Wiring 2 Consumer Units to a Smart Meter

stacer · Aug 13, 2023

I live in a flat in Scotland supplied with an old 2 meter system called THTC where one meter using a time signal supplied heating and hot water etc and the other the remaining circuits ie lighting and sockets etc. The flat was professionally rewired about 2 years ago and although there is no longer any timed heating (storage heaters etc) both meters remained in situ with new consumer units wired to each meter. These meters are now charged at a single rate but because of this system no other energy supplier will take it on and it is impossible to shop around.

Out of the blue, my supplier has booked me in for a smart meter installation on Tuesday which will be great but I am concerned that the installer may refuse to install both consumer units to the same meter. The consumer units and meters are co-located in the same cupboard and connected to the same incoming supply.

Is it simply a case of removing the old meters replacing with the smart meter and connecting both consumer units to the meter?

littlespark · Aug 13, 2023

That was Scottish Power’s Total Heating Total Control but if it’s all single rate now, there shouldn’t be an issue… in fact, I would think the meter installers have come across it before.

Can you post a photo of the set up just now?
(may need to edit photo to reduce size)

What is supplied on the heating board if you don’t have storage heaters?

An electrician could rewire the tails through a “Henley” block… basically splitting the supply from one meter into both boards… and making the other tails safe for later removal by the meter engineers.
(First part of postcard, or general area of Scotland? There are members on here that could visit and give a few options)

You don’t have to take your suppliers offer of a smart meter, not really.

stacer · Aug 13, 2023

littlespark said:
That was Scottish Power’s Total Heating Total Control but if it’s all single rate now, there shouldn’t be an issue… in fact, I would think the meter installers have come across it before.

Can you post a photo of the set up just now?
(may need to edit photo to reduce size)

What is supplied on the heating board if you don’t have storage heaters?

An electrician could rewire the tails through a “Henley” block… basically splitting the supply from one meter into both boards… and making the other tails safe for later removal by the meter engineers.
(First part of postcard, or general area of Scotland? There are members on here that could visit and give a few options)

You don’t have to take your suppliers offer of a smart meter, not really.

Thanks for getting back, firstly I am keen to get the smart meter as it frees me up from the SSE THTC system and allows me the freedom to shop around.
the heating board supplies a 10 litre water heater, shower, towel rail, reverse cycle a/c for heating (2x 2.5 KW units) & panel heaters.

The appointment is for Tuesday and living on an island it’s too late to get someone out to look and after trying for 18 months to get to this, I’m not going to delay while I get it looked at. The energy supplier knows what tariff I’m on so presumably knows that it’s a 2 meter system, I’m just being prepared for the installer to try and use an excuse not to do it. The whole thing is a major issue on the island trying to get smart meters installed and off this THTC system.

[ElectriciansForums.net] Wiring 2 Consumer Units to a Smart Meter

littlespark · Aug 13, 2023

I don’t think any of our members serve the islands… but I might be wrong.

As it’s a set appointment, you might not be able to get an electrician in time to do what I suggested.
Is there someone you can speak to at the supplier to see if the meter engineer would split the tails?

Speaking of which…. If those are metal boards. The tails shouldn’t be entering in 2 separate holes….. not sure how serious the effects could be, but technically against regulations.

I take it the earth wires enter the CU from behind? I see the main earth just goes through the wood board.

stacer · Aug 13, 2023

littlespark said:
I don’t think any of our members serve the islands… but I might be wrong.

As it’s a set appointment, you might not be able to get an electrician in time to do what I suggested.
Is there someone you can speak to at the supplier to see if the meter engineer would split the tails?

Speaking of which…. If those are metal boards. The tails shouldn’t be entering in 2 separate holes….. not sure how serious the effects could be, but technically against regulations.

I take it the earth wires enter the CU from behind? I see the main earth just goes through the wood board.

Yes, no chance of getting an electrician before the meter change. I’ll just have to hope that the engineer who will be very familiar with this system and who should know that I have 2 meters will have the means to make the connections etc.

I must assume that the earths enter the CUs from behind, without taking things apart there is no way of telling.

littlespark · Aug 13, 2023

I would hope the meter fitters do have the parts. It’s all stuff they should carry.

The problem is, a lot of them are not trained exceptionally well…. And if it’s not like what it shows in a book, they are completely lost.
I would hate for them to come, and walk away.

I was hoping that photo could be sent to them first to give them some idea of what to expect.

stacer · Aug 13, 2023

littlespark said:
I would hope the meter fitters do have the parts. It’s all stuff they should carry.

The problem is, a lot of them are not trained exceptionally well…. And if it’s not like what it shows in a book, they are completely lost.
I would hate for them to come, and walk away.

I was hoping that photo could be sent to them first to give them some idea of what to expect.

At this late stage no after 18 months of wrangling, I reckon it’s just best to wait until Tuesday and if it’s an issue I’ll get an electrician when I can and move forward from there, many thanks for your input