My consumer unit keeps tripping, is this connected to the smart meter?

 Thank you, Peter, and apologies to you, Jan, for going off at a technical tangent, but this is such a strange phenomenon that I think it deserves technical discussion involving people who know what they’re talking about (which rules me out!). My reading is getting me more and more confused, but this graphic helped:
  

Since most households now use many of the devices that call for a type A at least (e.g. LED lighting, variable-speed-drive washing machines), Could this influence Peter’s response at all? (I was happy to see when I checked that my breakers are all Type A RCBOs). I still wonder, though, whether the type of RCD or of the CU enclosure could in any way explain this unexpected tripping apparently in response to a burst of EMF radiation in the middle of the night. Someone must have done the tests - OVO’s own meter scientists, DCC and the CH manufacturers EDMI, WNC and Toshiba. 

There are certainly additional influences with installed equipment on RCD/RCBO devices - hence the array of options when fitting. DC (or DC behaviour) can affect triggers but the fundamental question here is .. what happens in the near vicinity at, or around, 3:50am?

Depending on the surroundings, external influences might be a cause .. if you remember, I quoted some device tripping on a large building site, caused by 2 way radios used during construction.

I wonder if the data from the meter usage gives any clues about on-site activity at that time  

Hi,

For the previous 2 nights I have been awake at 3am and stayed awake, so I know the time it tripped.

I have decided to go with a new CU as I think it's good to upgrade after 26 years.

The cable doesn't run past the meter.

I am not even sure the metal CU will fix the problem.

It will be fitted next week, so I will let you all know either way.

Thank you all for your advice.

​@Jan71 you are so good at feeding back and ticking off the questions I wish there was some kind of leader table / reward for having spent the time to do that.  So many times we get ghosted when trying to narrow the options that you just get left hanging wondering if you even got close to solving the issue.

If the plastic CU has been there that long then a metal one would be a timely replacement. If it went away then it would be support for the RF idea but still not definitive. The cable not running past the meter is a blow but I'm not completely sure it's RF triggered anyway.

Regarding the diferent types of RCD I would be trying all of them to see if any of them worked there and if they did what was special about that particular type.

As for testing RCDs against RF fields, well, you could spend a lifetime exploring combinations of different parameters: Near field / E coupling / M coupling, Far field EM coupling, direct coupling, cable coupling, frequency, power, continuous and pulse are just for starters. RCDs are generally immune to RF fields they are likely to encounter it's just that they may have a particular sensitivity based on their particular manufacturer but it seems to be so rare as to be not worth the effort. In this case given the frequency band in use (GSM or radio) the RCD is actually in a Near Field situation (within a small fraction of a wavelength) and the effects fall off as the cube of the distance not the square as for Far Field EM coupling. Most devices are tested in a Far Field environment.

Peter

Thank you Peter for your reply.

The new CU is the only option at the moment as the electrician cannot find the cause of the tripping.

There is nothing on the rcd section now, so cannot understand what would cause it to trip in the early hours?

If this doesn't fix it, at a loss what else to try.

I will keep you posted.

To be honest this is not a common problem so it wouldn't have been on OVO's list of suggestions to change to a metal CU case anyway. It was a bit of a head scratcher for us on the forum as well but because of your excellent and detailed feedback it seems likely there was an interaction between the meter and the RCD after all.

Peter

Just to add some confirmation about the interaction, at least between RCBOs and smart meters, I successfully got Scottish Power to pay for an electrician to replace an RCBO after I proved that their smart meter, installed only a couple of inches away from my CU had caused tripping.  The RCBO tripped twice a day like clockwork from the day the meter was installed.  An aluminium foil shield loosely placed around the meter stopped it doing so.  The problem was solved by replacing the RCBO, which unlike all the others in the CU had a neutral tail.  When replaced with one with no tail everything was perfect.  I think all the power utilities should be aware of this problem.  I’m an engineer not an electrician so if any terminology is wrong forgive me, but I thought it worth sharing!

That is the best conclusion possible. Your electrical installation should be well-protected for years to come, and the tripping problem has gone away. Thanks so much for sharing the outcome with us.

I’d just say that sadly this isn’t incontrovertible proof that it was the CU enclosure at fault. However, if that’s all that was changed (i.e. all the innards of the CU are still the same), it’s pretty compelling.

I should probably add that the neutral tail, of course, might not have been the critical issue; the point is that the RCBO was the only one immediately affected in the CU.  Changing it to match the other 5 unaffected ones cured the problem.  The CU is plastic as a matter of interest. 

Incidentally, another power utility had previously said they could not install a Smart Meter for me within my enclosure because it had to be a minimum 200mm from the CU.  Scottish Power’s installers thought different.