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Isolator Switch for Bathroom Extractor Fan

Discussion in 'Electrics UK' started by Gaurdian65, 4 May 2010.

  1. Gaurdian65

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    Hi All
    Newbie on DIYnot.
    Im replacing an extractor fan in the Bathroom with a same brand.
    The new fans instructions says that a 3 pole isolator switch should be fitted however, the current fan which worked absolutely fine over several years did not have an isolator switch.
    Is an isolator switch a must?
     
  2. Taylortwocities

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    Has your bathroom got a window? It is a 100% requirement if there is no window.
     
  3. Gaurdian65

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    Yes it does have a window
     
  4. Taylortwocities

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    Then there is no regulation that says you MUST have a fan isolator.
    It is good practice to fit one though.
     
  5. holmslaw

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  6. Gaurdian65

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    Thankyou top everyone who responded.
    Due to siting of fan and wiring etc can the Isolator switch be placed inside the bathroom near the fan, and if its an issue due to the steam and humidity etc is there a waterproof Isolator switch.
    Sorry for sounding a bit dumb but Im trying to establish just how big a job it may become if the Isolator switch has to be sited outside the bathroom.
     
  7. GaryMo

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    Where would the isolator be if it was by the fan in relation to the floor and bath/shower? Height from floor and distance from bath/shower

    Do the Manufacturers Instructions also state that the fan must be protected by a 1A or 3A fuse?
     
  8. Gaurdian65

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    Thankyou.
    The Isolator would be a foot away from the fan, and it would be 7 feet from the floor and 4 feet from showerhead.
    In the wiring instructions there is a mention of 1 Phase supply 220-240V 50Hz, and the Live feed shows a 1 Amp fuse
     
  9. GaryMo

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    You'll need a fused spur with a 1A fuse to comply with the MI.

    You mention 4ft from the shower head? That's around 1220mm.
    Measurments are taken from the basin and your fan isolator must be a minimum of 600mm away (2ft).
     
  10. Gaurdian65

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    Gary Thankyou

    I can confirm that the switch will be at least 4 feet from any water source.
    the fused spur with 1A which you mentioned, does that act as the Isolator switch or is it in addition to the Isolator switch,and lastly does it have to be waterproof :oops:
     
  11. GaryMo

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    It probably does as you mention a 3 pole isolator but just checking - does this fan have an over-run timer? ie it runs for 10 mins or so after the light has been turned off?

    If it does, how is it currently wired? One single 3 core and earth cable originating from the light fitting?

    If the isolator is more than 600mm from the edge of the shower base then it doesn't need any special protection.
     
  12. Gaurdian65

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    Thankyou Garymo
    1.It is a new fan which has not been fitted yet.
    2.The previous fan was wired in without earth or an Isolator switch.
    3.The new fan is double insulated and must NOT be earthed (per instructions)
    4.The new fan has a timer set at 15mins after it is switched off.
    5.yes it will be more than 600mm away from any wet source bar any steam etc.
     
  13. GaryMo

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    You'll still use a 3 core and earth cable to supply the fan but terminate the earch (cpc) in a small connector block.

    Have you got an accessible loft over the bath/shower room? If so, are you against surface mounted backboxes at high level outside your bath/shower room door, on the landing? If you want a neater option then you'll need to consider chasing into the wall.
     
  14. Gaurdian65

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    Thankyou Garymo
    No accessible loft as its an extension to the House.
    Im happy to have it surface mounted in the Bathroom at least 3ft+ away from any wet source.
    To recap:
    1A fused spur will act as Isolating switch and can be sited inside the bathroom as long as its 600mm min away from shower/water sources etc.
    A waterproof switch would be ideal but not an absolute must as long as it is safe distance as you mentioned min 600mm.
    If this is correct then I'll give the go ahead. :rolleyes:
     
  15. GaryMo

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    It's not going to be so simple but it's very acheivable. You're going to have to create more damage than you probably wished for though.

    You've got a permanant line, a switched line and a neutral.
    A FCU is double pole, meaning it can only isolate two poles, normally permanant line and neutral. Your switched line will still be live.

    Have a look at the wiring diagram which came with the fan and you'll see that the 1A fuse is situated before the swiched line comes into play so that it's protecting both the permanant and switched lines.
     

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