UK New smart meter, storage heaters now trip RCD

[Brian N]

I have just had a "smart" meter installed , and at night the electrics trips the RCD when the night storage radiator section comes on. I have had them out and they said installation was correct. I know a little about electrics (more over cautious and basic) but was suppressed when I looked at the lay out for the Night storage CU that the neutral goes through the RCD but the live goes direct - could this be a cause for the RCD to be triggered. I will have to get an electrician out to check all the wiring for the storage heaters if I cannot persuade them they have done something to suddenly make my electrics trip when that CU is on. Everything else seems to work fine. I have attached a simplified circuit diagram - electrics in the house have always been a little spaghetti junction, but never had any problems. Local electrician has always installed new stuff properly. Can anyone help? or suggest what my problem could be.

If I turn the CU for the night storage radiators off - then I get electrics 24/7 - if I turn that batch on then it pops overnight.

 

[Dartlec]

Very sensible comments, I ought to get someone in to take a fresh look at the setup at some point, although the installation of a smart meter has not helped. The original unit was looking old when we moved in some 30 years ago! We do have an earth rod, massive thing stuck into the ground. The other thing I did not mention was the "smart" meter does not work as it will not connect to their network (is it mobile phone?) so all this fuss and it is not reporting back to base - expect I will have to read this meter somehow for them!

So a not very-smart-meter, installed by a not-very-smart installer - excellent!

The earth rod may not be providing the only earth, but if it is, you may well need RCD protection on the storage heaters - or need to get the earthing upgraded by the DNO (who will sometimes do so for free).

It can be tested easily enough by someone with the right meter - may be worth finding a decent local electrician to just have a quick look over things - won't take very long to get a good idea of the installation and whether it's an issue or not...

But the meter installer should be coming back to resolve the issue they caused in this case anyway...

 

[snowhead]

So a not very-smart-meter, installed by a not-very-smart installer - excellent!

A.K.A,,Dumb and Dumber..

 

[timhoward]

It's funny how when working off photos you can have all the right questions and get the answers totally wrong....
I was thinking "Is it TT, and do you need an RCD for the off-peak CU". Yet managed to miss the (likely) TNS connection and thought the off-peak CU had an RCD because there's a similar CU in a picture which does have an RCD.....
I'm glad other people were on the ball!

 

[Brian N]

It's funny how when working off photos you can have all the right questions and get the answers totally wrong....
I was thinking "Is it TT, and do you need an RCD for the off-peak CU". Yet managed to miss the (likely) TNS connection and thought the off-peak CU had an RCD because there's a similar CU in a picture which does have an RCD.....
I'm glad other people were on the ball!

So does the live that goes to the storage heater CU need to go through the RCD - so instead or removing the neutral from going through the RCD - send both live and neutral through the RCD? I can see I need to get an electrician out after the meter installing team have finished.

 

[timhoward]

So does the live that goes to the storage heater CU need to go through the RCD - so instead or removing the neutral from going through the RCD - send both live and neutral through the RCD? I can see I need to get an electrician out after the meter installing team have finished.

Oh dear I've confused things even more....sorry....
1 - main things is that it has to work again, and splitting the N before the RCD is almost certainly how it was before, and this is how I'd put it back. Alternatively the L could be moved to other side of RCD. That works too.
2 - There's a secondary question of the earthing arrangements, if it's what we all think it is and what it looks like, there is no issue, and lack of RCD protection for storage heater CU is not the end of the world, just something that's advisable these days.
If on the other hand the earthing is really all from from the earth electrode then the lack of RCD protection would be a considerably bigger deal from a safety point of view.

I hope that clarifies things a bit! Basically let the meter people make it work again, and then best to get someone to check it over.

 

[littlespark]

Due to the age of the installation, i'd have someone in checking the RCD works for a start.... There are a lot of circuits coming off it as it stands, and adding the off peak CU through it too, could push it over the edge regarding cumulative earth leakage.

The "meter installers" have cocked this one up, and they need to fix it before you need to use the heating.

 

[timhoward]

Due to the age of the installation, i'd have someone in checking the RCD works for a start.... There are a lot of circuits coming off it as it stands, and adding the off peak CU through it too, could push it over the edge regarding cumulative earth leakage.

That's exactly why I'd favour splitting the Neutral, coupled with my natural self-preservation tendencies to touch as little as possible so I can't be blamed for the next problem ... ?

 

[snowhead]

The Off Peak Live (and Neutral) and and Normal Live (and Neutral) can't both go through the existing RCD.

Either the Off Peak Live and Neutral need to miss out the existing RCD, which is how they must have been before the Smarties turned up.
Or the Off Peak needs it's own new RCD.

 

[Brian N]

Oh dear I've confused things even more....sorry....
1 - main things is that it has to work again, and splitting the N before the RCD is almost certainly how it was before, and this is how I'd put it back. Alternatively the L could be moved to other side of RCD. That works too.
2 - There's a secondary question of the earthing arrangements, if it's what we all think it is and what it looks like, there is no issue, and lack of RCD protection for storage heater CU is not the end of the world, just something that's advisable these days.
If on the other hand the earthing is really all from from the earth electrode then the lack of RCD protection would be a considerably bigger deal from a safety point of view.

I hope that clarifies things a bit! Basically let the meter people make it work again, and then best to get someone to check it over.

Makes things very clear - and the need to get someone who knows what they are doing in once the meter fitters have done their job even clearer.

 

[Brian N]

From all the comments
My thoughts are to try to get them to take the live and neutral (neutral coming from a split) direct to the Storage radiator CU. To have normal main and neutral split - so one lot goes direct to the newer CU (one with internal RCD) and another lot going via the external RCD to the old CU. Then presumably I need a proper electrician to come and check it all over - with a view to putting in a RCD for the storage radiators.

I feel I may need to draw them a diagram and maybe put string on to explain where things go - LOL

 

[GBDamo]

These not so smart smart meter installers clearly are not trained to install on anything but the simple jobs and also work to the if you don't know ask principle
I wonder how many smart meters are actually installed where there are issues with the DNO equipment like main earths missing that are never addressed, the installation of smart meters would have been a good opportunity to get an overall assessment of the state of the installed distribution throughout the UK but the quality of the installers means it isn't going to happen

They don't want to KNOW what they already suspect so they send out these "installers" as they are not going to raise too many issues.

 

[telectrix]

get a sparks to put the meter mong's work back right so it all works. then decide on the way forward.

 

[brianmoooore]

get a sparks to put the meter mong's work back right so it all works. then decide on the way forward.

And tell said sparks to send the bill to the meter installers?

 

[Brian N]

Thought I would update you on this. They have been out and rewired the storage heater CU - did take me having to stop the chap and telling him what to do - he then had to contact his manager to get permission to do the wiring. But I think he understood why it was tripping by the time I had gone through how a RCD worked and that they had miswired my CU. I have had a chat with a friend of mine who is an electrician and he tells me it is unusual to wire the CU for storage radiators through an RCD. He agreed that the main CU is fine but that he needs to move the wiring to the CU that has an RCD as it is more likely to trip and on minor bits rather than what it is built to pop on. I agreed to drop my case with the electric lot for £450 compensation - and I will pay to have the wires moved. So end of this saga! Thank you all for your comments - I think without them I could still be battling the electric company.

 

[snowhead]

Thanks for the update, hope all is (going to be) working O.K now.