MK Sentry RCBO Fault

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...

Hi, I have just ripped out my MK CU and replaced it with Hager ! Sad state of affairs. But at least you did'n't fit wylex Check the main switch as well

DS

There is a known fault and a recall for these RCBOs. We fitted a couple of their boards and had to swap all the 6A RCBOs as they did not trip at 5xIn. Did you also notice there are no terminals available in the earth bar to connect bonding conductors in the new amendment 3 boards?

Yeah MK wouldn't confirm whether it was only 6A RCBO's or whether there were any with serial numbers I was not aware of. The serial numbers I've found out about are F1534 to F1552 and F1601 to F1602. The ones I had were in that range. Until I can find something official from MK however I'm reluctant to start retesting. As said the ones I had passed initially. Retested after splitting some circuits up & that's when I found the issue. I definately had bonding terminals in my AMD3 board though?

Edit:
This sort of thing really gets on my tits, when confronted about it MK denied all knowledge of faulty RCBOs and couldn't understand what the problem was when asked where the 2 bonding terminals had gone from the new boards. We wasted time retesting things and tried using more than one test kit as we couldn't understand how an RCBO could trip ok at 1x but not at all at 5x.

MK technical? More like MK testicle, a load of balls!

deadshort said:

Hi, I have just ripped out my MK CU and replaced it with Hager ! Sad state of affairs. But at least you did'n't fit wylex Check the main switch as well

DS

Click to expand...

One of the boards I swapped to MK was because of constant Chint RCBO failures. Would pass all testing on the MFT but when pressing the test button would just chatter then pop & smoke!

JB1970 said:

I definately had bonding terminals in my AMD3 board though?

Click to expand...

Strange, we fitted 2 10 way boards, both had a terminal for the main earth, 10 terminals for the circuits and one bond terminal that was being used to earth the enclosure.

Echo the husky said:

Edit:
This sort of thing really gets on my tits, when confronted about it MK denied all knowledge of faulty RCBOs and couldn't understand what the problem was when asked where the 2 bonding terminals had gone from the new boards. We wasted time retesting things and tried using more than one test kit as we couldn't understand how an RCBO could trip ok at 1x but not at all at 5x.

MK technical? More like MK testicle, a load of balls!

Click to expand...

They confirmed it to me but said I'd have to wait for an official announcement

The wholesaler we got the gear from told us when we said they were faulty.

Echo the husky said:

JB1970 said:

I definately had bonding terminals in my AMD3 board though?

Click to expand...

Strange, we fitted 2 10 way boards, both had a terminal for the main earth, 10 terminals for the circuits and one bond terminal that was being used to earth the enclosure.

Click to expand...

Mine had 14 terminals for CPC, 2 for bond & 1 main usable

Perhaps they changed the design, I took some photos of the install, they are dated 25.05.16.