A new smart meter is tripping RCD for 7 hours every night & I have a theory

[fearny26]

Hi guys I have this problem that I've been trying to figure out all week.

On friday I had a 5 tail economy 7 smart meter installed and every night at 2 am the RCD trips and you cant reset it until 9 am so the problem is obviously to do with the off peak supply coming on. Theres only 1 rcd for the whole circuit (i know, its an old setup) and 2 wylex fuseboards for on peak and off peak.

Now i was sure it had to be a problem with the meter setup because Ive never had faults before and I had the RCD tested on monday and thats fine. The energy company say its a problem at my end so I checked the EICR from 2018 and i saw that they didnt check the off peak board because i guess they were there in the day. So I figure maybe theres a fault on the off peak board then but why has it only shown up now? The board has been on but ive never used the storage heaters so its usually switched off at the board although I've never used any of the circuits I assumed the board functioned as the RCD had never tripped.

So, when they replaced the electric meter they also removed these old heating contactors that switched on the off peak supply and now all the meter tails come directly from the meter to the henley block and then to the RCD and fuseboards.

So my theory is that in fact both the off peak board and the heating contactor switch were faulty and so the off peak board was never live and thus the fault not detected, but with the new meter and the contactor removed the off peak board is receiving power for the first time and the fault is now present and trips the RCD for the 7 hours each night.

For reference the on peak board supplies everything in the flat bar the storage heater which I have never actually used.

There is nothing in the property switching on at that time and the off peak board is in fact switched off at the breaker, I've also tried unplugging and switching every isolator but the fault remains so I believe the faulty board could still be capable of tripping the RCD

I moved to the flat 11 months ago and had no problems previously whatsoever

I am sorry if its not explained well this is my first property and I am learning about all this for the first time and I'm just looking for some help because I'm having no power each night for a week now and the energy company cannot/will not help so any answers on here Im grateful for

I've attached a photo of the two wylex fuseboards and the RCD and henley block. Also are the old and new meters, my meter is top right with 2 tails going straight in and 2 feeding the old heating contactor that I think was broken in the bottom right

Thanks
Jake

 

[pc1966]

The whole setup looks a bit disturbingly complex, and there seems to be more than one meter-set?

Hopefully the spark who visits can do a bit more systematic testing than we can guess from the photos.

 

[snowhead]

Got it.

The Live to the Off Peak Consumer unit was sourced via the RCD.
Now it isn't.
But the Neutral still is.

There must be a small L to N leakage in the Off Peak C.U, enough to off balance the RCD.
And it will be on the Live side of the Main Switch

 

[fearny26]

Got it.

The Live to the Off Peak Consumer unit was sourced via the RCD.
Now it isn't.
But the Neutral still is.

There must be a small L to N leakage in the Off Peak C.U, enough to off balance the RCD.
And it will be on the Live side of the Main Switch

Thanks so much for taking the time
Great work ill mention it to the spark when he comes over. I assume it would just mean replacing the fuse board then.


I'm really keen to use this as a learning exercise for myself I think I understand you're explanation but would you mind at all going over why this problem didn't happen before the meter exchange and what it is that's changed to bring about this problem. Sorry if its obvious

 

[Rockingit]

"Theres only 1 rcd for the whole circuit (i know, its an old setup) and 2 wylex fuseboards for on peak and off peak."
Source URL: A new smart meter is tripping RCD for 7 hours every night & I have a theory - https://www.electriciansforums.net/threads/a-new-smart-meter-is-tripping-rcd-for-7-hours-every-night-i-have-a-theory.189919/

Unless I'm being thick and missing something already covered, how can you have a single RCD covering two lines of supply?! In order for that to be it would have to be upstream of the meter, which it never would be unless the meter fitter had been smoking something herbal at the time.

 

[snowhead]

Unless I'm being thick and missing something already covered, how can you have a single RCD covering two lines of supply?! In order for that to be it would have to be upstream of the meter, which it never would be unless the meter fitter had been smoking something herbal at the time.

On the original setup the meter only had a Single L & N out to the C.Us
This went direct to the RCD, through it then to the Henley where it split.
1 L & N supply to the Main C.U
Another Live went out to the contactor by the meter and came back in off the switched side to the Off peak Consumer unit.
The L to the Off peak now comes from the meter and misses the RCD, but the Neutral doesn't

 

[fearny26]

"Theres only 1 rcd for the whole circuit (i know, its an old setup) and 2 wylex fuseboards for on peak and off peak."
Source URL: A new smart meter is tripping RCD for 7 hours every night & I have a theory - https://www.electriciansforums.net/threads/a-new-smart-meter-is-tripping-rcd-for-7-hours-every-night-i-have-a-theory.189919/

Unless I'm being thick and missing something already covered, how can you have a single RCD covering two lines of supply?! In order for that to be it would have to be upstream of the meter, which it never would be unless the meter fitter had been smoking something herbal at the time.

Yeah I wasn't sure if it covered both boards or not as my knowledge is limited.
Is it possible to do so by using the henley block or is it the case that the RCD just covers the on peak fuse board?
[automerge]1598697623[/automerge]

On the original setup the meter only had a Single L & N out to the C.Us
This went direct to the RCD, through it then to the Henley where it split.
1 L & N supply to the Main C.U
Another Live went out to the contactor by the meter and came back in off the switched side to the Off peak Consumer unit.
The L to the Off peak now comes from the meter and misses the RCD, but the Neutral doesn't

Yeah I think I get it, basically with the new meter tails configuration it has circumvented the RCD so that when the off peak board energises the rcd only gets half the picture and trips. Do you think this means my equipment is not faulty and I just need to have the RCD reconfigured on the circuit to work with the new arrangement then

 

[James]

this looks like a borrowed neutral or one connected to the wrong board.
you need someone who is experienced at fault finding.

 

[Rockingit]

Gotcha. That's proper muppetry!

On the original setup the meter only had a Single L & N out to the C.Us
This went direct to the RCD, through it then to the Henley where it split.
1 L & N supply to the Main C.U
Another Live went out to the contactor by the meter and came back in off the switched side to the Off peak Consumer unit.
The L to the Off peak now comes from the meter and misses the RCD, but the Neutral doesn't

 

[snowhead]

Gotcha. That's proper muppetry!

If the meter and cutout were next to the Consumer units it would be fairly easy to see the problem.
I was immediately suspicious when I saw the Tail parked in a Henley at the meter.
At first I thought the meter person may have picked the wrong one off the contactor and was feeding a non RCD live onto the already live Henly near the C.Us

 

[fearny26]

Gotcha. That's proper muppetry!

Gotcha. That's proper muppetry!

Should the meter guy have checked before he changed it do you think or was it done wrong in the first place?

 

[fearny26]

Hi guys I finally got some sparks out from the company that carried out my previous EICR and to confirm yes some proper muppetry had been carried out by the meter man. Below is the report they gave me hope it makes sense

Attended site as requested by customer
He explained to the RCD trips when the economy 7 kicks in
Carried out relevant test and found that the main switch RCD (TT) had been double fed and feeding back to off peak, this is a very dangerous situation due to the fact that when isolated it has 200 volts due to only the neutral been switch off and risk of electrocution
Also found economy 7 board wasn't even connect and left in 100a Henry block - disconnect the off peak supply wrongly install by smart meter installer and put back the correct cable for the off peak.
All tests passed the required standard to BS 7671.


My understanding was that he had fed the tails wrong into the henley block tbh I think he probably didn't even bother to check. The sparkies didn't take long to figure it out as the consumer unit is only the other side of the meter cupboard so visually is easy to see and all they had to do was re jig the tails and remove one and hey presto everything's fixed! They also tested all circuitry and everything was golden which was ace.

Now my next move is to go back to the supplier with the ombudsman's support and kick some arse hopefully but most importantly get them to pay for the invoice

Thanks everyone on here for the helpful responses

 

[littlespark]

Result.

I don’t want to be disparaging about meter installers, but I think if there’s “only 4 cables” 2 in, 2 out.... then they got it easy.

add in a second board, off peak, and a time clock/ teleswitch and they are completely lost.

 

[LewisM]

In a situation like this could you pass on your costs and hassle to the meter company as their people have messed it up

 

[fearny26]

In a situation like this could you pass on your costs and hassle to the meter company as their people have messed it up

The ombudsman have said yes to this but I'm expecting them to try their best to wriggle out of it somehow

 

[richy3333]

Dont agree with the comment about the neutral. We have loads of THTC or economy 7 stuff up here and the neutrals are marshalled together in a Henley block.

If the RCD can’t be reset for 7 hours The issue has to surely be connected to the off peak supply in some way if that is switching on/off at these times?