emersion heater switch melting ?

Discussion in 'DIY' started by thecoops, Jun 21, 2011.

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  1. My emersion heater switch ( wires inside the switch ) keep melting ? it runs on its own 15 amp main the heater is wired up right the right fuze is in it. I just cant see how the wires melt after a couple of months I evan put a 30 amp cooker switch in still no joy any ideas whats happening and how I could fix it ?
  2. Are you talking about the supply cables in to the switch or the cables from the heater?
  3. Is the cable from the switch to the heater itself capable of 16 amp continuous, and are the connections at the heater end correctly and well made. The cable from the switch to the immersion heater is usually a specialist heat resistant flex.
  4. If it is the flex then there is a possibility that the CSA is too small for you load.

    Don't just uprate the fuse as this is dangerous remember the fuse is there to protect the cabling more than anything.

    If you have the wrong CSA then it will act as a heating element and with 15A you could possible be running a heating element in equivalent to 3.6KW which is hot :)
  5. fnarrr fnarrr

    "childs small anus?"
  6. Oh come on I was trying keep a serious face on :)
  7. the cables going in to the switch the ( feed ) if that makes sense. Its the flat 3 faze stuff
  8. Grumblegrunt

    Grumblegrunt LE Book Reviewer

    just the ones inside the switch or have you looked at the cable, how often and how long do you run it and is the heater itself set too high?

    no reason for the correct sized cable to melt as the elements, the switch wouldnt make any difference but its possible the thermostat is set wrong or the element is faulty. if you use it a lot then it could go hooky after a while.

    they arent so expensive, it might be worth changing the element or rewire it and watch it to see how quick it starts to cook.
  9. That sound like it. Whats CSA ?
  10. I only have the water on for an hour 2 at the most
  11. i would call a sparky if i was you.can see you going up in puff of smoke.
  12. Cross Sectional Area. i.e the size of the cable, if its twin and earth then it'll be 1.5mm , 2.5mm, 4mm etc etc.

    What size is the cable coming into the switch, just check its not a lighting circuit :)
  13. I think I mite have too I've been winging it too long now
  14. Grumblegrunt

    Grumblegrunt LE Book Reviewer

    2.5mm flex as thick as the stuff they put on extension cables to be safe. if it still cooks then change the element.

    how old is the house/fusebox? out of curiousity