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power shower isolator

Discussion in 'Electrics UK' started by mrcrow, 4 Sep 2015.

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  1. mrcrow

    mrcrow

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    my son is having his power shower isolator replaced again in just over a year as it has burnt the contact out again

    he was told to shut it off each time the shower was used and put it on to take a new power shower, even though there is a on of on the power shower casing and the temperature control when set at cool wont draw power??

    earlier he was told by another electrician who installed it years ago to leave it on and use the on off on the power shower casing

    we cant understand why it should be switched on and off every time since it is an isolation switch and the on off indicator is to assure the user it is off before doing work on the power shower

    we dont feel the latter component may have been of a high standard and ask as well if you chaps could suggest a good named component..like MK if they still do that unit

    he has an mcb type consumer unit

    cheers
    geof
     
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  3. Iggifer

    Iggifer

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    I quite like MK stuff generally, their shower pull cord isn't the best in their range, but it does the job.

    I generally advise against using the isolator to turn the shower on and off each time, invariably, the ones I've had to change because they've failed, they've been used as a switch to turn the shower on and off.

    I don't see anything wrong with just turning it off at the shower, it may use a minuscule amount of electricity in standby mode (particularly if there's a neon) but I wouldn't worry too much.
     
  4. sparkwright

    sparkwright

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    I have to say the MK shower pull cord is proving to be unreliable, sometimes you need to pull it several times for it to work.

    The circular Crabtree ones are the only ones that seem to be any good now - though you will find them a bit different to arrange the wires...
     
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  5. mrcrow

    mrcrow

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    thanks both..i have passed that on
    the crabtree i take it is a double pole switch...what is the difference in arranging the wires
    at present there are two cables from the loft
    one to the switch and one from the switch to the power shower

    cheers again
    geof
     
  6. JohnD

    JohnD

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    when you say "power shower" do you mean "electric shower?"
     
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  7. EFLImpudence

    EFLImpudence

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    Yes, it's double pole.

    The difference in wiring is that the terminals and actual switch is in the base which screws to the ceiling.
    The cover is just that.

    http://www.free-instruction-manuals.com/pdf/p4470433.pdf

    It is a lot easier than terminating wires in a loose switch which you then have to manipulate to get it in place to then screw to the base.
     
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  8. bernardgreen

    bernardgreen

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    An ON - OFF switch is designed to switch the load current many many times. An isolator is designed primarily to isolate a supply rather than act oas on ON - OFF switch. The type and operation of contacts will be different, ON - OFF switches often have a wiping action as the contacts colse to wipe the contacts clean. Isolators seldom have a wiping action. An isolator will ( should ) be designed to ensure isolation happens when required ands will switch full load current OFF a few time before contact wear occurs.
     
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  9. EFLImpudence

    EFLImpudence

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    Not sure about wiping action on domestic accessories.

    According to websites these switches are BS60669-1 which according to Table 53.4 are NOT suitable for isolation but emergency and functional switching.
     
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  11. ban-all-sheds

    ban-all-sheds

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    I've got an MK pull-switch for my shower. It's been used several thousand times, (and yes, I really do mean that), probably approaching 10,000, and it's still going strong.
     
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  12. kevindgas

    kevindgas

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    just a thought, what output is the shower? is the switch a square 40A one? wouldn't be the first i've come across with a 10.5 Kw shower on a 40A pull switch and yes they are usually toasted!!
     
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  13. mrcrow

    mrcrow

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    yes..sorry i realise power shower could be the one with a pump

    cheers
    geof
     
  14. mrcrow

    mrcrow

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    all the above answer posts..thanks
    what now seems to be something i will check with my son
    what does he have fitted...a switch or an isolator...point taken
    and
    the power ratings on the shower and the newly fitted...by an electrician...item whatever it is

    things get clearer each time i use this site and its big thanks to all who answered

    cheers
    geof
     
  15. ericmark

    ericmark

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    It would seem odd for a 40A switch to burn out with the 5A or so drawn by a power shower? These showers do not heat the water they only have a small motor and pump to increase pressure. Maybe some back EMF from motor or wrong names have been used and it's not a standard power shower?
     
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  16. ban-all-sheds

    ban-all-sheds

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  17. ericmark

    ericmark

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    There are so many I suppose you are referring to this [​IMG] as a typical power shower?

    For one I fitted I used a standard FCU as isolator with no problems from a 6A MCB until the boiler was changed and using a power shower became illegal as a result.
     
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