Neutral split

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  • Hotspot
    Full Member
    • Jun 2016
    • 28

    #1

    [Question] Neutral split

    Good day all,

    I am currently busy with alterations at a small factory that is in the proses of being sold and would also require a CoC. While working a came across this neutral(50mm) in the SUB DB which has its stands split and connected independently to the neutral bar due to the fact that the neutral bar cannot accommodate the size.
    I would like to know if this is acceptable and where it states in SANS?
    I have located the previous electrician that did this job and he says its acceptable because the size of the neutral is not reduced.

    Any input?

    Thanx
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  • AndyD
    Diamond Member

    • Jan 2010
    • 4946

    #2
    Yeah, I've also come across some pretty creative solutions to terminating oversize wiring in the past as well. Clearly if the wire won't fit in the hole then it will be contrary to the manufacturers specifications for that product to terminate it.
    I can't tell the dimensions of the neutral bar from the photo but if it's 7x9mm then the max current is usually 60 or 70 Amps, 8x12mm is normally limited to 100A (from memory) so if the wiring is 50mm˛ then there's also a good chance the neutral bar is also undersized for the OCPD in the DB.
    My take on it is it's not compliant as it is but if you can find a 50mm pin lug or maybe a palm lug that will fit in the hole without butchering it first and if the neutral bar is current rated to same or greater than the main breaker then you might be in with a shout.
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    • GCE
      Platinum Member

      • Jun 2017
      • 1473

      #3
      Hi

      SANS 10142 Ed 2 pg 137 - 6.3.7.2 c - Joints and terminations shall not allow the strands of a stranded conductor to spread

      That reg should solve any argument

      Comment

      • Hotspot
        Full Member
        • Jun 2016
        • 28

        #4
        Hi,

        Thanks a lot guys, this will surely help.
        Will inform the owner and the person that has done this work to correct it at his own expense .

        Thanx

        Comment

        • BEVIN
          Full Member
          • Aug 2018
          • 35

          #5
          Good day all
          If I may ask a question concerning the split neutral
          When a manual change over for a single phase generator is installed.the db is split and the essential circuits are supplied with it's own neutral bar .when gen is on then neutral comes to it fine.when it changes back to mains. It's neutral now from mains.am I not understanding but the gens neutral will have a bridge with the mains neutral.if so .is this correct? Please educate me
          Thank you

          Comment

          • Derlyn
            Platinum Member

            • Mar 2019
            • 1748

            #6
            Originally posted by BEVIN
            Good day all
            If I may ask a question concerning the split neutral
            When a manual change over for a single phase generator is installed.the db is split and the essential circuits are supplied with it's own neutral bar .when gen is on then neutral comes to it fine.when it changes back to mains. It's neutral now from mains.am I not understanding but the gens neutral will have a bridge with the mains neutral.if so .is this correct? Please educate me
            Thank you
            No.

            There's no bridge between Eskom and generator neutrals.
            Thats what the changeover switch is for.
            The installation gets either an Eskom neutral OR neutral from generator.
            The changeover switch sees to it that both cannot be simultaneously connected.
            Either one OR the other.

            Comment

            • Isetech
              Platinum Member

              • Mar 2022
              • 2274

              #7
              My advise to you, find someone who understands the power produced by a generator. You need to understand the voltage output, if and when you need to bond the neutral and earth and if you require an earth spike and all that stuff.
              Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

              Comment

              • Derlyn
                Platinum Member

                • Mar 2019
                • 1748

                #8
                @BEVIN

                Refer to diagram P.2 on page 325 of SANS 10142-1:2020 Edition 3.

                Pay attention to the change over switch.
                The switch is shown in the "main supply on" position. You will notice that the neutral from the generator is isolated.

                There's your answer.

                In the older reg book, the diagram can be found on page 357.

                Hope this helps, my brother.

                Comment

                • Derlyn
                  Platinum Member

                  • Mar 2019
                  • 1748

                  #9
                  @Bevin.

                  Also take note of what it says just above the change over switch.

                  I quote "change - over switch to break all live conductors including neutral"

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