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Fixed diesel generator earthing

Hi folks, i'm after your knowledge again!


I have a 184KW diesel generator which is to supply a test bay for testing machines to big for the building supply.  The generated supply will not be used/connected to the building supply.

Would the earthing arrangements be as TT with a rod at the generator connected to the neutral/star connection?


Thanks in advance ?
  • You will find a 30mA RCD (or MCCB or whatever) a problem with the starting current unless the compressors are fairly small or have VFD starting. The compressors should be electrically tested in the normal way before connection, presumably with bolted connections. I suggest HO7RN-F cables for connection as singles, much easier to work with and very tough. 50mm2 singles should do you fine, with suitable lugs for connection to the compressors. An Isolator to prevent having to turn the generator off repeatedly would be good, as well as indicators to show when the cables are live, would be a sensible safety measure.


  • HSE leaflet  on Generators (No update ) but still relevant.


    ieeexplore.ieee.org/.../5317048


    Leaflet on Neutral inversion (No update) since 1936 (In your case original posters question  only for a read ) 

    Published in: Journal of the Institution of Electrical Engineers ( Volume: 78 , Issue: 471 , March 1936 )

    Page(s): 317 - 325

    Date of Publication: March 1936 

    DOI: 10.1049/jiee-1.1936.0051

    Publisher: IET

    ieeexplore.ieee.org/.../5317048

  • jcm:


    HSE leaflet  on Generators (No update ) but still relevant.

    OC 482/2: Electrical safety of independent low-voltage ac


    www.hse.gov.uk/.../oc482_2.htm

    Leaflet on Neutral inversion (No update) since 1936 (In your case original posters question  only for a read ) 

    Published in: Journal of the Institution of Electrical Engineers ( Volume: 78 , Issue: 471 , March 1936 )

    Page(s): 317 - 325

    Date of Publication: March 1936 

    DOI: 10.1049/jiee-1.1936.0051

    Publisher: IET

    ieeexplore.ieee.org/.../5317048


     


  • jcm:
    jcm:


    HSE leaflet  on Generators (No update ) but still relevant.

    OC 482/2: Electrical safety of independent low-voltage ac


    www.hse.gov.uk/.../oc482_2.htm


    Leaflet on Neutral inversion (No update) since 1936 (In your case original posters question  only for a read ) 

    Published in: Journal of the Institution of Electrical Engineers ( Volume: 78 , Issue: 471 , March 1936 )

    Page(s): 317 - 325

    Date of Publication: March 1936 

    DOI: 10.1049/jiee-1.1936.0051

    Publisher: IET

    ieeexplore.ieee.org/.../5317048


     




     


  • That 1936 paper on 'Neutral Inversion' is actually a quite well written 9 pages, and I can see why it is not superseded, so well spotted,   though I'd be surprised in the case of the OP's screw compressors the loads will be anything other than resistive or inductive, and I have yet to see a Peterson Coil (neutral earthing inductor) in any LV genset of the sort under discussion here, so coil resonance can probably be discounted.