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12v Fan

Former Community Member
Former Community Member
I am fitting a fan for a friend which is going to be in zone 1, opposite side of bath/shower, is there a fan which is suitable for this? It is about 6ft up from the bath, it’s a small room. I’ve looked at the low volt ones but the transformer is to big, which I have no where to hide it. Do they do them with smaller transformers? Possibly 230v one?


The fan won’t be needing a time delay as to limit any damage they just wanted it to come on and straight off with the light.


clint
  • 0
    is there any scope for the fan to go in the loft and some ducting ? Normally the transformer goes in the loft or in the airing cupboard or in an adjacent room - putting it by the fan rather defeats the point - bit like the builders who run their rattiest looking 230V cables through the mud to plonk a 110V transformer beside the cement mixer.

    If not, you can fit a mains fan in zone 1, but only if the makers say it is suitable, which restricts the range of models rather. And it has to be supplied via an RCD, so do not just  spur off the lights willy nilly if they are a supplied by 6A hot wire fuse...
  • 0
    Years ago, building regs did not require forced mechanical ventilation if a source of natural ventilation was present.

    To translate, basically you did not need to fit a fan if a window could be opened in the same room.

    However, with the move towards this green nonsense and the widespread installation of 'warm roofs', the building regs changed, and now you have to fit mechanical ventilation, even if there is the facility of opening a window instead.

    Moreover, there would appear to be a requirement for any fan to be a timed in order to clear any residual humidity after the light has been switched off. Most fans are wired to come on with either the lights, or via some kind of (usually unreliable and short-lived) humidistat device, so you will have to provide a 'permenant live' for the fan timer in order to comply with building regs.

    In order to site the transformer, is there not any way of situating it on the other side of the wall from the bathroom?

    That is what I am doing on my present job - 3A fused spur, then transformer, then 3 pole fan switch and 12VAC cable going through wall to fan inside bathroom from outside.
  • 0
    I fit a lot of extractor fans. We try to, mostly, fit ELV models in bathrooms, but for a like for like replacement, we fit a suitable mains voltage model.

    The transformer is usually fitted in a 2 gang box above the bathroom door.

    There are many mains fans suitable for Zone 1. Yours sounds quite a long way from spraying water, so look into these, even the cheapest is Ok, I've got one in my kitchen.:
    https://www.greenwood.co.uk/product/147/select-100
  • 0
    As said, the transformer is not huge and is easily accomodated outside the bathroom at least one socket/switchplate distance below the ceiling to allow some airflow to circulate. That way you have mains in (Low Voltage) and 12V out (Extra Low Voltage). Note it is Seperated Extra Low Voltage (SELV) therefore no earth.

    In England and Wales the addition of an extracor fan to a bathroom is notifiable under Part P of the Building Regulations
  • Former Community Member
    0 Former Community Member
    Thank you to all for the replies.


    Unfortunately this bathroom is part of an extension, which is a flat roof. So going above is out the question.


    The electrics are on an RCD board, as I wouldn’t of touched the fan if it wasn’t on one.


    I have came across this “ https://www.click4electrics.co.uk/domestic-fans-c-118_805/monsoon-zone-1-silence-timed-extractor-fan-mons100t-p-8235?gclid=EAIaIQobChMItdWQ1vKY5QIVVuDtCh2dVgtkEAQYAiABEgIFMfD_BwE “

    Obviously the timed I’ll have to link out, I just find it alarming having 230v basically in a shower area/bath.


    tell me what you think



    Also, the room does have a window , but unfortunately they don’t want to rely on this and don’t want to have damp/condensation creep up. 


    Clint
  • Former Community Member
    0 Former Community Member

    whjohnson:

    Years ago, building regs did not require forced mechanical ventilation if a source of natural ventilation was present.

    To translate, basically you did not need to fit a fan if a window could be opened in the same room.

    However, with the move towards this green nonsense and the widespread installation of 'warm roofs', the building regs changed, and now you have to fit mechanical ventilation, even if there is the facility of opening a window instead.

    Moreover, there would appear to be a requirement for any fan to be a timed in order to clear any residual humidity after the light has been switched off. Most fans are wired to come on with either the lights, or via some kind of (usually unreliable and short-lived) humidistat device, so you will have to provide a 'permenant live' for the fan timer in order to comply with building regs.

    In order to site the transformer, is there not any way of situating it on the other side of the wall from the bathroom?

    That is what I am doing on my present job - 3A fused spur, then transformer, then 3 pole fan switch and 12VAC cable going through wall to fan inside bathroom from outside.



    unfortunately the bathroom is tiny, the wall they originally wanted it on was going to be right next to shower head, I can’t go further to door as the window goes across there. Then your at other wall. 

    The wall opposite the shower then towards the door is back to back with neighbours , so it can’t be put there, unless the neighbour agrees ?.. Leaving the only wall being is inside the bath area. Reason I cannot go for a huge transformer fan . If I can have one with a little one, there’s a chance I can find some cavity to try slot it in




     

  • 0
    I may have the wrong mental picture, but surely the wall with the door is not opening  to the neighbours or to outside ? Assuming not then how about the  transformer over the door outside the bathroom ?
  • 0
    Generally you can have three metres of 12 volt cable between the Tx and the fan, which should give you a bit of room to manoeuvre.


    Andy Betteridge
  • Former Community Member
    0 Former Community Member

    mapj1:

    I may have the wrong mental picture, but surely the wall with the door is not opening  to the neighbours or to outside ? Assuming not then how about the  transformer over the door outside the bathroom ?




    your correct, but the problem being is there isn’t an easy way to get to the door with a L&N, the switch is only SL & PL. there isn’t a neutral, so going from the light to the other side of door involves cutting slots across ceiling, due to the joists running horizontal 




     

  • Former Community Member
    0 Former Community Member
    Can you use a lights transformer? I found a 12v fan at a decent price but it doesn’t come with transformer, if I can get away with a light transformer, I could put this in the ceiling at the size of them.

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