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My Inverter Keeps Tripping or Reducing Power On Over-voltage. What can I do?




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    Or you could purchase a voltage optimisation device for your home like those SolarIQ things

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    Finn Peacock

    Yes - I'm getting a SolarIQ to trial next week. Stay tuned!

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    David Smith

    This is a really useful article.  When you say that your solar provider is required to provide you with the voltage rise calculations, can you tell me where this obligation is written down (I live in NSW).  I am having trouble getting this information from my provider.  Thanks.


    Reply from Finn:

    It is AS4777.1:2016 Section 3.3.3:

    "All existing and new cabling shall be designed and checked for the maximum voltage rise between the electricity distributor’s point of supply and the inverter a.c. terminals (grid-interactive port) in accordance with the following requirements. The overall voltage rise from the point of supply to the inverter a.c. terminals (grid-interactive port) shall not exceed 2% of the nominal voltage at the point of supply. The value of the current used for the calculation of voltage rise shall be the rated current of the IES. All IES within the electrical installation shall be considered."

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    Phill Kelley

    Hi Finn,

    This article (and many others on this topic) refer to a "Point of Common Coupling (PCC)" without ever giving an actual definition of what that means.

    In my case (and I assume in most householders' cases) the inverter has a dedicated cable connecting it to the house circuit-breaker board, and then there is a somewhat thicker cable (80A, I believe) connecting the house circuit-breaker board to the DNSP meter box.

    Is the "Point of Common Coupling" the circuit-breaker board or the DNSP meter box?

    The logic of the words in the phrase suggests that the PCC is where the energy from the solar system first comes in contact with the energy from the grid, so that would be the circuit-breaker board. However, I thought I would ask the question in case the answer turns out to be "the meter box" or "both" or "it depends".


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    Finn Peacock

    Great Question. You have made me realise that, according to AS4777.1:2016 I should have used the term "Connection Point" instead of "Point of Common Coupling". So I have updated the post to suit.

    "Point Of Common Coupling" (PCC) definition and "Connection Point" definitions (from NSW connection rules):

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