Replacing Extractor Fan

Discussion in 'Electrics UK' started by diydot, 8 Nov 2021.

  1. diydot

    diydot

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    Hi

    I want to replace the extractor fan that I inherited in my bathroom, which has now broken. It had a timer on it. It came on when the light was switched on and then turned off a certain amount of time after the light was turned off.

    The old one currently has 3 wires attached to N, L and LS.

    The new fan needs to be connected to Neutral, Permanent Live and Switched Live. I'm assuming L = Permanent Live and LS = Switched Live. Would you agree?

    However, having read some similar posts on this site, I'm thinking that there should also be another earth wire. The other posts suggest that this should be folder over and kept away from the other 3 wires.

    I've added some photos. Appreciate your help on this.

    Thanks
    Rich

    20211107_121552.jpg 20211107_121630.jpg
     
    Last edited: 8 Nov 2021
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  3. sparkwright

    sparkwright

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    It would seem the earth core has been used for the switched live.
    Not ideal - should at least be sleeved both ends with brown sleeving.

    By rights the cable should consist of 3 cores AND an earth wire.

    If it's easy to change the cable, it would be a much better job.

    Admittedly the real earth wire wouldn't actually get connected to the fan, it would just get terminated in a separate connector block - but there you go.
     
  4. markyd1

    markyd1

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    Cable needs changing so that there is an earth to protect the cable and must be rcd protected so you need a 3core and earth
     
  5. EFLImpudence

    EFLImpudence

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    Not so.
    The regulation stating a CPC(earth wire) must be run to all points is merely for future need.

    Mmmm. Is that the case for a replacement item - in a loft?

    That might be the case if a socket RCD or possibly a FCU RCD were used but
    Consumer Unit RCDs do not use or need the CPC(earth wire)
     
    Last edited: 9 Nov 2021
  6. EFLImpudence

    EFLImpudence

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    I got muddled with the other thread with in-line fan in the loft but my points still stand.

    Appliances do not require RCD 'protection' - the circuit might if new.
     
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  7. markyd1

    markyd1

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    Surely once you change a fitting in a bathroom it then needs rcd protection as you were the last one to touch that circuit and are then responsible to make sure it meets the regs
     
  8. plugwash

    plugwash

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    Yes.

    There is a green/yellow wire in your picture but it is not being used as an earth wire. This raises a couple of issues.

    The first is that BS7671 requires an earth wire to be taken to each point and each accessory. A fan is not an accessory but if the flex feeding the fan is fixed wiring then the terminals of the fan are a point. Your picture appears to me like the flex is burried in the wall, in which case I would argue it is fixed wiring and therefore to be compliant there needs to be an earth core.

    The second is that a green/yellow core has been used for something other than earth. Doing this without marking it as such using sleeving is noncompliant and can become dangerous if the next person to work on the installation does not notice what has been done. Even if it is marked then it's questionable practice though depending on how exactly you read the relavent regulation it might be barely passable.

    Putting all this together I would assume that the fan was installed by someone who either didn't know or didn't care about good wiring practices. My next question at that point would be "what else has this guy done".
     
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  10. winston1

    winston1

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    But the so called regs are not statutory.
     
  11. EFLImpudence

    EFLImpudence

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    The appliance doe not need an RCD.

    The circuit has not been altered.

    Different when you fit a socket as that does need an RCD.
     
  12. diydot

    diydot

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    Thanks everyone for your help on this.

    To confirm, the flex is buried in the wall and the earth wire has been used for the Switched Live (LS).

    Based on the above, ideally I would replace the cable with 3 cores and an earth. However, since this is in the ceiling, it is difficult to do without damaging the ceiling. The earth wire running to all points is for future need, so not required at present. Therefore, I can continue to use the cable which is there. Best practice would be to change the sleeve so that the wire is brown at both ends.

    I do not need to install an rcd, as I am not fitting a socket or changing the circuit.

    I hope I've got that correct.

    Thanks.
     
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  13. joe384

    joe384

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    I think that all you can realistically do.

    All my extractor fans have the earth wire just sleeved and tucked in the housing so it seems most extractor fans do not have an earthing point anyway.

    It is annoying when things aren't wired correctly, my mums thermostat was wired with earth as one of the live connections and I've come across many light switches which are a total mess
     
  14. EFLImpudence

    EFLImpudence

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    It's not the end of the world.

    As Plugwash says, the regulations do allow a green and yellow wire which is insulated throughout its length (in flex unlike twin and earth) to be used for purposes other then earth if identified as such.

    So, to be accurate, if the g/y is used as a live conductor then it is not "the earth wire" or "earth" being used but merely the g/y wire.
    Similarly a black or blue wire used as switched live at light switches is NOT "the neutral" as many people say.
     
  15. diydot

    diydot

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    Great. Thanks.
     
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