Bathroom Luminaire Question

[Nottsneil84]

A friend want's a luminaire installing above his bath/shower as he obviously needs more light. I've not actually gone to look at the job as he lives in Leeds but I'm due to do the job this weekend and taking a look then.

Although the light will be outside the Zones likely (2.25m off FFL) I'm still wanting to consider it Zone 1 and use a 25v/12v downlighter and preferably IPX5 (withstand water jets). Is that overkill or just good practice?

But my main question is I'm guessing the lighting will be the loop-in-loop out method, can I just loop off the nearest light fitting with a 25v luminaire with its own transformer.

• Would I have any problems if the current down lighters in the bathroom are already on a shared transformer, in which case would I just need to find a down lighter with matching voltage (likely a 25/12v ac - 30/60 dc).
• Would I have issues connecting a lower voltage down lighter, say a 12v connected to a lighting circuit sharing a 25v transformer (or would it work fine as long as the supplying voltage is above the new light and the 12v transformer will just step it down again).
• If the circuit is not protected by a 30 mA RCD should I even bother touching it/safely isolate and move the circuit to the RCD protected side if possible as the Regs state it should be (guessing it will be protected as the building is a fairly new build but you never know).

Any answers, advice or tips would be greatly appreciated. Thanks.

 

[Richard Burns]

Even if it is out of zone it must be suitable for the environment so fitting a shower rated downlight would be sensible as it is over the shower.
If you are adding a light then you need to install in compliance with BS7671 so would need to have 30mA RCD protection, so long as you can get to a 230V supply then you can wire in an individual downlight, you just may have problems with switching it from the same switch; generally use the 230V switched supply from the existing lights, using suitable transformers where necessary.
Most ELV downlights are 12V ac not 25V.

 

[Nottsneil84]

That's what I thought and was going to supply it from the switch/line of the existing lights so it operates on same switch. Just I've never came across or considered if you can attach an ELV light to a circuit already containing a shared ELV at a possible voltage of 25v in zone 1 as the regs state it's acceptable subject to manufacturers instructions. Just wondered if that could cause me problems. If they were all mains voltage with individual transformer there'd be no problem.

Main thing is i need to see it first so I know what I'm working with!

 

[NickD]

I'm still wanting to consider it Zone 1 and use a 25v/12v downlighter and preferably IPX5 (withstand water jets). Is that overkill or just good practice?

Individual choice depending on your risk averseness. Obviously will need to be IP2X. Unless he plans to direct the shower at the light I would think IPX4 was sufficient.

Would I have any problems if the current down lighters in the bathroom are already on a shared transformer, in which case would I just need to find a down lighter with matching voltage (likely a 25/12v ac - 30/60 dc).

Need to consider whether total load placed on transformer is within its rating...maybe that's obvious

Would I have issues connecting a lower voltage down lighter, say a 12v connected to a lighting circuit sharing a 25v transformer (or would it work fine as long as the supplying voltage is above the new light and the 12v transformer will just step it down again).

You mean drive the input to the 12V from the 25V output? Is that what you're asking? Only if the spec of the 12V says it will take a supply voltage down to 25V and cares not at all about the waveform of its supply. This seems extremely unlikely. Most stuff you buy will expect 230Vac input.

If the circuit is not protected by a 30 mA RCD should I even bother touching it/safely isolate and move the circuit to the RCD protected side if possible as the Regs state it should be

Not sure what you need to do to test and certify it if you do that. Arguably you have changed the protection scheme (but not the OCPD) for the circuit and need to retest and recertify the circuit?

One way or another what you are adding will need to be 30mA RCD protected. It is also, I would have thought, Building Control notifiable as an addition in a special location. Though I'll admit to being not that up to speed with the recent relaxations of the building regs in this area.

 

[Nottsneil84]

Yes I was thinking if the other existing down lighters are on a 25v transformer then it might not be a sufficient voltage to supply the supposed new 12v down lighter. Also if its is mains voltage, is it acceptable to keep the 230-12v transformer next to the light in the shower or is it advisable to locate it outside of zone 1 and then link it to the light fitting.

As to me you wouldn't want a 230v source within anywhere near zone 1 even if in the ceiling it is classes as outside zones and has a suitable light fitting preventing water ingress into the ceiling/light fitting.

 

[NickD]

Source of SELV has to be outside the zones.

 

[Nottsneil84]

Cheers. Thought as much.

 

[Richard Burns]

What you need to do is fit a shower rated downlight in the location.
If you want to use a 12V downlight then you will need to be able to fit a 12V lighting transformer to the downlight, the transformer will need a 230Vac supply.
The 230Vac supply will be available above the ceiling somewhere as any other ELV downlights will be wired in the same way, whether from a single main transformer or from multiple transformers. Whichever way they will need a 230V supply.
Tap into that 230V supply to feed your individual transformer for the new light.
If you have taken the supply from the other lights in the bathroom then the supply will already be switched.
Having a 230V to 12V transformer in the ceiling above the bathroom is normal practice as it would take removing the downlight or the ceilign inorder to get to it so they is minimal risk of exposure.
Inside the ceiling void, or in the loft, is outside of the bathroom as the bathroom is defined by the walls and ceilings.
30mA RCD protection is now required for all low voltage (230V) circuits in a bathroom.

The work could be covered by a minor works electrical installation certificate and in England would be notifiable to building control as it is the alteration of a circuit within the zones of a bathroom.

 

[telectrix]

What you need to do is fit a shower rated downlight in the location.
If you want to use a 12V downlight then you will need to be able to fit a 12V lighting transformer to the downlight, the transformer will need a 230Vac supply.
The 230Vac supply will be available above the ceiling somewhere as any other ELV downlights will be wired in the same way, whether from a single main transformer or from multiple transformers. Whichever way they will need a 230V supply.
Tap into that 230V supply to feed your individual transformer for the new light.
If you have taken the supply from the other lights in the bathroom then the supply will already be switched.
Having a 230V to 12V transformer in the ceiling above the bathroom is normal practice as it would take removing the downlight or the ceilign inorder to get to it so they is minimal risk of exposure.
Inside the ceiling void, or in the loft, is outside of the bathroom as the bathroom is defined by the walls and ceilings.
30mA RCD protection is now required for all low voltage (230V) circuits in a bathroom.

The work could be covered by a minor works electrical installation certificate and in England would be notifiable to building control as it is the alteration of a circuit within the zones of a bathroom.

says it all. concise and clear post.

 

[GLENNSPARK]

check that all main bonding & any necessary crossbonding is present as well wont you as its a 2 if it isn`t...as would the absence of RCD should crossbonding not be present within the zones...