Sparkys ... Measuring cables

Discussion in 'General Discussion' started by Dub and Dubber, Nov 7, 2022.

  1. Mark distances on the carpet, then stick the energised cable across your tongue.

    The distance you're thrown across the room will give you a rough idea of the current-carrying capacity.
     
  2. Dub and Dubber

    Dub and Dubber Supporter

    Why didn't I think of that?! Thanks m8 you're a trooper
     
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  3. Dub and Dubber

    Dub and Dubber Supporter

    Reminds me of the time our Physics teacher Mr Davey (haha) flew across the room mid safety sentence that day we were doing capacitors :thumbsup:
     
  4. Is it Twin and Earth? Flat cable with a smaller, bare Earth wire in the middle? Is the Earth wire a single, solid one or is it stranded like the live and neutral?
     
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  5. mikedjames

    mikedjames Supporter

    Dont worry, there will be a good reason you need new cable.. can the existing cable be inspected for damage ? When was it manufactured? the insulation will have lost plasticiser so cracking may be a thing..

    According to that website its about £3 a metre plus VAT for 10mm2 . Compared with paying a sparky for half an hour, the stupid price of a mains socket with a microprocessor and a relay or two called a charging point , new cable is peanuts.. scrap it.
     
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  6. Dub and Dubber

    Dub and Dubber Supporter

    That is definitely already on the options list :thumbsup:
    Have inherited a tethered "dumb" charger to get us going btw.
     
  7. Dub and Dubber

    Dub and Dubber Supporter

    Will have a look when I can ... but I think yes stranded earth in a flat-ish twin and earth cable
     
  8. You can discount 10mm2 T&E, it's much bigger than 6mm2. So it's either 6mm2 or 4mm2, you hardly ever see 4mm2 so I'd suggest taking a small offcut of it to a DIY store and compare it to their cable.

    I'm going for 6mm2
     
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  9. Dub and Dubber

    Dub and Dubber Supporter

    THAT is an excellent idea.
    I'm losing my touch :oops:
     
  10. 1mm, 1.5mm and 2.5mm T+E are all solid cores. 4mm usually, but not always, is stranded live and neutral with a solid earth.
    6mm is usually the smallest size with a stranded earth core.
    Hope that helps :thumbsup:
     
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  11. And 4mm isn't that uncommon, not since designers started moving away from ring mains and use more radial circuits for power.
     
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  12. Dub and Dubber

    Dub and Dubber Supporter

    It does ... but will be comparing "in store" all the same
     
  13. I'm washing my hair and cutting PTFE into tiny bits so it can't be used
     
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  14. Just remember once connected to keep a torch nearby when charging car for when 40 year old main fuse goes and domestic cables have smaller cpc or be careful not to hammer earth stake in too deep

    Sent from my SM-A127F using Tapatalk
     
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  15. Dub and Dubber

    Dub and Dubber Supporter

    Main fuse is young-ish.

    Earth cables all appear to be stranded and on the chunky side.

    Too deep?
     
  16. mikedjames

    mikedjames Supporter

    Theres also a good line in new 100 amp breakers fitted for car chargers going up in smoke at the distribution board end because they were not really designed to run flat out for hours.
    Just as well we need to use metal housings these days.


    Our local sailing club was recently quoted £1 a unit for stupidly expensive electricity ( they have found much cheaper now ) . At that price its cheaper to fill up my Bay Window for a 220 mile range than to charge an EV. The future maybe...
     
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  17. Pudelwagen

    Pudelwagen Supporter

    No, no, no! PTFE is so useful for electrics. Much better than pvc tape for wrapping live wires!
     
  18. Dub and Dubber

    Dub and Dubber Supporter

    We are indeed going to change the main board to a metal box when the 7kw unit gets installed.
    I've set our night rate hot water immersion to be on 20 minutes and off 20 minutes to mitigate that whole cable-heat-up issue.
    It's the right cable but the paranoia set in ... Would do the same with an EV charger ... and would make sure there's never a multiple load to challenge the main fuse capacity.
    "Learning" and quickly forgetting lots of stuff about chargers "shifting curves"/overly fast breakers/B type thingummybobbies blah blah ..... Still looking for a non-chaotic "grounded" local sparky to work some magic :rolleyes:
     
  19. matty

    matty Supporter

    a good charger will do that for you
     
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  20. None of that makes any sense. If your immersion heater cable is properly rated, it's not going to heat up. Ditto for every other cable. In a normal domestic environment, you'll get nowhere near the 60 or 100A rating of the main supply.

    Is your charger really going to run at 7kW for prolonged periods (that's two-and-a-bit three bar electric fires)? Your electricity bills are going to be eye-watering :eek:
     
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