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Bathroom Fan. Isolator ... and Fused Unit ?

Discussion in 'Electrics UK' started by frank999, 27 Jan 2020.

  1. frank999

    frank999

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    Hi,
    Does a 240v Fan above a shower (above 2.5mt height) require a 'Fused Unit' - in addition to a Fan Isolator Switch. The feed is from a lighting circuit, which itself is RCD protected.

    Thanks.
     
    Last edited: 27 Jan 2020
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  3. terryplumb

    terryplumb

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    No it doesn't.
     
  4. winston1

    winston1

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    As Terryplumb says 'no'. Nor does it require a fan isolator switch.
     
  5. flameport

    flameport

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    Depends on whether the manufacturer's instructions require one, and if you are going to follow those manufacturer's instructions.

    Technically no isolator required, but one should be fitted so the fan can be isolated from the rest of the lighting circuit. At some point that fan will get full of water / trip RCDs / make a lot of noise when the bearings fail. With an isolator, it's just a matter of turning off a switch. Without one, you will have no lighting until the fan is disconnected from the circuit.
     
  6. delmel

    delmel

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    If its a new build it should have an isolator on the bathroom fan, most older installations will not have an isolator switch outside the bathroom.
     
  7. bernardgreen

    bernardgreen

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    Flameport's advice is correct.

    Winston's "advice" is wrong
     
  8. aptsys

    aptsys

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    Not really. There's no requirement for a fan isolator, and the regs only say you should take account of the MI, not that you are specifically required to follow them.
    Obviously it makes sense to install one for convenience.
     
  9. bernardgreen

    bernardgreen

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    Convenience or safety, Being in a house at night without lights is not just inconvenient...... it can be hazardous.

    OK the manufacturers and the people who wrote the " regulations " may consider loss of lights is acceptable. Is it acceptable in real life ?
     
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  11. aptsys

    aptsys

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    Why are we losing lights?
     
  12. bernardgreen

    bernardgreen

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    Because the defective / damp fan unit is causing the RCD or the MCB to trip thus removing power from the lighting circuit to which the fan is connected. Until the fam is disconnected from the lighting circuit the RCD or MCB cannot be reset.
     
  13. aptsys

    aptsys

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    How is that different from any other fault on a lighting circuit?
     
  14. bernardgreen

    bernardgreen

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    How many lights in a house have a permanently connected Live supply to the lamp ? Almost all lights have an accessible switch that disconnects the Live from what could be a damaged lamp holder, a fan should have a similar accessible switch ( isolator )
     
  15. frank999

    frank999

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    Thanks for the replies, but I'm asking if the fan also requires a Fuse Unit to go in next to the Isolator.

    "and the regs only say you should take account of the MI" - what does MI stand for please.

    One of the fans is at 2200mm ceiling height above a fixed shower head, zone 1, all house circuits are RCD protected at the CU, would this satisfy Regs ... or does it need its own RCD next to the Isolator, I guess alternative would be to fit a Low Voltage fan, which maybe preferble.

    Thanks
     
  16. bernardgreen

    bernardgreen

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    Manufacturer's Instructions or Manufacturer's Information

    The over current protection will be provided by the MCB ( Miniature Circuit Breaker ) in the Consumer Unit hence additional fusing to protect against a current overload due the fan becoming faulty could be seen as un-necessary. Some manufacturers would disagree with this.
     
    Last edited: 28 Jan 2020
  17. winston1

    winston1

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    MI are often wrong. A 3a fuse will not provide discrimination against a 6a MCB generally.
     

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