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Earthing Schematic Query

me1899
Hi all, hope you are well.


Just a quick question on the attached snippet from a drawing - basically for an energy centre and on their earthing schematic all earth bars are shown as follows:

2d8a9081c4e99b3842ad8d5034691cf8-huge-image.png

186e551d172cd9b4b75db7f34dac3af9-huge-image.png


The big text above is the drawing revision text saying the change was deliberate.


I would have thought the above is not right - the main conductor should be connected to the other side of the disconnecting link.


What they have done on site is install a different earth bar as follows:

3c6872262d573da80ef744d085327faf-huge-image.png


Disconnecting link is wrong way round?


I am not sure of the rationale behind this?


Any ideas?
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  • 0
    Thank you for the revised drawing -  so long as the link is fitted, electrically it does not matter - it's only purpose is to act as a ssort of switch that needs tools (but cannot be locked) to isolate the end terminal. In this case that can be done just as well, as you have to have the spanners anyway, by undoing the end bolt.  Swing links make a lot of sense when you have chunky earth cables or lightning conductor style strips that are rigid and cannot be sprung out of the way - its the sort of thing you see in big buildings with installations of a few hundred amps and up. If the wire is just 10mm2 or whatever, you'd not normally expect to see a link, as it is just another thing to shake loose, or for the installer to forget to tighten. They may have had quality control problems in that area, and decided it is safer to not use the link,
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  • 0
    Thank you for the revised drawing -  so long as the link is fitted, electrically it does not matter - it's only purpose is to act as a ssort of switch that needs tools (but cannot be locked) to isolate the end terminal. In this case that can be done just as well, as you have to have the spanners anyway, by undoing the end bolt.  Swing links make a lot of sense when you have chunky earth cables or lightning conductor style strips that are rigid and cannot be sprung out of the way - its the sort of thing you see in big buildings with installations of a few hundred amps and up. If the wire is just 10mm2 or whatever, you'd not normally expect to see a link, as it is just another thing to shake loose, or for the installer to forget to tighten. They may have had quality control problems in that area, and decided it is safer to not use the link,
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