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Panel Wiring Used External to an Enclosure. 400 Volt.

Zoomup
Hello, I hope everyone is fit and well.


I have been doing some work in an intake building that is really an old locked wooden shed at the edge of a holiday chalet park. The original installation dates back to the early 60s. Modern distribution boards exist that may be 30 years old.


The metering is via three current transformers. The single insulated wiring, about 1.5mm2 that runs from the current transformers goes to the metering equipment in a steel enclosure, and is open to touch at shoulder height.


Also, there are three spring loaded test switches and three neon indicators in the metering enclosure that test the presence of three phases.


 Three supply phase cables (6.0mm2)  run in insulated and sheathed cables to three 16 Amp. "slide lok" fuses carriers on the surface outside the metering enclosure. Open to touch, but insulated and sheathed. From the three fuses the wires seem to be single insulated instrument wire, open to touch, that run to the metering equipment enclosure test lamps.


Was this ever normal? Three single insulated 400 Volt wires running at shoulder height, not enclosed, surface run, open to touch.


Z.


  • 0
    No OMS but it quickly improves the description of how it really is!


    You have been quiet recently, not ill I hope?

    Regards

    David
  • 0
    Colin Jenkins:

    Hello Zoomup

    Be careful with the Slydloks. A colleague of mine had a big fright when pulling out a live rewireable Slydlok fuse on no-load. It flashed to earth and gave his hand and arm a temporary suntan. Make sure they're dead before touching them. Regards, Colin.


    Thanks Colin, I ain't touching the sealed slydloks as they are metering company owned. I value my life. I have already been told off for removing a sealed cover to test when we had a power supply problem. U.K.P.N. have now resealed the equipment.


    Z.


  • 0
    OMS:
    Zoomup:
    whjohnson:

    Slide-loks were usually employed to protect the CT control wiring if I remember correctly. Some were rewirable and some were cartridge.

    In any case, it is nothing to do with the site/installation owner.

    Probably not worth flagging up to be honest.


    The slide locks are in series with the 400 Volt three phase single insulated wires that supply the three test neon lamps. The current transformer output wires are not externally visibly fused.


    Z.




    You wouldn't see fuses in the CT's as if a fuse were to operate and leave a CT open circuit the voltage would be seriously lethal


    Just as an observation, aren't all fuses "in series" - they wouldn't be much use at all in parallel would they ?


    Regards


    OMS




    Yes, I already knew that about current transformers. Ref. fuses, I was clarifying things for the layman OMS. 


  • Former Community Member
    0 Former Community Member
    davezawadi (David Stone):

    No OMS but it quickly improves the description of how it really is!


    You have been quiet recently, not ill I hope?

    Regards

    David


    No, all good thanks - staying well away from the Covidiots and cracking on as usual


    Stacks of work at the moment given that we are in the biggest recession since God was a little boy in short trousers


    I'm not sure I'm actually seeing a problem on this metering unit, tbh - a photo would be useful


    Regards


    OMS


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