type 3 16A RCD to mains room socket in a school. Failed to trip on tester or button and made a strange noise. While making a note of failure. Device then tripped with a flash and a large bang. Installed early 1990s

September 2013... Merlin gerin C20. As above. General checkout sockets again. Another branch in the same chain.

April 2011. A couple of C32 merlin gerin C32 RCBOs protecting workshop sockets in a colllege. Did not trip, made funny noise instead.

April 2011. MCG RCBO installed in a merlin board in a college, instructors office sockets. Tripped but kept circuit live in tripped position!, possibly counterfeit device? (with voltage probes on outgoing terminal, the output would falter for a moment as it tripped but come back on once it was tripped... switching off the slider on the board killed the output, so it was not a backfeed)

Thats the ones I can remember!

I will look into my records tomorrow

I will look into my records tomorrow

Still want information on failed RCDS?

Doing a load of EICR for a local authority. Had 3 Wylex 30mA RCDs fail last week. Test button would work once then once I reset it, it stops working and they wouldnt trip at all doing a ramp test or for trip times. All 3 installed 5 years ago when the properties were rewired. Think its down to not being tested quarterly.

Doing more this week and next if you still want details of failures?

Yes please, as much detail as possible including part numbers and batch numbers even.

However, it must be factual please.