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Thread: Genny regs?

  1. #1
    Gold Member Sparks's Avatar
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    Genny regs?

    Hi Guys, it has been hectic here in the Windy City. I need to know if the regs have changed while I have been working my ass off. According to a Master Electrician here the changeover switch need only break the Live line not the neutral. I have never heard of that but have been so busy I have no idea. Even if it has changed I would still not do it but I just need to know. Thanks.

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    Bronze Member ACEsterhuizen's Avatar
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    Hi there this is all I can find. The regulation consistently refers to "annex s" 1 through to 4 shows exactly how it should be wired?

    7.12.2.5 Where an alternative supply is provided to an installation or part of
    an installation as a switched alternative to the main supply, the change-over
    switching device shall disconnect the main supply before the alternative
    supply is switched in. The change-over switching device shall be interlocked
    in such a way that the main supply and the alternative supply cannot be
    connected to the installation or part of the installation at the same time.
    Amdt 6
    7.12.2.6 Except where otherwise permitted in this part of SANS 10142,
    where a socket-outlet is installed in a circuit on standby power, such circuit
    shall be protected by an earth leakage protection device with a rated earth
    leakage tripping current (rated residual current) I Δn not exceeding 30 mA.
    Amdt 6
    7.12.2.7 A 230 V generator with a V-O-V earth connection (centre tap on
    winding which is earthed), shall not be connected to a fixed electrical
    installation. Amdt 6

    NOTE Such a generator may be used as a free-standing unit to provide power to
    specific appliances.

    7.12.3.1.2 In an installation that is supplied from a combination of
    transformers and alternative supplies located near to each other, including an
    alternative supply (supplies), the neutral points of each of these items shall
    be connected to a single earthed neutral bar (see annex S)
    . This earthed
    neutral bar shall be the only point at which the neutral of the installation is
    earthed. Any earth leakage device shall be positioned in such a way as to
    avoid incorrect operation due to the existence of any parallel neutral/earth
    path. Amdt 6
    7.12.3.1.3 Where alternative supplies are installed remotely from the
    installation, or from one another, and where it is not possible to make use of a
    single neutral bar which is earthed,
    the neutral of each unit shall be earthed
    at the unit and these points shall be bonded to the consumer's earth terminal
    (see 6.12.4).

    The supply from each unit which supplies the installation or part
    of the installation, shall be switched by means of a switch that breaks all live
    conductors operating substantially together (see annex S), to disconnect the
    earthed neutral point from the installation neutral when the alternative supply
    is not connected (see also 6.1.6). Amdt 1; amdt 6


    (6.1.6 The neutral conductor shall not be connected direct to earth or to
    the earth continuity conductor on the load side of the point of control.)

    7.12.3.1.4 Where only part of an installation is switched to the alternative
    supply in the same distribution board, the neutral bar shall be split (see
    figures S.2 and S.3 in annex S).

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    Diamond Member AndyD's Avatar
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    I'd ask the ME for evidence the neutral can be unswitched and please let me know what he's based this advice on cause I'm genuinely interested. I'd disagree with him on this point and suggest the neutral should always by switched.
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    Gold Member Sparks's Avatar
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    My sentiments exactly Andy. The sod claims Escom endorsement, they do not endorse anyone. He also claims SESSA registration which is also false. I have advised his client to hold back payment.

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    Diamond Member AndyD's Avatar
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    Ahh, I thought you had personally heard it first hand from a genuine ME when I saw the opening post...which was kinda worrying. I even combed through the latest amendments in case I'd overlooked something or misinterpreted something but even common sense and general basic electrical theory would never make single pole changeover an option. Advice like this is going to get someone injured or killed.
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    Gold Member Sparks's Avatar
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    Exactly, it is a 3pole change-over but he is not utilising the other 2 poles

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    FML!

    The things people can come up is amazing.
    No Sparks, no changes yet published in regards to alternative supply and switching device requirements for such. It still clearly states that both the live an neutral conductor shall be broken with such device. Amendment 9 is expected soon and if all goes well (which we know with DoL normally it does not) we will have our new updated SANS1014 part 1 next year with medical locations removed and alternative supplies added (PV solar)


    On 3 phase thou...now that is a lil bit of the grey area where people like to make their own rules, since on the supply side you only break L1,L2 and L3 and not the neutral and then on single phase you are required to break both Live and neutral, it seems that this makes people think this also applies to change-overs.
    Understanding the reason behind why an alternative supply, such as an generator needs to have its own earth and not rely on the supplier earth is also the reason why the neutral is isolated from the supplier neutral

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    The neutral definetly needs to be isolated from the eskom supply when running on backup generator power. As you could end up energising the eskom feed line and hurting someone doing maintanance work etc

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    Hmmm, can the main swith feeding for example a shopping centre be used to feed an auto change over switch (connected on auto change over switch for mains) and then a supply from generator to ATS and then ats (load) to the main db of the shopping centre? The ats installed is also not breaking neutral

  10. #10
    Bronze Member ACEsterhuizen's Avatar
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    Regs (Annex) on 3 phase change over switch for, in this case a gennie because: (which is used as standby power) and how it is recommended to be wired according to the annex: no grey areas..:-) Neutral not broken. (TN System) IMHO

    Click image for larger version. 

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    Last edited by ACEsterhuizen; 14-Oct-15 at 08:28 PM.

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