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mattwillhill
Rank 2
March 23, 2022
Solved

Are my solar PV panels connected to my smart meter and measuring my exports correctly?

  • March 23, 2022
  • 44 replies
  • 13155 views

We recently in Dec 2021 had a large PV solar install completed on our house.  A new 24 panel [385W each] Solar array at 8kW by a seemingly professional company. Disappointingly the install has issues, the main one being that the house utilty meter has the same consumption rate as before the solar install started!  This suggests there is wiring config. or equipment fault issue somewhere or the meter cannot cope with Solar supply since we are having large Solar Yields!

        Either way we are none the closer to getting either the solar installer coming back to fix it in a hurry [I don’t think they understand it!] or the Utility company to check  the meter!   All this in rapidly rising energy prices ….. pause to weep …… seriously this is cry for help please, we have spent a fortune for nothing! 

       One thing that stands out to me, being a lighting engineer [as a I have some electrical knowledge - although a little knowledge can be a dangerous thing!] is that the Solar Installer has wired the Solar Arrays Inverted 240V output not direct to our Consumer Board but has put it through our Utility Meter with the grid supply [on a single split combined cable]. When I asked the solar installers engineer how the Utility Meter can tell the difference between electricity we are consuming direct from the grid or through the Solar he just shrugged his shoulders and exclaimed that it just can! Personally rightly or wrongly i am unconvinced!

I attach an image of our electrical utilty meter [ a SMET 1 – Elster AS300P] cupboard with the solar installers wiring config  displayed. Please the question to those in the know is should the Solar always be through the consumer unit first [as in schematic A] or through the utilty meter [as in schematic B] shown , or does it depend on  other factors?

Any help or direction most welcome.

    Best answer by PeterR1947

    @mattwillhill  There is no way that meter will measure export as the PV is not connected through it.  If the PV was connected as every other one I have seen, i.e. though the consumer unit, your Elster meter would be able to measure the export.

     

    All meters are clever enough to sense which direction current is flowing through them.  With non-smart meters, if the very old variety the spinning wheel would go backwards, the electronic ones would display “RED” (Reverse Electricity Generated).

     

    A Smart meter is smart!  if you are exporting to the grid, this is sensed and measured as export which you now know how to read and when you are not exporting the meter measures the consumption.  When you are generating but less than the house is using, the meter will simply show the reduced rate so your monthly PV generation will reduce the consumption you are seeing at present.  On thinking further about what I said earlier, I don’t think a PV installer is allowed to connect directly to an incoming supply, only your DNO is allowed to make these connections, perhaps @Transparent  can confirm that

    44 replies

    Tim_OVO
    OVO Staff
    Tim_OVO
    OVO Forum Legend
    March 24, 2022

    A fantastic topic with all the information we could need (probably), nice one @mattwillhill.

     

    Let’s see if we can make some solar PV members aware of this topic. I’m sure some of them have previously discussed how their panels were connected to the property. 

     

    @sylm_2000 I forgot that you had solar! Also we have a former electrician knocking about who has solar PV in the form of @PeterR1947. @dnshorto did extensive research in how to use storage with their solar array. Are you able to advise how these eventually connect to the consumer unit and how Matt can track generation and export to work out why imports haven’t dropped?

    Carbon neutral - we need a community to get there! My green tech: Aclara SGM 1411-B smart meter, Chameleon IHD6
      G
      Newcomer
      Graham110011
      Newcomer
      March 24, 2022

      Hi - do you know how much you’re exporting? Your installer is correct, Smart meters can/should work out which way the current is flowing and calculate accordingly. It could be that you’re not consuming the power when it’s available so it’s being sent to the grid, then when the sun goes down, you’re using the oven (or the likes) which is keeping your grid usage the same as before. 

      Have you tried this:
       

      Honeywell Elster AS300P (SMETS1)

      To get an export reading from this smart meter:

      1. Press and hold the grey middle button until the main menu loads up
      2. ‘General’ should appear on-screen – press and hold the middle button again to select this option
      3. ‘Time & Date’ should be visible – now scroll with the bottom button until you see ‘TOU Registers’
      4. Press and hold the middle button once more will hovering over ‘TOU Registers’ and you should now see ‘Cum. Exp.’ with a value underneath it.
        P
        Rank 3
        philipH
        Rank 3
        March 24, 2022

        Our usage is interesting in that we sometime, or regularly on a sunny day, produce more kWh than we use but because our usage is in the morning and evening a huge amount of that produced kWh is going into grid so we still end up buying from the grid.  Greater battery backup seems to be the way forward (I think)

          PeterR1947
          Newcomer
          PeterR1947
          Newcomer
          March 24, 2022

          I have to say that every solar PV installation I have seen is connected from the inverter through a breaker switch (sometimes one in the loft and one downstairs) to the generation meter and then either through an existing MCB on the consumer unit or on an MCB on a  separately installed CU which is then connected in the same way as the existing CU, i.e. on the CU side of the house.

          I have searched for standards regarding PV installations and there is an IET standard but not available on line;I feel uncomfortable about PV connected directly to the incoming supply but can’t say it’s definitely wrong

          PeterR
            M.isterW
            Rank 6
            M.isterW
            Rank 6
            March 24, 2022

            I agree with @PeterR1947 . Your solar output should go into a CU then into the meter (option A in your diagram). It looks like yours has been wired up to allow current from the solar CU to the grid without going through the meter.

             

            Everything up to and including the meter belongs to the electricity company so if your electrician has fitted the connector (marked Join in your photo) then they've messed up big time. You should have one pair of unbroken cables from the fuse to the meter. Everything else should be on the house side of the meter.

            1992 4 bed detached house. Solar PV + battery, Zappi EV charger, Mitsubishi Ecodan ASHP and i-life2 fan assisted radiators.... No gas 😊
              Tim_OVO
              OVO Staff
              Tim_OVO
              OVO Forum Legend
              March 24, 2022

              As with everything involving cables, pipes and anything that goes bang, it’s best to combine first hand experience with getting a professional in to view things first hand. In this case @mattwillhill, a qualified electrician. 

               

              Keep us updated please! 

              Carbon neutral - we need a community to get there! My green tech: Aclara SGM 1411-B smart meter, Chameleon IHD6
                M
                Rank 2
                mattwillhillAuthor
                Rank 2
                March 24, 2022

                 

                Graham110011 

                Thank you Graham
                We really appreciate your input and we would like to thank you in advance. We were unaware of this "menu" function of the Honeywell Elster AS300P Utility Meter, so many thanks for that.  We have checked our export values, as recommended and our "Cummulative Export" is a BIG FAT "00.00" [zero] - see image. So not sure what to make of this accept something is not working! 

                We understood your analysis of explaining our usage but sadly it cannot be the reason.  Our average standby use is 650W/h = 15.6kWh/day regardless of day or night only during the day we have some laundry and in the evening from 6pm do we have other extras like Airfryer, cooking and TV which gets us closer to 22.6kWh/day.

                One thing that puzzles me about your comment about the Elster Utility Meter current flow is that surely if both grid and solar cables are joined as one before the meter then whether 'juice' is drawn from the grid or the solar, the meter will see it the same - the current flow is in the same direction through the meter on to the consumer board is it not?

                Since our solar installation on the 16/12/21 we have used according to the Elster Utilty Meter as of today [24/03/22], i.e. 97 days 2,190kWh or 22.58kWh per day. This is our normal consumption rate which prior to solar was for the year 2020/21 averaged out at 22.6kWh [ how uncanny is that!]. Our Solar Edge Inverter Meter reads that we have had a Cumm.Total Solar Yield of 1.29MWh or 1,290kWh so I should have more than halved our true electrical consumption!

                We should add to give you more of a full overview as follows;

                1. The system is 25 panel Hanwha Q-Cell BLK-Duo-380W with Solar Edge micro-inverters.

                2.  We have Solar Boost [Solar Immersion heating all our hot water needs - thankfully this is working 'A' OK].

                3.  We have a 7.2kWh battery storage on this system i.e 3 x 2.4kW US2000 Pylontech Lithium Ion.

                4. These are controlled by a Luxpower TEK monitor LXP 3600ACS module.

                    The batteries strangely do NOT seem to store and discharge on the default settings [another area under review] although I have been able to over-ride this  with enabled settings.Why this is we do not yet know but the LuxPower TEK monitor is also giving us inconsistent and incorrect data, like inflating our Total Consumption to justify both the Solar and the Grid Utility consumption. A classic tell tale sign for something beyond us, like adding our solar gain as actual usage or something similar !

                5. The installing engineer visited with us recently and on inspection has recommended that they upgrade to 2 x 6mm cable feeds instead of the 1 x 6mm cable feed they have to the Solar Panels as current.He is thinking over-current is an issue or similar to that effect? He also thinks that this may affect the CT sensors on the cable feedback.

                6. He seems to be at a loss about why the meter is NOT responding! Sadly this is my biggest worry!

                So yes, we are getting Solar Yields on some days in excess of our normal consumption to values like mid-40's kWh, so far today I have 35.4kWh and its only 3pm. So we should be filling those batteries and exporting some! Sadly with these complications and inconsistencies we are at a loss and we think these issues are inter related. Right now we would settle for sorting out our Utility Meter to stop charging us and start registering our export and Solar generation.

                One thing the Solar Installation industry appears poor at is a centralised standards body and resource, better liason with Energy Suppliers and an information resource. Its a nightmare for a consumer to appeal Suppliers and find information on correct installations, We would gladly pay someone to review our system.

                We are convinced our answer lies in our set up but we have read things online about SMET1 meters being incompatible and so on but its hard for us to know.

                What would you advise as a next move?

                Many Thanks for your input. 

                 

                  PeterR1947
                  Newcomer
                  PeterR1947Solved
                  Newcomer
                  March 24, 2022

                  @mattwillhill  There is no way that meter will measure export as the PV is not connected through it.  If the PV was connected as every other one I have seen, i.e. though the consumer unit, your Elster meter would be able to measure the export.

                   

                  All meters are clever enough to sense which direction current is flowing through them.  With non-smart meters, if the very old variety the spinning wheel would go backwards, the electronic ones would display “RED” (Reverse Electricity Generated).

                   

                  A Smart meter is smart!  if you are exporting to the grid, this is sensed and measured as export which you now know how to read and when you are not exporting the meter measures the consumption.  When you are generating but less than the house is using, the meter will simply show the reduced rate so your monthly PV generation will reduce the consumption you are seeing at present.  On thinking further about what I said earlier, I don’t think a PV installer is allowed to connect directly to an incoming supply, only your DNO is allowed to make these connections, perhaps @Transparent  can confirm that

                  PeterR
                    G
                    Newcomer
                    Graham110011
                    Newcomer
                    March 24, 2022

                    No problem. Ask a solar electrician (these guys are good: https://empowerenergy.co.uk) for a quote to investigate and fix the issue. It should be free as they’re just quoting and should be able to provide that via pictures. Send that to your original installer and insist on a fix within 10 days. They say no, you’ll still need to get it done. Then after biting your lip/tongue, go to citizens advice and they’ll tell you what the correct process is to a) get your money refunded and b) complain against their licence.

                     

                    just for the sake of it, you may want them to do a quick overall inspection just to be on the safe side 

                      M
                      Rank 2
                      mattwillhillAuthor
                      Rank 2
                      March 24, 2022

                      PeterR1947

                      M.isterW

                      Well prior to posting [and before Graham11001 response] I did think that all the flow diagrams I had seen always had the cabling from the Solar PV go straight to the Consumer Unit. In fact the installer told me before the install that they usually go to any spare MCB 'fuses 'on the Consumer Unit but as there wasn't any spare he said he would install a Mini DB. I think he choose  the exterior Electrical Meter cupboard for ease of access rather than the cupboard the DB is in. 
                             It had not crossed my mind until a very recent inspection that he would 'jump in' before the meter. In fact I asked him on his last visit why he didn't jump the other side of the meter [the Consumer Unit side] and he said he was trained to do to this way.  I highlighted the complication of the meter but he said the meter could cope with it and as I do not understand how Solar export's to the grid I assumed it was the reason why!

                      I do accept for other practices and professional standards. Its not like a I am trained qualified professional engineer myself. I think to get further forward I need to;

                      -  look for a reason why the meter keeps rolling,  

                      - then  wondering about the actual IET standards and any update to the 16th Edition Wiring Regulations for further clarification.

                      - ironing out the Luxpower TEK data

                      - getting the batteries running properly

                      At the moment I am stuck at ground zero! I have some great equipment and solar generation but no meaningful connection to my house and meter! I am quite happy to quit on my Solar PV company, get in a qualified engineer and get it wired correctly and bill this back in a small claims court but I have to reasonable and fair to the Solar PV installer first.
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