Hiya!

I think this is a bit of a tricky one @ruralCTsupply , I have to agree that you’ve got an unusual setup.

What I can confirm is that 3-Phase Smart Meters are capable of dealing with 2-Phase Supplies. That’s a piece of cake, as is all sorts of unusual and exotic setups. The only snag is that 100A capacity limit per-phase. Most Domestic suppliers don’t support AMR Meters either I’m afraid.

However… There may be options yet! I’m going to take this one backstage and ask for thoughts. We’ve got the ability to get expert opinions for something like this and I think I know one or two people who’d be absolutely perfect.

Bear with me though, as I need permission to get those people involved in this thread. I’m on it now and we’ll keep you posted!

Thanks for that - very much appreciated.  

In terms of a little more context I did recently hear back from the Business side of one of the Domestic suppliers who suggested they could supply a “RCAMY” meter for my supply which from my in expert digging around seems to be a bit like a slightly more sophisticated version of a standard AMR meter.  

But it is not yet clear to me whether a RCAMY meter would (a) allow me access to wider range of modern tariffs or (b) be something that the Domestic side of the supplier in question could pick up and offer to me a a domestic customer or whether i would have to convert (with all the downsides) to a Business one.  I have asked these questions to the Business supplier in question (waiting for a response), but from previous experience on this subject with this supplier I have low expectations about what I might get as a response..

So is the A1140 you have rated 200a.

I thought it was 100a when I read the documentation.

I suspect i have misunderstood the documentation... 

https://www.camax.co.uk/product/elster-a1140-mid-polyphase-phase-electricity-meter

I am not an expert but when Direct Connected the tech docs seem to suggest it is up to 100A per phase, but when CT connected (which i believe it is in this case) i think it might be more.  

Attached picture is the meter in question, and also a picture of the incoming supply (labeled by a DNO engineer who measured the currents).

seems only 1 picture uploaded.  here is the meter

looks like you can set the “CT ratio” so the meter can handle bigger currents.  

https://www.metermarket.co.uk/product/elster-a1140

the “Ct Ratio” drop down has an option for a “200/5A” option, which is what my meter is set at.

@ruralCTsupply perhaps a silly question, I assume you are sure you need 200a per phase. 

Are there 200a fuses on each of the phases. 

not a silly question, have investigated downgrading the supply to 100A per phase but is a large property with a number different demands and the electricians who have looked at the load balancing have advised against it.  similarly switching to a 3 phase 100A per phase supply is also not really an option either as, while this could possible provide enough current, due to our location the DNO indication for how much this might cost was a serious 6 figure number with the caveat that being able to deliver it was highly uncertain due to various local environmental challenges of installing the necessary 3rd wire.

@ruralCTsupply

Best wait for @Blastoise186 then to see if he discovers any options.

The reality is Octopus Energy have the vast majority of time of use type tariff at the moment so you may be best directing the question at them in case what works for OVO won't work for Octopus, or if they have any solutions. 

Other suggestions are messy. I am not sure they are realistic, and you may already have considered them. For example 

A left field idea is to investigate the use of battery storage so you shift your energy use and dramatically reduce your peak load down to 100a per circuit. Also this could store some but perhaps not all the excess PV. 

Another is possibly have two separate meters if one could be 100a and one 200a and have a ToU tariff on the 100a meter. Again messy and you have the issue of standing charges and it is still not giving you ToU over all your energy. Am not sure this idea is realistic and may not work with your usage anyway 

I am sure you have considered lots of things reading your posts.

The ultimate challenge is that suppliers won't be looking to offer solutions for what will be a very small number of domestic customers i suspect. I fear no supplier will offer a domestic solution so you won't ever be able to access any domestic time of use tariffs without 

1. Getting the peak load down

2. Going to the expense of getting that 3rd phase installed. 

Have you had your actual peak load measured in real-time? I just wonder how high it is as that would help inform possible solutions perhaps? Comparing it to the theoretical maximum that has been calculated might be interesting?

I’m still looking into this myself. If I can get permission to call on some expert advice, that will likely make things easier.

But it’s a really weird edge case in that I’ve never heard of a Domestic supply having 200A per Phase before!

Oh, and I recommend against Dual-Meter or Twin-Element setups. They caused nightmares back in the day and just aren’t worth it anymore. I can definitely tell you that the Sekrit Smart Meter Friend doesn’t want to support that type of setup in the future.

Some fact checking here on AMR meters:

“We've several hundred AMR meters.. none of them 'talk' to a Domestic Supplier though.. that's not how they work.. they are communicated with by the AMR agent that then provides us the readings.”

I’ll share this topic with our secret weapon smart experts that blastoise refers to, and see if they can suggest anything. 

@Cumberland Lass @timciren are ground source heat pump forum members. Could you share your meter type to help out, @ruralCTsupply?

Hi again, @ruralCTsupply.

Some detail here from a colleague who is working on the smart platforms team: 

The polyphase meters we're starting to install are capped at 100amps per phase, but the amp rating isn't the issue here.. it's that the ONLY option, as they call out, is for them to have an automatic meter reader (AMR) meter installed with working communication (comms). There is no smart solution for CT, polyphase or otherwise. They were explicitly excluded due to the complexity of the way the energy is managed and measured. So suppliers are obliged to install an Advanced (AMR) meter for these sites.

It must be noted that the Elster A1140 IS an AMR capable meter already... it can have a comms module connected to it to provide remote readings to a supplier. But that means they cannot get access to any smart products or services. This, or a meter exchange for another AMR meter is the only options OVO could offer. 

Sorry for the basic question @Tim_OVO 

So does that mean OVO couldn't even fit a SMETS2 3 phase meter for this property even if they did manage to get the load down to 100a per phase? The amp rating isn't the issue?

I think that is what you are saying? 

Octopus is my current supplier and it is their Time Of Use tariffs i have been trying to access. Somewhat frustratingly i went through a lengthy discussion with them prior to getting the solar array about whether - if i got a PV array - would be able to access their solar export tariffs.  We discussed the nature of the meter and supply in some detail and they (eventually) confirmed if i was to get a solar array they would be able to provide a suitable meter to access their TOU tariffs.  This was welcome news as exporting via their Solar Tariffs made the project considerably more economically compelling that SEG or no export options.

So i went ahead health with planing permissions and DNO G98 permissions etc and paid for the array installation.  Planing and permission took 6 months (Planing Authorities we slow and DNO was slow), but eventually install happened in Nov last year.  I then went back to Octopus to deal with the meter upgrade and it seems they have now decided they can’t supply the meter they confirmed previously and is looking increasingly like they can’t provide any meter that would allow me access to their TOU or Solar Export tarifs.  This is quite frustrating - particularly from an economic point of view as not being able to sell excess pv power back via their solar tariffs is not small. 

Although I haven’t quite exhausted the conversations with them, as I am having trouble finding people there who can see the whole picture (i.e. the CT 200A supply and meter and tariff options in a Domestic context).  So possibly there might still be a plausible solution.

The helpful input on this forum makes me think there might not be an easy solution to the meter issue other than the Reduction in the Peak Load and adding a 3rd phase options.  

The other option for improving the economics is increasing self consumption somehow (adding batteries or converting some other steady demand energy source to electricity). Although this requires further upfront cost etc so is not a no-brainer.

The suggestion about actual realtime peak load measurement is also a good one.  I have a monitor installed where i track and store intra day power kWh energy use (down to minute by minute) across the 2 phases, but not for an Amp/current. I will see if i can find a suitable electrician who might be able to help with this, although night need a whole 12 months worth of monitoring to capture realistic profile across all seasons. 

Thanks for this.  The A1140 is AMR capable but our one up doesn't have the communications model attached (although I understand that could be added).  the specs indicate it can provide import and export measurements as well as Half Hourly Readings (or more).  The bit i haven’t been able to find out is if Ocotpus (or another supplier) could actually use this data transmission to provide access to Solar tariffs of Time Of Use tariffs.  I have been told by Octopus Business they only offer fixed 12m contracts, so possibly that is the case for all Business suppliers, and if so perhaps no supplier has systems set up to take HH AMR data for their TOU or export tariffs and are only set up to use the SMETS data.

I am not sure if there is an Advanced AMR meter (AAMR?) that suppliers are able to use to offer TOU and/or solar export tariffs that might be suitable, although given the supply size if it is a thing it sounds more like it would be on the Commercial side of things rather than Domestic. 

Octopus have suggested they could do a meter exchange to provide an RCAMR meter that could automatically provide monthly readings instead of a manual requirement but it would offer no other benefits in terms of access to a wider range of tariffs, so this makes little sense.  Also, given historical experience on this matter with Octopus I imagine something will come up if I did pursue this that meant they they couldn’t actually do it.

Thanks for this extra information, @ruralCTsupply - it’s a shame to hear you were given the impression a smart meter would be possible. @Jeffus that is correct, I’m told there is currently no smart solution for CT, polyphase or otherwise.

One thing though, it’s worth checking with your solar installers if you can get an export meter for your solar panels. @M.isterW has shared some great advice on a topic recently that explained that it would have to communicate every 30 minutes. But that would allow export of excess solar generation via the smart export guarantee.

@Tim_OVO

I am really showing my ignorance now…

What is the difference between "CT, polyphase or otherwise" and a regular 2 or 3 phase supply that can support a SMETS2 3 phase meter? 

One further question for the expertise of this forum is a bit more Out There.

Next to our main 200A split phase CT supply (literally 1 metre away) we have a second metered supply that is single phase 100A.  this second supply has separate mpan etc and is normal sized supply for normal small/medium sized residential property.  this supply DOES have a SMETS2 meter that happily transmits usage data to supplier over the SMETS2 WAN (via a connected T2 boosting aerial) and I can get access to all Octopus’s TOU tariffs for it.  The demand from this supply is v small, approx 9kWh per day in the winter and <2kWh per day in the spring/summer/autumn.

The Out There question is does anyone here have any idea whether it would be possible to add a diverter or manager some sort after my Solar Edge pv inverters that could send the electricity generated by the PV array to the main supply (as it does at present) when there was demand from the main supply and but when that demand had been satisfied could send any excess generated electricity back to the grid via the SMETS2 meter?

It sounds a bit whacky to me but if this was possible I could possibly self consume as much as possible via the Main CT supply and export the PV generated electricity via the SMETS2 meter?

@ruralCTsupply @Tim_OVO We have  GSHP and solar PV. I'm getting a bit lost with the techy chat in relation meters, but if it helps anyone here are photos of our meters.  

Ours isn't a particularly large set up. House is 4 bed semi.

Plenty of people dump excess Solar PV into immersion heaters to heat water, simple convector heaters, LiFePO4 electric batteries and heat batteries like  Sunamp etc.

Again plenty of people export stored energy in their LiFePO4 batteries.

So it is certainly an interesting idea. 

I think @ArundaleP might be able to answer this one…

@Jeffus according to auroro energy: 

CT (Current Transformer) meters are installed on any connections with a load greater than 100 Amps. They measure a fraction of the amps (current) passing through the connection and a multiplier is applied to this reading to reflect the actual amps.

@Tim_OVO so if @ruralCTsupply can get his load below 100a per phase they don't need one of these CT meters and can have one of OVOs regular 3 phase SMETS2 meters? 

If my understanding of that is correct… An example 200A of Peak Usage could be served quite easily by normal 3-Phase?

I thought that was how it worked, but i am no expert

I think @ruralCTsupply is going to try and get an electrician to  put  in some monitoring to see what the actual peak load is on the property which might help with options. Whether they have close to a peak 200a load for each of the current two phases. 

Your solar edge inverter should have settings that prioritise demand as you want;

1 - house (or specific feed if connected via)

2 - energy storage (if fitted)

3 - feed to grid

You would need to ensure that the DNO were ok with any extra grid feed if on a specific leg of the supply. Sounds like that’s already in place but worth checking

What would be difficult (can’t think of a way) would be to couple this across feeds