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Maintenance free approach to jointing different CSA conductors

psychicwarrior

Good day

An effective and regulation justifiable maintenance free joint of differing CSA e.g. 10mm to 4mm: is it realistic and if so what might satisfy please and specifically the splice approach (crimp, screw terminal , etc) ?

(A similar  question some time back produced the suggestion of a compound filled joint perhaps - but that was for matching CSA )

Or is it a case (as it feels) that a joint like this really ought to be accessible for maintenance because of its factors ?

Thank you.

Parents
  • 0

    I was taught never to use pre-tinned for mains, as it makes a resistive joint

    Weren't most mains cables tinned during manufacture in the old imperial days? (originally to prevent sulphur in the vulcanised rubber insulation affecting the copper, but the practice seemed to continue into the days of PVC - certainly imperial T&E), Presumabbly if tinning were a problem it would be so for screw joints as well as soldered.

       - Andy.

Reply
  • 0

    I was taught never to use pre-tinned for mains, as it makes a resistive joint

    Weren't most mains cables tinned during manufacture in the old imperial days? (originally to prevent sulphur in the vulcanised rubber insulation affecting the copper, but the practice seemed to continue into the days of PVC - certainly imperial T&E), Presumabbly if tinning were a problem it would be so for screw joints as well as soldered.

       - Andy.

Children
  • 0 in reply to AJJewsbury
    AJJewsbury said:
    Presumabbly if tinning were a problem it would be so for screw joints as well as soldered.

    There's a difference between someone with a soldering iron applying a thick layer of lead and tin via solder ('pre-tinning') vs a layer of higher-concentration tin (much lower concentration lead as it used to be) during manufacture of tinned copper conductor.

    Tinned ends (with solder, particularly lead-tin solder, but also quite possibly silver-tin) are a problem for screw terminals ... Regulation 526.9.2 ... whereas the use of tinned copper wire is not.

  • 0 in reply to gkenyon

    Graham, just to introduce a sense of perspective - how much resistance does an average in-service but aged light switch have across it's contacts? Or even a male to female contact resistance of a plug and socket outlet whose appliance hasn't been unplugged in a decades?

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