Bathroom electrics

[frank999]

Hi,

I have 3x LV down-lighters in my bathroom, my ceiling is 2400mm high - so from what I can see this makes them neither zone 1 or 2, so they need not be special fittings - please correct me otherwise.

I am installing a Zone 1 LV fan right above the shower, I assume if the 240 supply and transformer are in the roof void above that is OK.

I am installing a loft, 100mm rockwool is being laid in chicken wire for Fire Regs, I am told I need fire hoods on the down-lighters - could I create these with plasterboard (75mm gap above, 100mm all around) ? Regarding the transformer could this just be screwed somewhere above the mineral wool - I assume some sort of access through the floor would be required if it ever went wrong.

Thanks

 

[PrenticeBoyofDerry]

Could you please define what you consider or understand LV =low voltage to be? I am assuming, maybe wrongly that you are really meaning ELV= extra low voltage@12V

Hi,

I have 3x LV down-lighters in my bathroom, my ceiling is 2400mm high - so from what I can see this makes them neither zone 1 or 2, so they need not be special fittings - please correct me otherwise.

Still need to take in to account of what is above, so fire, water moisture and sound. Should be considered.

I am installing a Zone 1 LV fan right above the shower, I assume if the 240 supply and transformer are in the roof void above that is OK.

I would say yes, providing the IP rating of the fan is suitable, the trany is offered ventilation and any electrical connection are made safely and are accessible and the manufacturers instruction say you can.

I am installing a loft, 100mm rockwool is being laid in chicken wire for Fire Regs, I am told I need fire hoods on the down-lighters - could I create these with plasterboard (75mm gap above, 100mm all around) ?

Likely you could but would be better to get the firerated cans and use loft braces for ventilation.

Regarding the transformer could this just be screwed somewhere above the mineral wool - I assume some sort of access through the floor would be required if it ever went wrong.

They need to be easily accessible for maintenance and inspection and testing plus they also require ventilation

 

[frank999]

Sorry, it is ELV, thanks.

My lights are in Zone 3:

Untitled

• frank999
• 15 Nov 2012
• 1

So do they need any rating ? (ie IP65 for zone 2, IPX7 for zone1).

The fan is SELV IPX7, I have an airing cupboard in the bathroom, so I'll stick the transformer in there, unless you see any issues with this.

Retro fitting hoods and braces is twice the cost of a new fire rated down lighter with a hood. Could replace the bulb with an LED bulb, no heat - so surely a simple plasterboard hood would suffice.

 

[PrenticeBoyofDerry]

Zone 3 no longer exists has not for over 4 years.
If the IP ratings are suitable for the zones and the MI states you can install them in a particular zone then you should be okay.
Zone 1 and 2 should have to be at least IPX4.
No issues with the trany providing it is outside Zone 2

 

[JohnW2]

I have an airing cupboard in the bathroom, so I'll stick the transformer in there, unless you see any issues with this.

How hot does it get in this airing cupboard, and is that temperature within the manufacturer's recommendations for ambient conditions? A particularly hot environment might well shorten the life of the tranny.

Kind Regards, John

 

[frank999]

There is a shelf above the airing cupboard, I will install the transformer there instead - I agree dont want to cook the components.

Sorry can you say what 'MI' stands for.

My diagram was scraped off some lighting co's site, looks like they need to update their info, I have 17th edition Explained & Illustrated book, and quite rightly shows no zone 3, according to the book my down lighters are not in any zone, so as the only thing in a zone is the fan - that is ELV - I assume I do not need to install RCD protection for that ?

I have all the gas, heating and water pipes by the combi boiler earth bonded - do I still need to add additional bonding in the bathroom ? I have a simple metal towel rail and toilet roll holder - would that require bonding ?

I have a pull cord light switch in the bathroom, could I replace this with a normal switch just outside the bathroom by the door ? (the clicking noise will be really loud from the loft).

 

[ban-all-sheds]

Sorry can you say what 'MI' stands for.

Manufacturer's/Maker's Instructions.

My diagram was scraped off some lighting co's site, looks like they need to update their info,

Yep.

Mind you - it was never right, there never were any zones associated with washbasins, they made that up.

so as the only thing in a zone is the fan - that is ELV - I assume I do not need to install RCD protection for that ?

It's not possible to put SELV wiring on an RCD.

I have all the gas, heating and water pipes by the combi boiler earth bonded - do I still need to add additional bonding in the bathroom ?

Well, firstly there is no need to have bonding on the boiler pipework, (it's not earth bonding, BTW), unless it's actually in the bathroom, and even if it were you'd probably only need to run a cable to the cpcs of circuits supplying appliances etc in the room, as you'll probably find that all the boiler pipework is soundly connected together at the manifold...

And secondly having it bonded does nothing to affect any requirements for supplementary bonding in the bathroom, unless it's very close and all the bathroom pipes are bonded. You'd still need to connect to the cpcs though.

Surely your 17th Edition Guide tells you all about main and supplementary bonding, and the circumstances under which the latter can be omitted from bathrooms?

I have a simple metal towel rail and toilet roll holder - would that require bonding ?

Only in the Wild and Wacky World that exists inside the head of a certain Mr. David Cockburn

//www.diynot.com/forums/viewtopic.php?t=228045&start=0

//www.diynot.com/search/forum-author.php?search=david911cockburn

I have a pull cord light switch in the bathroom, could I replace this with a normal switch just outside the bathroom by the door ?

Yes. Bear in mind the rules for concealed cables, RCD protection etc. And subject to considerations of external influences and Zones you could have a wall switch in the room if you wanted.

 

[JohnW2]

so as the only thing in a zone is the fan - that is ELV - I assume I do not need to install RCD protection for that ?

It's not possible to put SELV wiring on an RCD.

I agree with the rest of what you say, but I think you might possibly confuse the OP with this statement. I presume he was talking about the LV feed to the SELV 'transformer', and your answer may give him the impression that it is not permitted (or 'possible') to use an RCD-protected circuit for that purpose.

Kind Regards, John

 

[ban-all-sheds]

I presumed he wasn't, as he said all that was in the zones was the fan itself.

 

[JohnW2]

I presumed he wasn't, as he said all that was in the zones was the fan itself.

He did, and that was presumably the reason he went on to say that he assumed this emant that RCD protection was not required. However, I would have thought he was thinking about RCD protection for the (LV) circuit which fed it (any such RCD quite probably being distant, in the CU), not RCD protection for the SELV circuit istelf. However, as always, I may be wrong.

Kind Regards, John

 

[ban-all-sheds]

Well, in that case the fan transformer would need to be in the zones, wouldn't it?

 

[frank999]

As the 240v supply going to the tranformer is in the bathroom (a partly enclosed area above airing cupboard - adjacent to the bath but separated from the bath area/zone by tiled concrete wall board, it will also be above the 2.25 zone) - does that require RCD protection ?

With the Bonding, just read this article:
http://www.electriciansforums.co.uk...5-supplementary-bonding-connections-cpcs.html
And read my 17th Explained and Illust.
OK, as I have no 240v supplies in zone 1 or 2, do I still need to (do I use 4mm earth wire ? or can I used thinner) connect earth wire to all CPC's, exposed metal parts (towel rail and toilet roll holder - what about metal window and door handles). Whats is an 'extraneous conductive part' ?

I have bonding across all pipework on my combi - the bathroom is just above the kitchen (where the combi is) - do I need to bond the bath, taps and sink taps ?

Thanks