Ongoing mk rcbo faults

[JB1970]

Not sure if anyone has further information on this but I'm getting nowhere with MK tech department.

I did a CU change recently & fully populated it with MK Sentry RCBOs - all tested ok. I've returned a short while later to complete some works & while testing found all 3 of the B6 RCBO's were faulty. Same fault on each, failing the x5 test at 180 degrees. Thought it may be my tester, had a spare with me so fitted that one & it tested ok. Went to order another two from Screwfix & someone has posted a comment about this same fault.

I've e mailed MK tech with the details - no response so I called them a couple of days later. As soon as mentioned the nature of the fault the first person covered the phone mouthpiece waited a few seconds & hung up! Called back & spoke to someone else who said they were aware of it, it was being investigated & an official response would be made within a day or two (this was June 16th). He wouldn't tell me the affected serial numbers (I know some of them) Heard nothing since.

A bit concerned because I've fitted quite a few of these. The serial numbers are on the reverse side so you need to remove the busbar to get them out & check. Bear in mind that they test OK initially & fail at a later date...

 

[Midwest]

I've fitted some MK RCBO's recently, no issues. I noticed you posted on another forum, and see you were directed to another thread; IET Forums - Faulty RCBOs You may wish to stick with that one? If not, I would suggest you convey how you carried out your series of tests first, before any suggestions are made here.

 

[hightower]

Redacted

 

[Midwest]

It might be worth contacting Electrical Safety First, to see if they have been given any product recall information.

 

[Midwest]

Redacted

Yep got confused with the dates on the IET thread, thought I was reading an old thread, in fact quite new thread. Apologies, nothing sinister!

 

[JB1970]

Yep got confused with the dates on the IET thread, thought I was reading an old thread, in fact quite new thread. Apologies, nothing sinister!

I did also post on another forum as you say to try & find out more information. I found the other post that one of the replies points to & it does indeed appear to be the same issue affecting the B6 RCBO that I have, specifically passing all but the x5 test at 180 deg.

Testing was carried out directly at the RCBO terminals with no load connected. 0 deg @ 30mA, 180 deg @ 30mA, 0 deg @ 150 mA, 180 deg @ 150 mA at which point the test is cancelled as the RCBO does not trip within 40mS.

A couple of people are saying that there is a recall. MK have told me there is a known problem & to wait for their official announcement regarding the issue. The person I spoke to was very cagey about what he would & wouldn't tell me & specifically said that he'd been instructed not to divulge any details. When asked if he would confirm whether the serial number range I had been informed about elsewhere was the only range affected, he wouldn't even confirm the numbers I already knew about.

I've been checking the Electrical Safety First site regularly & there's nothing on there to date.

 

[Midwest]

I expect they are being cagey, cos if they have a faulty product, it's going to be expensive for them. I would expect some recompense to go back and check the RCBO's (serial numbers) I've installed.

 

[Midwest]

I was going to post in the Arms section, but perhaps it's better here to keep everyone up to date, as long as we don't mention specific terms!

Would appear the recall is in progress, as some are already aware, and thanks to JB for bringing it to my attention, or not .

If you are not aware here's a couple of links;
MK Sentry RCBO Exchange
http://www.rcboexchange.co.uk/resources/How to Identify Potentially Affected Product.pdf

I have two or more installlations, where potentially I have these RCBO's, albeit they tested within parameters. My question is, having not been in this postion before, I expect it would be reasonable to expect recompense from MK, for checking to see if they are indeed the faulty RCBO's as indicated and actually replacing them. I'm not referring to the product cost, but my time and labour.

I will ring MK in the next few days to enquire, but if anyone already has done so, or has been in this situation before, I wonder if you can advise?

Thanks.

 

[mache]

I would be interested to hear how you get on with this.
Certainly there is a case for recompense for replacing faulty units, however I'm not convinced that MK would pay for going to check installations on the off chance because the installer did not keep records of serial numbers of installed devices.
I suspect that few do keep records, however this incident is a good indicator of the fact it could be a good idea in the future, especially for saftey related devices.

 

[Midwest]

I would be interested to hear how you get on with this.
Certainly there is a case for recompense for replacing faulty units, however I'm not convinced that MK would pay for going to check installations on the off chance because the installer did not keep records of serial numbers of installed devices.
I suspect that few do keep records, however this incident is a good indicator of the fact it could be a good idea in the future, especially for saftey related devices.

You do have a point there, but we purchase 100's possibly thousands of products, but we buy from reputable manufacturers/sources and don't expect them to fail. I had an issue recently, which I posted here about a faulty FCU which didn't isolate the live terminal. Should we record the manufacture date of all faceplates we install?

 

[Deleted member 9648]

I did also post on another forum as you say to try & find out more information. I found the other post that one of the replies points to & it does indeed appear to be the same issue affecting the B6 RCBO that I have, specifically passing all but the x5 test at 180 deg.

Testing was carried out directly at the RCBO terminals with no load connected. 0 deg @ 30mA, 180 deg @ 30mA, 0 deg @ 150 mA, 180 deg @ 150 mA at which point the test is cancelled as the RCBO does not trip within 40mS.

A couple of people are saying that there is a recall. MK have told me there is a known problem & to wait for their official announcement regarding the issue. The person I spoke to was very cagey about what he would & wouldn't tell me & specifically said that he'd been instructed not to divulge any details. When asked if he would confirm whether the serial number range I had been informed about elsewhere was the only range affected, he wouldn't even confirm the numbers I already knew about.

I've been checking the Electrical Safety First site regularly & there's nothing on there to date.

This might be the problem, it is a known characteristic that some RCBO's do not test directly to the terminals for some obscure technical reason. A short pair of tails are required or testing on a circuit connected to the RCBO. MK should be aware of this though if it affects their product.

 

[westward10]

You can test direct to the terminals of an MK rcbo, as far as I am aware it is only Memshield 2 rcbos which are essentially an mcb with a module put to it that you cannot. I suspect MK are on to their friends in China to resolve this. Solution avoid MK.

 

[richy3333]

MK, say no more. Bag o sheeet. Not the make it once was

 

[Midwest]

Look at other threads on the over all on this subject might want you not installing any manufactures product.

 

[mattg4321]

Serious question. Why would you not be able to test direct to the terminals of a Memshield 2 RCBO/Pod?

 

[davesparks]

Serious question. Why would you not be able to test direct to the terminals of a Memshield 2 RCBO/Pod?

Because the rcbo is made by adding a pod to the mcb, this retains the existing live terminal, but the live sensing coil is in the pod, after the output terminal.
So testing at the terminal screw doesn't include the live sensing element in the test.
The test connection needs to pass through the tunnel in the pod where the circuit conductor normally goes, so either a short piece of cable or a long probe tip such as the one megger ship with their mfts

 

[Midwest]

An update on my experiences. I have two installations where I have used the suspected faulty RCBO's. First one was rather easy; was on an installation where I'd done the dead tests on a radial, and I went back the other day & carried out the live tests. The RCBO failed the x5 @ 180", which appears to be the common fault. Spoke to my wholesaler, who said bring it back and we'll replace it. However, when I did the manger said MK are carrying out exchange on installed products, but eventually they did just swap it for me.

I rang the 'RCBO Exchange' helpline 0800 376 0013 (don't ring technical, they don't have a Scooby Doo), and eventually spoke to someone. The Bobby Moore is, (most stop $hi$ jokes) products not installed can be replaced at point of sale, installed products have to go through MK, I can see some severe arse covering going on here (from my customers point of view!). You fill out the proforma (#8), MK will make contact with you and send you the appropriate replacements to install. Seems they are replacing the batch coded items, even if they tested okay.

I briefly asked about reimbursement for my time, and MK are offering 30 sockets, or something, but I made no comment to that. BE ADVISED, MK asked how I was aware of recall, I stated originally this forum and they were very interested in forum web address. So perhaps any discussion on recompense, should be in the Arms?

 

[Ian Taylor]

Not sure if anyone has further information on this but I'm getting nowhere with MK tech department.

I did a CU change recently & fully populated it with MK Sentry RCBOs - all tested ok. I've returned a short while later to complete some works & while testing found all 3 of the B6 RCBO's were faulty. Same fault on each, failing the x5 test at 180 degrees. Thought it may be my tester, had a spare with me so fitted that one & it tested ok. Went to order another two from Screwfix & someone has posted a comment about this same fault.

I've e mailed MK tech with the details - no response so I called them a couple of days later. As soon as mentioned the nature of the fault the first person covered the phone mouthpiece waited a few seconds & hung up! Called back & spoke to someone else who said they were aware of it, it was being investigated & an official response would be made within a day or two (this was June 16th). He wouldn't tell me the affected serial numbers (I know some of them) Heard nothing since.

A bit concerned because I've fitted quite a few of these. The serial numbers are on the reverse side so you need to remove the busbar to get them out & check. Bear in mind that they test OK initially & fail at a later date...

Just ongoing with a CU replacement. All MK and Sentry RCBOs. After fitting and testing 4 other units all OK and in spec., I fitted a 16 Amp RCBO, it tested OK at 1 and 5 times, but was noisy in operation - not happy. The next circuit was a 10 amp this failed the test at 5 times with a 40.0 msec at 0 degrees reading! This is why I came on to the forum.
Not happy with the quality of MK products and find the screws poor quality as well. Last time I will be fitting this manufacturer.
Ian T

 

[davesparks]

I thought MK had discontinued their CUs?

 

[timhoward]

I thought MK had discontinued their CUs?

Screwfix are certainly currently selling them on-the-ultra-cheap.