RCBO tripping, no load attached to it

[Sard]

Hi,

I had a new circuit put in by an electrician as part of a CU relocation job. The circuit is on a 32A RCBO and has a 6mm2 TE cable wired into it. The work was done a year ago and at the time it was feeding my oven and everything worked well. As part of some renovation work, we've taken out our oven and will be wiring in the induction hob onto this circuit. It's been turned off at the CU for about 4 weeks. I have since tried to connect the Induction hob and the RCBO popped immediately, so I took the hob off, inspected the conductors, and wired it only into a 45A DP switch with no load attached it and again it popped immediately and I could see a small puff of smoke come out of the RCBO. I'm confident the conductors or the cable haven't been damaged in any way. I've contacted the electrician to see if he can come down and test but in the meantime I'd appreciate any thoughts on what could be going on here?

 

[EFLImpudence]

I would say the puff of smoke says you need a new RCBO.

However, get the circuit tested before fitting a new one or it might do the same - not sure why, though, they are not supposed to smoke.

 

[Sard]

Thank you, that's really helpful. What type of scenarios would cause an RCBO to die like that? Could it be that when I connected the hob originally, there may have been a short (bad connection?) Causing it to trip but also die at the same time? Prior to that it worked and was supplying the Oven.

 

[EFLImpudence]

Thank you, that's really helpful. What type of scenarios would cause an RCBO to die like that?

Other than an internal fault - nothing really. They are supposed to protect against things that would cause that.

Could it be that when I connected the hob originally, there may have been a short (bad connection?) Causing it to trip but also die at the same time?

Not really.

Prior to that it worked and was supplying the Oven.

Coincidences do happen.

 

[Sard]

Thinking ahead, if I do need a new RCBO, are they interchangeable between brands? The Consumer Unit is Fusebox brand but the RCBO modules are not stocked by the electrical shops where I live. I was thinking of buying one pre-emptively as the electrician is booked for Wednesday.

 

[Murdochcat]

Fingers crossed your spark will carry spares in his van

And no you shouldn’t mix and match

 

[Risteard]

Thinking ahead, if I do need a new RCBO, are they interchangeable between brands?

Absolutely not. Never get parts for an Electrician - we don't appreciate it and they will almost certainly be wrong.

 

[Taylortwocities]

Absolutely not. Never get parts for an Electrician - we don't appreciate it and they will almost certainly be wrong.

Here here.
Would you try and fit a Ford oil filter on your BMW???

Consumer Units are type-tested as an assembly. It will no longer meet the product certification if you throw in a foreign object.
More practically, different makers have different pitches of the busbar. So it may not physically fit.
If nothing else, It will look just awful.

 

[opps]

Here here.
Would you try and fit a Ford oil filter on your BMW???

Consumer Units are type-tested as an assembly. It will no longer meet the product certification if you throw in a foreign object.
More practically, different makers have different pitches of the busbar. So it may not physically fit.
If nothing else, It will look just awful.

In the past, I have seen electricians bend the busbar to accommodate the new MCB. I have long wondered how much that damages the integrity of the busbar.

BTW, it is hear hear, not here here

 

[JohnW2]

Here here. ... Would you try and fit a Ford oil filter on your BMW??? .... Consumer Units are type-tested as an assembly. It will no longer meet the product certification if you throw in a foreign object. .... More practically, different makers have different pitches of the busbar. So it may not physically fit.

Indeed - but I must say that I've often wondered how on earth this messy and inconvenient situation was allowed to arise.

In very many walks of life, the practice is for components to be manufactured so as to comply with a Standard which ensures that they can be used (interchangeably') in many contexts. I suspect that a good few components in a Ford car would also work in a BMW, because both car designs require components that comply with the same Standard.

This has happened with plugs/sockets, since BS1363 ensures that products complying with that Standard are interchangeable, regardless of 'make'. Think of the chaos which would result if the manufacturers of 13A socket insisted that only their make of 13A plugs should be used with them - or the same with lamps/bulbs and lamp holders ... or whatever !!

It's hard not to suspect that the underlying reason for the situation we have with CUs and their devices was due primarily to 'commercial' considerations/interest! In fact, one wonders why it was even 'legal', if it could be established that the primary motive was an 'anti-competition' one!

Kind Regards, John

 

[Taylortwocities]

I

BTW, it is hear hear, not here here

Didn’t realise this was a correction facility.
I’ll take care to mind my peas and queues in future.
And will read your future posts very carefully !

 

[opps]

Didn’t realise this was a correction facility.
I’ll take care to mind my peas and queues in future.
And will read your future posts very carefully !

It wasn't my intention to cause offence.

I often make errors and am happy to be corrected, so long as the person correcting is not being condescending. In no way was I attempting to be condescending.

 

[Murdochcat]

sadly there are far too many so called "sparks" still mixing makes .............

 

[JohnW2]

sadly there are far too many so called "sparks" still mixing makes .............

I'm sure there are, not to mention 'non-sparks' - but, as I recently wrote, I remain surprised that a situation was allowed to arise in which that might 'matter'.

As I said,imagine if one was not 'allowed' to 'mix makes' of 13A plugs and sockets.

Standards are meant to be used to avoid such a mess, as they are in so many other walks of life..

 

[Murdochcat]

I'm sure there are, not to mention 'non-sparks' - but, as I recently wrote, I remain surprised that a situation was allowed to arise in which that might 'matter'.

This reg, no doubt was made to happen, by the manufacturers who have undue influence over JPEL/64, obviously worried about 3rd party products costing them profit.

That said I always went the extra mile to get the same OEM parts when making changes to installations .................