An earth spike and standby systems

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  • Isetech
    Platinum Member

    • Mar 2022
    • 2274

    #1

    An earth spike and standby systems

    Just when you thought nothing else could create confusion, well add an earth spike to the mix. Imagine that neutral bar earthing again


    Take note of the earth wire to the electrode (spike as we call it) it must be at least equivalent to the phase conductor. If you have a 16 mm phase wire in an 8 KVA or bigger, then a 16 mm earth wire is required.

    If a 5 KVA is installed and you decide to use 4 mm phase conductors, then a 6 mm earth wire to the electrode is still required.


    The question, when is an earth electrode required? Do you just knock an electrode into the ground and connect it to the main earth, the standby unit and the solar panel rails?



    7.12.3.1 Neutral bar earthing


    7.12.3.1.1 Protection in accordance with the requirements of 6.7 shall be
    provided for the electrical installation in such a manner as to ensure correct
    operation of the protection devices, irrespective of the source of supply or
    combination of sources of supply. Operation of the protection devices shall
    not rely upon the connection to the earthed point of the main supply when the
    generator is operated as a switched alternative to the main supply.


    Where there is no existing earth electrode installed in the electrical installation,
    a suitable earth electrode may be installed in accordance with SANS 10199.
    When installed, the electrode shall be bonded to the consumer's earth terminal
    and to the earthing point on the alternate supply by a conductor of at least half
    the cross-section of that of the phase conductor, but not less than 6 mm2
    copper, or equivalent. This also applies to a single-phase supply


    (see also 5.2.3.1).


    NOTE 1 In a TN system earthing of electricity supply, an earth electrode is normally
    not required in an electrical installation.


    NOTE 2 Protection of photovoltaics can be by means of or surge protective device
    (SPD)

    Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.
  • GCE
    Platinum Member

    • Jun 2017
    • 1473

    #2
    Why they changed the "shall" to " may " makes no sense and would not be surprised to find out it was a typo

    In the beginning of 7.12.3.1.1 it clearly states that you shall ensure correct operation and not rely upon the connection to earth of the main supply

    7.12.3.1.1 Protection in accordance with the requirements of 6.7 shall be
    provided for the electrical installation in such a manner as to ensure correct
    operation of the protection devices, irrespective of the source of supply or
    combination of sources of supply. Operation of the protection devices shall
    not rely upon the connection to the earthed point of the main supply
    when the
    generator is operated as a switched alternative to the main supply.


    Where there is no existing earth electrode installed in the electrical installation,
    a suitable earth electrode may be installed in accordance with SANS 10199.
    When installed, the electrode shall be bonded to the consumer's earth terminal
    and to the earthing point on the alternate supply by a conductor of at least half
    the cross-section of that of the phase conductor, but not less than 6 mm2
    copper, or equivalent. This also applies to a single-phase supply

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