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Generator grounding?

    • 1 posts
    January 5, 2020 2:41 PM PST


    I bought a small single-phase generator. With this, the central heating (single-family house) is to be operated in the event of a winter power failure.

    A couple of PV modules with grid feed are already installed on my roof. Just in case, last summer I bought an island inverter with 2 180AH batteries. I can switch the PV panels from the grid inverter to the stand-alone inverter. Unfortunately, I had to find out that on cloudy days there is so little electricity coming in in winter that it cannot be used to operate heating.

    That's why I bought the generator. The off-grid inverter naturally has an input for 230V. Here you can either connect it directly to the grid or keep a generator connected. The boiler room hangs at the output of the inverter. I also installed a changeover switch with zero position (2-pin for N and L) so that I can switch the boiler room from the mains supply to the inverter.

    And now the question about grounding. The generator has an earth connection. I googled a little. In theory, I wouldn't have to connect the earth if only one device was connected. In my case, only the stand-alone inverter is connected. The boiler room has more consumers, but it depends on the inverter and not on the generator.
    On the other hand, it would have to be earthed if you connected the generator to the house. Now the line from the generator to the inverter also has a protective conductor - and the inverter is grounded.

    So does the generator have to be earthed again? And if so, how? Can I connect it to a grounded heating pipe or do I have to tap a cross earth in the garden?

    This post was edited by Josef Spalding at January 5, 2020 2:42 PM PST
    • 157 posts
    January 5, 2020 3:58 PM PST

    In most cases you would only need an equipment grounding conductor run with the feeders from the generator to the house