Faulty BG RCBOs anyone else

[ebee]

I installed a BG consumer unit in August with RCBOs.
A 6A RCBO failed in September - tripped and would not reset (outgoing circuit disconnected).
A 32A ditto in December.
Any known issues with BG compact RCBOs or is this just bad luck?
Thanks

 

[studentspark]

Ive had issues with BG and will not use them any more.
Its the main switch that was the problem Ive had two fail on tightening the screws, and this is with a torque screwdriver.
The mechanism gives way

 

[sparkwright]

Loosely related, where I have been forced to use BG accessories, the grid switch modules have failed in a matter of days, and the terminals on sockets have broken away before or after the screws have been fully tightened.

This stuff is supposed to have a 30 year guarantee.

 

[Deleted member 18243]

The great Thomas Nagy is coming to dislike BG equipment; see here from 8:50...

I've used the odd BG item and have found them to be good value when working to a tight budget. I've had no problems, and I like the fact that they have the word BRITISH in their name!

Thomas also discusses, earlier in the video, how a young electrician posted proudly a photo of his first consumer unit on Twitter - only to be slated by a nit-picking mob. Rather than encouraging the youngster, the mob seemed to want to have him hanged.

 

[dannyboi2003]

I've had the same problem as studentspark with the main switch terminals breaking, I was using a torque screwdriver on the correct setting.

I'm also having weird issues with their new (now standard) mini RCBOs randomly tripping out for no reason, usually it happens when you plug something in but can reset it straight away with no issue, I have a few appliances that trip them out when first plugging them in every time, the charger for my LED floodlight, my SDS drill and a garden strimmer, I've checked the appliances over and there are no issues with them. Has anyone else had this issue with the RCBOs?

 

[Simon Bateman]

I'm glad it's not just me, I will explain my saga with BG RCBO's !

I rewired the complete house, 3 BG Boards, a 17w Amend3 Twin RCD board in the House, a second 5w board in the utility fed by 10mm2 sub main of the main board and finally a BG garage board that I removed the RCD from,fitted a 40A main switch and three RBCO's feeding lighting radial and two Ring finals for the sockets. Due to the cable length volt drop and including discrimination the rings are both fed from 16A RCBO's rather than a single 32A ring.

Everything tested OK

I then found that the ring feeding my bench tripped when using either the MIG welder or 3hp compressor, so I ordered a pair of Type-C RCBO, both of which were the new Compact type, I swapped the RBCO's out and one of them failed (next to the one being tested) as soon as I ran the RCD test using my tester. ! so I assumed faulty from day one and got a replacement. Now the Welder and Compressor didn't trip the RCBO.... but the hoover, angle grinder and all sorts of "nice" loads did. Then the replacement failed and would not reset - I disconnected the load form the RCBO and it still would not reset, so I put the old (Full size) Type B's back - no further odd tripping but back the problems with the compressor, this continued for several months and my supplier replaced all the faulty RCBO's under warranty.

I'd now had 4 of the compact C-type fail which turned out to be of the same batch so I wrote to BG who very kindly sent me a full set of new 16A Type C compact RCBO from another batch, however these also started tripping every time I used the angle grinder and eventually failed in same way as the others had

As I's had enough of taking the board apart I went old school put the 40a RCD in for earth leak protection and 3x MCB's for over-current, Type B on the lighting and Type C for the rings - Now everything works, the compressor, welder, angry grinder, kettle, bench grinder and I have not had a single "trip" since.

The last RCBO that failed I took apart and found some burning of the contact and a bit of prodding with the DVM discovered a metal oxide varistor that looks like it's supposed to protect the unit had gone short circuit, possibly the noisy nature of the typical workshop loads was taking the RCBO out. What is strange is that the previous full size RCBO can cope with this but the new ones on some occasions did not even survive an RCD test being performed on the neighbouring RCBO !

Progress... in the case is doesn't seem so...

As I swapped out all of my boards for BG I'm stuck with the thankfully the only issue seems to be the crappy compact RCBO and other stuff is OK, I have collected a number of spares though...

 

[boringoldcodger]

angry grinder

Love the typo.

 

[JohnW2]

Love the typo.

I'm inclined to blame the dreaded 'predictive text' - although, I have to say, that as the years relentlessly progress, I not infrequently find my brain and/or fingers doing that sort of 'phonetic typing' these days!

Kind Regards, John

 

[skenk]

Wait, so you've had 6 out of 6 BG RCBO's 'fail'? or could it be -

the rings are both fed from 16A RCBO's rather than a single 32A ring.

 

[JohnW2]

.... or could it be -

... Due to the cable length volt drop and including discrimination the rings are both fed from 16A RCBO's rather than a single 32A ring.

I have to say that I didn't notice (or, at least, 'take in') that. If it's being said that there is a 16A RCBO at each end of the ring, then I can envisage two possible issues which could result in trips ...

Firstly, if large loads (>16A total) were connected fairly close to one end of the ring, then the RCBO at that end could trip because of over-current. In practice, that situation is probably not very like to arise - but, probably much more likely ....

.... Secondly, if there were just a slight difference in L or N path impedance in the two arms of the ring (relative to the position of the load) (e.g due to an imperfect joint somewhere), then when there was a substantial load current flowing, it would be quite possible for there to be a >30mA imbalance been L & N currents at the RCBOs, hence resulting in a 'residual current trip'.

For example, if there were, say, a 21A load one third of the way (one third of total ring length) around the ring, then one would expect 14A (in both L&N) to be taking the short route to the CU and 7A (in both L&N) to take the 'long' route. However, if due to, say, slightly different L path impedances, the L currents were 13.970A in the short leg and 7.030A in long leg (with N currents 14.000A and 7.000A respectively), then one or both of the RCDs ought to trip.

I would conclude from this that putting an RCBO (as opposed to an MCB) at both ends of a ring is probably potentially 'asking for trouble'.

Kind Regards, John

 

[SUNRAY]

If it's being said that there is a 16A RCBO at each end of the ring

I didn't interpret it this way, my assumption is a regular ring final downrated to a 16A device. And another similar unrelated circuit.

We provided the temp supply for an event and were asked at the last minute for a 63A feed. Unfortunately the largest we had in that particular board was 32A RCBO's and decided to double up. I can categorically state that doubling up RCBO's, and I assume RCD's, does not work.

 

[JohnW2]

I didn't interpret it this way, my assumption is a regular ring final downrated to a 16A device. And another similar unrelated circuit.

I must say that I'm still inclined to my interpretation, particularly given that ...

..... Due to the cable length volt drop and including discrimination the rings are both fed from 16A RCBO's rather than a single 32A ring. ...

... was followed by ....

.... I then found that the ring feeding my bench tripped when using either the MIG welder or 3hp compressor, so I ordered a pair of Type-C RCBO, both of which were the new Compact type, I swapped the RBCO's out and one of them failed (next to the one being tested) as soon as I ran the RCD test using my tester.

However, I obviously may be wrong (and you right) - hopefully Simon will clarify!

Kind Regards, John

 

[SUNRAY]

I must say that I'm still inclined to my interpretation, particularly given that ...

... was followed by ....
However, I obviously may be wrong (and you right) - hopefully Simon will clarify!

Kind Regards, John

 

[SUNRAY]

again my interpretation was that he assumed the 16A was not man enough for the task or perhaps concluded the 16A versions have a problem and upgraded to the regular 32A on both rings.
However now I see your reasoning I'm not 100% either way but I hope my original conclusion was correct.

I'll put forward that in the 60's and 70's when electrics were being upgraded from the 40's and 50's 15A radials it was far from uncommon to form them into a ring but leave them fed from both ends with 15A fusewire and the problem with that was when a fault occured both fuses blew but Mr average would pull fuses until he found a failure, repair it with 15A wire and when the circuit jumped back into life would not think of looking any further for another blown fuse. In fact that reminds me, one of my daughters houses had that with MCB's when she moved in and that was this century in, I'd guess, an 80's house.

 

[JohnW2]

... However now I see your reasoning I'm not 100% either way but I hope my original conclusion was correct.

I think we have to await the referee !

I'll put forward that in the 60's and 70's when electrics were being upgraded from the 40's and 50's 15A radials it was far from uncommon to form them into a ring but leave them fed from both ends with 15A fusewire and the problem with that was when a fault occured both fuses blew but Mr average would pull fuses until he found a failure, repair it with 15A wire and when the circuit jumped back into life would not think of looking any further for another blown fuse. In fact that reminds me, one of my daughters houses had that with MCB's when she moved in and that was this century in, I'd guess, an 80's house.

Indeed, it's not only an 'ancient' concept - it's not that uncommon for us here, today, to see mention of rings with MCBs at both ends (I think that, in particular, eric sometimes talks about it) - and the greatest concern there is about isolation (in the hands of someone {and we know there are some} who does not satisfactorily 'test for dead').

I think I've only ever come across it once, and that was due to a wiring mistake (and, presumably, no proper testing) - with two rings 'cross-connected' (i.e. each ring had one end going to one MCB and the other end to the other MCB).

Whatever, that's MCBs and, as I said, if anyone tries it with RCBOs I think that they really are 'asking for trouble' (and not just for the above reason), for the reason I explained!

Kind Regards, John