RTS Meter Replacement - 4 or 5-Terminal Smart Meter?

TCA

My parents have a single Horstmann Series K RTS meter (type K220G13) on a 2 MPAN setup with storage heaters, formerly Scottish Power Comfort Plus, now with Octopus.

One MPAN runs the entire house on Economy 7, including hot water cylinder but excluding storage heaters, which are on the other MPAN and for some reason, after switching supplier, could only be at the standard variable rate. There are no timers on the storage heaters.

With the imminent RTS switch off, a smart meter installation has been booked. Octopus are saying the storage heaters MPAN will be de-energised and a 4-port smart meter installed, whereas from all my reading I thought it would be a 5-terminal smart meter.

They told me that a time switch is integrated within the 4-port meter itself which would manage the switching on and off of the storage heaters during the off-peak hours, so a 5th port wasn't needed. From another forum I'm told this may be an overly complicated solution involving a HCALCS and a henley block, but this is over my head.

Can anyone please confirm what the new meter should be?

QrizB

TCA said:

Can anyone please confirm what the new meter should be?

Either 4-port with an external contactor for the E7 switched loads, or 5-port with an internal contactor.

The two arrangements are functionally equivalent. 5-port is slightly neater but no-one really treats their electricity meter board as an architectural feature or art installation, do they!

TCA

QrizB said:

TCA said:

Can anyone please confirm what the new meter should be?

Either 4-port with an external contactor for the E7 switched loads, or 5-port with an internal contactor.

The two arrangements are functionally equivalent. 5-port is slightly neater but no-one really treats their electricity meter board as an architectural feature or art installation, do they!

Thanks @QrizB. What should happen with the second MPAN in both of these scenarios?   

QrizB

TCA said:

QrizB said:

TCA said:

Can anyone please confirm what the new meter should be?

Either 4-port with an external contactor for the E7 switched loads, or 5-port with an internal contactor.

The two arrangements are functionally equivalent. 5-port is slightly neater but no-one really treats their electricity meter board as an architectural feature or art installation, do they!

Thanks @QrizB. What should happen with the second MPAN in both of these scenarios?   

I'd expect one MPAN to be closed down, with the smart meter being recorded against the remaining one.

TCA

QrizB said:

TCA said:

QrizB said:

TCA said:

Can anyone please confirm what the new meter should be?

Either 4-port with an external contactor for the E7 switched loads, or 5-port with an internal contactor.

The two arrangements are functionally equivalent. 5-port is slightly neater but no-one really treats their electricity meter board as an architectural feature or art installation, do they!

Thanks @QrizB. What should happen with the second MPAN in both of these scenarios?   

I'd expect one MPAN to be closed down, with the smart meter being recorded against the remaining one.

Great, thanks again. 

Is a 4-port meter with an external contactor different to a bog standard smart meter installed for someone with no related meters/2 MPAN set up?

QrizB

TCA said:

Is a 4-port meter with an external contactor different to a bog standard smart meter installed for someone with no related meters/2 MPAN set up?

Both configurations (4- or 5-port) are identical to those used for a single-MPAN E7 setup, which is what you'll have once the swap is complete.

TCA

QrizB said:

TCA said:

Is a 4-port meter with an external contactor different to a bog standard smart meter installed for someone with no related meters/2 MPAN set up?

Both configurations (4- or 5-port) are identical to those used for a single-MPAN E7 setup, which is what you'll have once the swap is complete.

I maybe didn't phrase that properly. Does the 4-port configuration you've described (which is presumably what Octopus intend for my parents) use the same smart meter unit I have in my house, as a non E7 customer?

I want to be 100% sure the engineer arrives with the correct meter, so would be good to know in advance if this is a non standard product.

Scot_39

TCA said:

QrizB said:

TCA said:

QrizB said:

TCA said:

Can anyone please confirm what the new meter should be?

Either 4-port with an external contactor for the E7 switched loads, or 5-port with an internal contactor.

The two arrangements are functionally equivalent. 5-port is slightly neater but no-one really treats their electricity meter board as an architectural feature or art installation, do they!

Thanks @QrizB. What should happen with the second MPAN in both of these scenarios?   

I'd expect one MPAN to be closed down, with the smart meter being recorded against the remaining one.

Great, thanks again. 

Is a 4-port meter with an external contactor different to a bog standard smart meter installed for someone with no related meters/2 MPAN set up?

Suppliers were not forced to offer complex metering support with bespoke tariffs - they were however forced in many cases - to allow single rate billing to be applied to them.  Which might explain why the second meter has gone flat rate.  And it seems unfortunate - and if high heat users - how much extra the current set-up has cost them over the years.

As to new meter

You sound like they have a restricted (only active for certain time during the day) feed from RTS to their storage heaters.

And so you ideally need a smets2 meter with ALCS support - my guess replacing existing non RTS for normal circuits - and restricted output - from either 5th port of 5 port or controlled auxiliary contactor - dirving the RTS meter tail.

It strikes me Octopus need to be and are very aware you have restricted circuits - it very unlikely that Octopus would ever somehow be leaving you / your parents without a switched supply for the NSH.

As in your opening post

"They told me that a time switch is integrated within the 4-port meter itself which would manage the switching on and off of the storage heaters during the off-peak hours, so a 5th port wasn't needed"

That timed switch - is something called ALCS - Auxiliary Load Control Switch - in meter jargon.

But worryingly not fully integrated in a 4 port meter.

And Octopus appear to be aware they do need ALCS.

And also aware they need to correct both MPANs in the national database.

So everything sounds very reassuring.

[ But just as note of caution

The problem is that ALCS needs hardware and software support - and not every 4 port model has it. Like the Aclara SGM1411 at the simple end of their 1400 series.  No company or meter fitter would ever I hope fit one - once saw the set-up.

So in theory yes - they can be physically different - a 4 port smart meter doesn't have to have any form of ALCS in it's hardware. But will still be capable of implementing an economy 7 tariff.  And many newer homes - flats I looked at with / for a niece over 12 months ago -  are wired without a restricted circuit - relying on device timers to align with meter off-peak.]

It makes no practical difference to you or your parents as users - or the tariffs the meter can support - if thats 4 port plus external 100A auxiliary contactor (switch) - like my smart meter - or 5 port with onboard auxiliary contactor (like the digital meter that was the firts replacement for my dual meter - ne RTS set-up) - its the ALCS facility and it's configuration that is important.

My meter drives a box like this - rather than having the switching on board

https://proteusswitchgear.com/products/100-a-heating-contactor-single-phase/

So you might end up with something similar being connected to the NSH tail currently connected to RTS for the NSH circuits.

If your lucky the fitter might install some isolator switches - EOn did for me without prompting.

QrizB

TCA said:

QrizB said:

TCA said:

Is a 4-port meter with an external contactor different to a bog standard smart meter installed for someone with no related meters/2 MPAN set up?

Both configurations (4- or 5-port) are identical to those used for a single-MPAN E7 setup, which is what you'll have once the swap is complete.

I maybe didn't phrase that properly. Does the 4-port configuration you've described (which is presumably what Octopus intend for my parents) use the same smart meter unit I have in my house, as a non E7 customer?

Scot_39 has given a full answer, but to address this point in particular:

There are different models of 4-port smart meter. Some include a switched output that can be sed to control an external contactor, some don't. It's entirely possible that the one in your house is capable of this, even though that function isn't used.

So long as the meter installer knows that they are installing an E7 meter with meter-switched circuits (for the storage heaters), they will arrive with the correct meter. And if by some chance they arrive with the wrong type of meter, it should be immediately obvious to them that they need the other type. But, as Scot_39 says, you might want to confirm that Octopus know this beforehand to avoid any chance of a wasted visit.

Phones4Chris

@TCA I would be inclined to go back to Octopus and tell them that you/your parents want a 5-port/terminal smart meter because of the storage heating. Whilst the resultant functionality has been explained and is similar, you really don't want the additional complexity (and space occupied by an HCALCS, it could result in restricted space problems in the future if you need other upgraded switchgear or consumer units)) and this also includes the additional vulnerability of  wireless control by the HAN, or even a similar installation to Scot_39.
(I am assuming that the RTS is close to the current meter and storage heater consumer unit).

Presumably your parents are on the Priority Services Register (pensionable age) which is a further consideration for having the least complex and most reliable system. Do NOT let them tell you otherwise. Additional equipment/complexity and wireless control reduce reliability, that is fact!
If you have trouble with any agent giving you bull over HCALCS nonsense or an additional contactor, tell them you want to speak to their specialist smart meter team, and end up getting it confirmed in writing/email that they will supply a 5-port meter.

As far as the two MPANs are concerned, one will be decommissioned which is what happen with my complex metering when I moved to a 5 terminal smart meter and has also happened with others in similar situations.

TCA

Many thanks to @Scot_39, @QrizB and @Phones4Chris for the detailed replies above.

As suggested by Chris, the best course of action would be to tell Octopus we want a 5-port smart meter. My parents are in their 80s but not on the Priority Services Register, so I'll mention this too.