Bathroom loo vent ok with 6A RCBO

Discussion in 'Electricians' Talk' started by Dnsmith, Sep 16, 2021.

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  1. Dnsmith

    Dnsmith New Member

    I know about the debate about the benefits or not of fitting either a 3a or 5a fuse as per manufacturers instructions, if we could park that.
    Does anyone no of a 100mm unit that does not specify this and csn be fitted on a 6a rcbo without contravening instuctions.
     
  2. Coloumb

    Coloumb Screwfix Select

    Regardless of the debate, the regs specify that motors require "readily accessible" isolation, so you would still have to comply with this whilst staying within the remit of the zonal system required by the location being a bathroom. This mean you can either fit a 3 way isolator if it's a timed fan or a 2 way if not. If you fit a 2 way it might as well be a fcu.
     
  3. Dnsmith

    Dnsmith New Member

    Have been thinking of a grid switch arrangement for bathroom light + fused unit (neutral loop)
    Then run perm and swiched live& N through 3 pole isolator to fan.
    Hopefully save inadvertant operation of a fcu if at standard switch height.
     
  4. The Happy Builder

    The Happy Builder Screwfix Select


    Which reg?
     
  5. Big K

    Big K New Member

    If tou have a fan isolator in place replace it with a Click one that incoparets fuse & TP fan switch all on a single plate
     
  6. Coloumb

    Coloumb Screwfix Select

    Jeez. Your the one making a living out of being spark. You tell me. Surely this would be bread and butter knowledge to you?
     
  7. Jimbo

    Jimbo Screwfix Select

    If you’re that bothered about it and assuming it’s an inline fan, fit a 3 module Din rail enclosure by the fan and grab a three pole 1A MCB off eBay.
     
  8. The Happy Builder

    The Happy Builder Screwfix Select

    Which reg says you need anything more than the MCB at the origin of the circuit?
     
  9. Coloumb

    Coloumb Screwfix Select

    For motors it's the one you can't be bothered to look up. Do you actually have a copy of the regs?
     
  10. Dnsmith

    Dnsmith New Member

    My original question was quite specific.
    Dooes anyone know loovents that do not specify that they need either 3a or 5a fusing.
    Yes there are 3 pole isolators with in line fuse (in perminent live) - does not comply with manufacturer instructions.
    Yes there are other solutions, but equally probably then break accessability requirements.
     
  11. seneca

    seneca Screwfix Select

    I think you'll find that the Manrose ones don't specify a 3 amp fuse, as long as they're on a 6 amp breaker.
     
  12. The Happy Builder

    The Happy Builder Screwfix Select

    Try harder and quote the reg number.

    I will quote 537.3.2.2, the note at the top of page 184 of BS 7671:2018 specifically states that a circuit breaker can be used for switching off for mechanical maintenance, as well as a multipole switch and several other devices.

    Over to you @Coloumb
     
  13. The Happy Builder

    The Happy Builder Screwfix Select

    Use a Greenwood AXS100T fan, you can remove the pull cord if you don’t want it and it switches on from the light or a separate switch.
     
  14. Coloumb

    Coloumb Screwfix Select

    What is this?

    You're the one out there charging your customers as a skilled "professional" yet you don't even know the regs well enough to understand that fixed motors need local isolation? You can denied it all you want yet I am telling you there is a reg and you need to go and look it up; I would think it's the least you can for your clients, don't you?
     
    Dnsmith likes this.
  15. The Happy Builder

    The Happy Builder Screwfix Select

    Sorry @Coloumb you just aren’t trying hard enough.

    Turn to page 544 of BS7671:2018 and in the index look for “Motors- mechanical maintenance, switching off for” and you will see that it refers you to the note after 537.3.2.1.

    That note on page 183 tells us that if the electrically powered equipment is within the scope of BS EN 60204 then that standard applies.

    A domestic extractor fan doesn’t fall within the scope of BS EN 60204 so “537.3.2 Devices for switching off for mechanical maintenance applies” and that clearly states the circuit breaker can be used in the note to 537.3.2.2 so a RCBO can be used as it serves the purpose of a MCB.

    Feel free to tell me the regulation I should be looking at.
     
    Last edited: Sep 17, 2021
  16. The Happy Builder

    The Happy Builder Screwfix Select

    I’m the only one who has actually answered the question :rolleyes:

    If you are actually wiring a switch outside the door stick with convention and install a three pole fan switch (not many of them are actually isolators, they are switches) then run 3 core and earth or two 2 cores if you don’t have any to the switch and install a two gang switch, one to turn the light on and another for the fan.

    Actually you really need 3 core to wire the fan itself, so you should have some three core to run to the switches as well, simply loop across the back of the switches to share the permanent live between them.
     
    Last edited: Sep 17, 2021
  17. Coloumb

    Coloumb Screwfix Select

    That means if it ISN'T a fan, ie some sort of industrial machinery, then you must use the standard that applies to the machinery, ie BS EN 60204, not BS7671. I would presume BS EN 60204 might have completely different requirements to BS7671. Who knows?

    In any case, as you have stated, the fan certainly does not come under BS EN 60204 so we can safely assume that it DOES come under 7671. And, this being the case, there is a reg that specifies, clearly and unambiguously, the for the need for some sort of device to be fitted for switching off the fan, or rather motor, which is readily accessible.

    That is the reg that you can't find. So I would say unfortunately it's still you not trying hard enough. But there we are.
     
  18. Coloumb

    Coloumb Screwfix Select

    If you mean switch as in light switch or pull cord, which I think you do, that won't comply with the regs.
     
  19. The Happy Builder

    The Happy Builder Screwfix Select

    @Coloumb Please, please me and tell me which reg you are referring to.
     
    Last edited: Sep 17, 2021
  20. Coloumb

    Coloumb Screwfix Select

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