downlighting and timed extractor fan in bathroom

[helix]

Hi all

I'm getting an electrician in to install downlighting and an extractor fan in my bathroom. The extractor fan will be of the timer variety.

I have had a number of quotes, and seemingly varying advice as to what regulations need to be followed. I would therefore like to understand myself what is required for this job.

Specifically my questions are:

1. Are low voltage lights / fan required if in zone 1 or zone 2 or is 240v ok?
2. Should I have two RCDs, one for the lights and switched feed to fan, and one for the continuous feed to fan (for timer)?
3. Can the RCDs be fitted in a cupboard within the bathroom, with a louvre door?
4. How would a fan isolator switch be wired with the two RCDs?
5. Could the fan isolator switch be located in the cupboard with the RCDs or does it need to be outside in the hall?
6. Can an in-line fan be fitted to a wall so that it would vent outside rather than into a loft?

Many thanks
Alex

 

[rebuke]

1. Not 100% sure on this off hand, so don't want to give you misleading info...
2. Not really any point - just have a single RCD protecting the lighting circuit, so both the fan and the lights are protected.
3. If it's outside of zone 2 it would be fine, if not then as the louvre door isn't solid, I believe the area would still count as in zone so wouldn't be ok. It might be easier though for your spark to simply change the MCB for the entire circuit to an RCBO.
4. Not applicable - you don't need two RCDs (and in fact you couldn't without the use of a contactor, as the fan will only have one neutral, so the permanent and switched live must be supplied from the same RCD).
5. Just needs to be somewhere accessible for maintenance, that's the reason it's there, so in the cupboard (assuming it's not in a zone) is fine.
6. Not an in-line fan no, but you can get wall mounting fans that can, you put some ducting through the wall to an appropriate grill on the outside.

 

[bernardgreen]

6. Can an in-line fan be fitted to a wall so that it would vent outside rather than into a loft?

Venting warm humid steamy air into a cold loft will result in condensation and then soggy wet insulation on your ceilings. Vent to the outside.

 

[LiamPope]

How high are your ceilings? Are you sure you have lighting in zones 1 and 2?

You can have a decent loft mounted fan that is ducted all the way out to eaves or gable wall. Eg the stuff here.

I've been advised the wall mounted radial fans are generally useless, so I'll be using one of the kits in the above link.

Liam

 

[helix]

Thanks for the replies.

Is this the type of RCD required:

http://www.alertelectrical.com/Wiri...CD-Sockets/RCD-Spur-Connection-Unit-S1275.asp

And I was thinking of this type of fan:

http://www.screwfix.com/prods/59811/Heating-Cooling/Extractor-Fans/Manrose-In-Line-21W-Bathroom-Fan

And this type of switch:

http://www.screwfix.com/prods/26547.../Marbo-Range/Marbo-6A-3-Pole-Fan-Isolation-Sw

There will be lighting directly over the shower and the bath. The ceiling above the bath is sloping so light there will be approx 1.5 metres above bath.

The light above shower will be approx 0.5 metres above shower head level.

There is already a vent in the wall, so don't really want to vent via the loft.

 

[rebuke]

I would let you electrician sort out the RCD - the one you link to is OK, and that would be one way of doing it (fitting this outside the bathroom to cover all the circuits), but it might be easier just to change the protection at the consumer unit.

That fan looks like it would work, although I'm not sure why they describe it as an in-line one, as that normally implies the fan unit being in the middle of the run of ducting (so you'd e.g. mount it in the loft, with a grill in the ceiling, and one to outside). You'll need to check what size the hole in the wall is already, to determine whether it would fit though...

Any 3-pole switch will be fine, so the one you've shown is OK.

 

[electronicsuk]

I think you will be disappointed with that extractor, I fitted an extremely similar model in a small wetroom at my parent's house (short story, flat roof, not many options) and it struggles to cope with that.

 

[helix]

thanks all.

So fitting the RCD as a separate unit near the consumer unit, would mean the whole lighting circuit is on the RCD?

Something like this would sit inline between the lights and the consumer unit?

http://www.screwfix.com/prods/68302...its/Volex-MCBs-Incomers/Volex-80A-30mA-DP-RCD

I was a bit suspect of the fan, being so cheap. Which fan would be recommended for an external wall?