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Old incomer connected to four 3 phase cutouts help

Simon M
Hi all,


I have a very old incomer entering the building that then feeds to 4 x 3ph cutouts. You can see two of the 3ph cutouts in the pic.
9f8642aebed8db60e40f7a2578ffd3a3-original-02.jpg


The incomer says on it  - BI Callender's - 4E 150 x 3. I assume this means 3 x 150 Amps? Please do correct me if I am wrong.


1. What is the maximum power I can draw from this system?


2. If each of the 4 Three phase cutouts were loaded with 100 Amp fuses and I was to pull close to that from each fuse. what would happen to the incomer as this would equate to 1200 Amps!


3. Is connecting 4 3ph cutouts to this old beast a reasonable thing to do? Or is it ridiculous?


Many thanks

Simon
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  • 0
    Hmm given the red yellow blue spots, if original, it should not be fused neutral (that era would be read white and blue or the red white and green that preceded it), though it may well contain asbestos flash pads, in which case the DNO will not want to open it, but either leave it sealed, or if they really have to replace it, they can do that unopened by cutting the supply cable further back.

    The grey box above may contain something like line taps or Henley blocks to split the tails, it looks too small for a bus.

    In any case it is all under company seals, and is not really your problem.

    It may be worth verifying Zs is low enough to blow a 150Amp fuse before the DNO get there, so if it is not, you can get them to do something about that at the same time.

    And that trunking may be mitred, but it looks like it is not earthed, is that the case ?

    Mike.

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  • 0
    Hmm given the red yellow blue spots, if original, it should not be fused neutral (that era would be read white and blue or the red white and green that preceded it), though it may well contain asbestos flash pads, in which case the DNO will not want to open it, but either leave it sealed, or if they really have to replace it, they can do that unopened by cutting the supply cable further back.

    The grey box above may contain something like line taps or Henley blocks to split the tails, it looks too small for a bus.

    In any case it is all under company seals, and is not really your problem.

    It may be worth verifying Zs is low enough to blow a 150Amp fuse before the DNO get there, so if it is not, you can get them to do something about that at the same time.

    And that trunking may be mitred, but it looks like it is not earthed, is that the case ?

    Mike.

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