1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Immersion Heater Timer Burning Out

Discussion in 'Electrics UK' started by wolfie2010, 20 Oct 2010.

  1. wolfie2010

    wolfie2010

    Joined:
    20 Oct 2010
    Messages:
    5
    Thanks Received:
    0
    Location:
    Wolverhampton
    Country:
    United Kingdom
    Hi All,

    I've got a problem with my immersion heater timer burning out.

    A few months the wires leading up to and inside the timer literally burnt/melted. A friend of mine who knows more about this sort of stuff went into the loft to push through some of the grey cable and he put in a new timer. Everything worked fine up until today when I noticed a burning smell again, this time the white cable coming from the immersion heater to the timer has burnt the live out and neutral out wires.

    I've turned the breaker fuse for the immersion heater off in the CBU.

    Question is could this be a problem with the element in the immersion? Also is it possible to get a timer with a higher resistance?


    Many Thanks
     
  2. Sponsored Links
  3. vsynth

    vsynth

    Joined:
    7 Dec 2007
    Messages:
    196
    Thanks Received:
    3
    Country:
    United Kingdom
    Either the cable is too small to carry the required current or you have a fault and the device protecting the circuit is overrated or faulty.

    Can you tell us the rating of the fuse or circuit breaker supplying the circuit?

    What are the contacts rated at on the timer and were the connections tight?
     
  4. wolfie2010

    wolfie2010

    Joined:
    20 Oct 2010
    Messages:
    5
    Thanks Received:
    0
    Location:
    Wolverhampton
    Country:
    United Kingdom
    Hi the cable installed from immersion to timer is a 2.5mm and the fuse is 16a.
     
  5. TicklyT

    TicklyT

    Joined:
    30 Jul 2006
    Messages:
    3,481
    Thanks Received:
    337
    Location:
    Hampshire
    Country:
    United Kingdom
    The previous overheating may have led to some softening and oxidisation of the cable cores.

    Softening (annealing) of the copper allows it to deform, so connections that were fully tightened when installed work loose and overheat.

    Oxidisation leads to high resistance joints that tend to overheat, causing further softening and oxidisation

    etc.

    etc.

    Until the connection fails.

    It's high resistances that cause the problems. The higher the resistance, the more power dissipated as heat.
     
  6. wolfie2010

    wolfie2010

    Joined:
    20 Oct 2010
    Messages:
    5
    Thanks Received:
    0
    Location:
    Wolverhampton
    Country:
    United Kingdom
    Hello

    I purchased one of these timers from a local electrical supplier

    http://tinyurl.com/3al5fap

    Just a bit baffled with the wiring as there seems to be no where to connect the earth cable from the immersion and from the mains to the timer?

    Any help much appreciated!
     
  7. Steve

    Steve

    Joined:
    15 Apr 2005
    Messages:
    16,486
    Thanks Received:
    244
    Location:
    Yorkshire
    Country:
    United Kingdom
    What terminals are there? What are they labelled? If theres only two terminals its just live and switched live. You terminate the neutral and earths seperately.
     
  8. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
  9. Sponsored Links
Loading...

Share This Page