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Discuss DNO Witnessing commissioning of a G59/2 Installation 50kW in the Solar PV Forum area at

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  1. FIT-PV

    FIT-PV Regular EF Member

    Just about to Install a 50kW system. The DNO have asked to witness the commissioning of the system.

    Can someone give me an idea of what they would expect on the day?
  2. pvman

    pvman Electrician's Arms

    If you have applied under G59/2 expect them to check the warning stickers are in the right place and check the system shuts down when the power is cut. All in all not much for £750!

  3. Princesolar

    Princesolar EF Member

    The DNO can ask you to carry out any test they wish for instance.

    Under and over Frequency
    Under and over voltage
    Loss of mains
    Vector shift

    If you have not carried out any testing previously or you do not have the test equipment, I would recommend getting a consultant to carry out the testing for you. Hope this helps
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  4. SibertSolar

    SibertSolar Solar Guru

    Business Name:
    Sibert Solar
    Can strongly recommend SolarTest for on-site commissioning assistance, they're very well known by all the DNOs and senior assessors around the country. Most 3rd party testing houses charge around £500 for on-site commissioning and take around 4hrs on average apparently. The test equipment itself can cost around £11K to buy if you were to do it yourselves. I'm not 100% au fait with the exact nature of the tests but I'm sure Princesolar has it pretty much covered in his post above.
  5. JD6400

    JD6400 Forum Mentor

    It is not something you can do yourself without that very expensive test kit !
    We used to use a company from the reading area for the G59 relays and testing when needed , their blokes were mostly South Africans and were worth the money just for the stories of home, alone !!!
    Who's your DNO , as we found that if you could provide proof of G59/2 compliance for the inverters then that was enough to keep them at bay ?
  6. paul7680

    paul7680 Guest

    I can recommend a company called DEIF (UK). They're a large company that specialise in power geneation controls and have a G59/2 protection relay in there product range. They also sell a "ready built" G59/2 Protection Panel that you can install easily in many locations. They have experienced test engineers that will perform a witness test anywhere in the UK and as they produce the relays, they have great product knowledge. Have a look at
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