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Thread: Phase bridged in council box

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    Phase bridged in council box

    Hello all,

    I encountered something very strange today and was wondering what a few of you might have to say...

    I noticed that in the council supply box (on supply side of the breaker), one of the phases has been bridged. So, coming from the council, Red phase and white phase are connected, the blue phase has however been disconnected, and a bridge piece installed from the White phase to last pole on the supply breaker where the Blue phase initially was.

    Something obviously went wrong and so this was done, which we will investigate and rectify. But I am very curious to know whether what has been done is compliant??? Is there a regulation around this? because essentially there is only a 2 phase supply in the house at the moment. I only picked this up while testing. Not at all clever as this could cause problems should someone ever connect a 3 phase load!!

    Thanks in advance!

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    Site Caretaker Dave A's Avatar
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    Quote Originally Posted by Clive287 View Post
    Something obviously went wrong and so this was done
    Or perhaps not.

    We came across an instance of a 2 phase supply about a year ago, and upon querying this with Brian Bilton (via ECA SA Durban) we established it was indeed by design. The back story is there was a point in time when (in this case the Durban municipality) had a tariff scheme that differentiated between "power" consumption vs "light" consumption. As a result, it became quite popular for larger houses in some areas to have two phase supplies in the arrangement you describe - one for heavy draw circuits such as stoves and geysers, and the other for light circuits.

    When the tariff arrangement disappeared, over time the meters were replaced with normal 3 phase meters with only two phases connected.

    Some tell-tale signs would be just 2 phases connected at the meter, and a two phase main distribution board.
    The trouble with opportunity is it normally comes dressed up as work.

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    Hi Dave,

    Many thanks for your response. I have heard of the older 2 phase supplies, but thanks for the clarity around it. However for this installation it is definitely not the case as the main DB and Sub DB have been wired for 3 phase. The meter has also been wired for 3 phase.

    I was able to get the council to test their supply cable and they found that the blue phase has been damaged, so all they did was disconnect both sides, and install a bridge from white to blue on the supply breaker. Obviously checking with the client if they had any 3 phase loads first. My task is to try get them to repair their cable. This is all in a fairly new upscale complex.

    My question is more around whether how it currently is, if that would be compliant? Surely not, as White and Blue phase in all the DB's are essentially the same phase. So to issue a COC, both Main and Sub DB would have to be re-arranged for 2 phase supply... something I'm not really familiar with.

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    Site Caretaker Dave A's Avatar
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    And you shouldn't be reconfiguring for a two phase installation if it's only a temporary situation. Just imagine what will happen when they return the blue phase if the white and blue phases have been treated as one and the same elsewhere in the installation

    The EIR's are clear you may not issue a COC while there is a fault, so best to put pressure on the supplier to correct it.
    The trouble with opportunity is it normally comes dressed up as work.

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    Absolutely not (reconfiguring to 2 phase), the house has new owners and according to them about a year ago was issued with a COC as it currently is. I have told him the blue phase has to be repaired before we can supply a new COC (we are currently doing renovations). The owner is now taking this up with the previous owner who will as you know take it up with the electrician who issued a COC at the time.

    So I am simply getting my ducks in a row, obviously it would be idiotic to configure the home for 2 phase. First time I come by something like this, so now I know.

    Thanks

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    Quote Originally Posted by Clive287 View Post
    Absolutely not (reconfiguring to 2 phase), the house has new owners and according to them about a year ago was issued with a COC as it currently is
    It'll be interesting to see what they put down as the phase-to-phase voltage readings in the test report.
    The trouble with opportunity is it normally comes dressed up as work.

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    Judging by what I've found in the installation so far most likely 3 phase and 380 between all phases. The standard of workmanship almost everywhere I go is shocking. Yesterday the council were able to repair their damaged cable so all 3 phases are available again

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