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Maximum size of solar panels

Kelly Marie Angel
I was just wondering if it's still the case that solar panel installations are rated to  16 amps  single phase does this apply to all single phase generators on domestic installations
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    As far as I know the 16A per phase limit (for G83 as was, G98 now) is for all small scale embedded generation, not just PV.


    You're not forced to use the G83/G98 approach though - you can generate/export more than that, but you'd have to use G59 as was, G99 now - which doesn't have the 16A limit but requires a much more complicated (expensive) approach.


      - Andy.
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    Hello Kelly


    That was never really ever the case. The Feed in tariff was less for systems over 4kW which equated to 16A and you need to ask the DNO if you want to connect more than 16A on single phase. In the past it was unlikely that more than 4kW would be cost effective but now maybe it's worth doing the sums, if there is enough roof space.


    Dave
  • 0
    In general, yes.

    It is in theory possible to get permission for a larger array, but the requirements are complex and such installations are very rare.

    AFAIK, the limit is 16 amps per phase, so 3 installations are permitted on a three phase supply., or two on split phase.
  • 0
    Just to be clear, that's 4kWp that is peak maximum generating capacity.  In practice in the UK for a domestic installation you will be lucky to get as much as 3kW actual around mid-day on a mid summer sunny day for solar.


    David
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    Dreckly:

    . . . That was never really ever the case. The Feed in tariff was less for systems over 4kW which equated to 16A and you need to ask the DNO if you want to connect more than 16A on single phase. . . 




    Actually, that has always been the case. The standard “off the shelf” solar systems, wind turbines etc were made to G.83 (now G.98) and were limited to a maximum installed capacity of 16A per phase per property. You may be able to install more, but that would usually by down to a network study by the DNO and full compliance with G.99, which is a lot more onerous (and expensive), and may often need bespoke servings calculating and testing. 


    Regards,


    Alan. 

  • 0
    Thank you Alan


    I knew that more than 16A required a network study by the DNO but I wasn't aware of the need to comply with G.99.


    Dave
  • 0
    Thankyou for your replies there's a lot more to it than I thought  part of the reason for asking is that in a YouTube video a man in Ukraine installed a solar farm in his field it seems to be rated about 10 kilowatts this got me thinking about it all. Don't think il be installing one anytime soon way to expensive
  • 0

    davidwalker2:

    Just to be clear, that's 4kWp that is peak maximum generating capacity.  In practice in the UK for a domestic installation you will be lucky to get as much as 3kW actual around mid-day on a mid summer sunny day for solar.


    David




    My understanding is that the PV modules CAN have a total output in excess of the 4Kw limit, PROVIDED THAT the grid tie inverter is so designed or programmed that it can not put more than the 4Kw limit back into the grid.

    It can be worthwhile to use a PV array in excess of 4Kw, despite the fact that under optimum conditions, that some of the capacity will be unused.

  • 0

     



    My understanding is that the PV modules CAN have a total output in excess of the 4Kw limit, PROVIDED THAT the grid tie inverter is so designed or programmed that it can not put more than the 4Kw limit back into the grid.

    It can be worthwhile to use a PV array in excess of 4Kw, despite the fact that under optimum conditions, that some of the capacity will be unused.



    I  am not sure how that would affect the regulations and in particular the FIT payments, where you have to declare the installed kWp value.  I suspect they know when your output is higher than the expected value for the installed capacity.  When I have had a particularly good period the meter reader turned up!


    David
  • 0
    Note that G98 doesn't have a 4kW limit - it has a 16A/phase limit which it describes as corresponding to 3.68 kilowatts (kW) on a single-phase supply and 11.04 kW on a three-phase supply.

      - Andy.

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