Bathroom lighting circuit load

[Mark80]

Hi,
I am renovating a bathroom, and would appreciate some advice regarding load on the lighting circuit.
The room currently has a loop-in batten lampholder.
I would like to install the following : LV downlights @ 6x50W, extractor fan @ 15w, shaver socket/mirror light @ 35w (15 bulb, 20 shaver).
This seems to add up to 350w, giving 1.5 amps. Is it acceptable to replace the existing ceiling rose/lampholder with a junction box and use this to supply all of the above?
Many thanks,
MarkP

 

[ZenStalinist]

Hi,
I am renovating a bathroom, and would appreciate some advice regarding load on the lighting circuit.
The room currently has a loop-in batten lampholder.
I would like to install the following : LV downlights @ 6x50W, extractor fan @ 15w, shaver socket/mirror light @ 35w (15 bulb, 20 shaver).

If the lighting circuit is exclusive to the bathroom, you have no problems where loading is concerned... Otherwise I need to know the other loads upon the circuits.

You should also note that there are zoning rules that apply to LV downlights. If you want lights above showers etc., you should use SELV lighting.
That said, I would like to clarify your use of the acronym. When you say LV do you mean regular 230v lighting (which is what LV generally refers to in lighting terms...)
Or do you mean those little 12 or 24 volt lights (those are actually SELV lights)??
As for the junction boxes, they ought to be accessible, and they must be out of zones...

 

[ban-all-sheds]

That said, I would like to clarify your use of the acronym. When you say LV do you mean regular 230v lighting (which is what LV generally refers to in lighting terms...)

That's not what people "generally" mean when they talk about low voltage lighting. Or low voltage anything.

Or do you mean those little 12 or 24 volt lights (those are actually SELV lights)??

C'mon Zs, you know full well that he does not mean that - how many people know that 230V is, properly, Low Voltage?

As for the junction boxes, they ought to be accessible, and they must be out of zones...

Above the ceiling is outside the zones...

 

[Mark80]

Thanks for the replies guys,
I can clarify a couple of the points :

By LV, I meant low voltage, ie lower voltage than the supply to my house. Sorry for the confusion, but I understood this to be generally referring to 12v lighting.

The existing bathroom batten lampholder is on the upstairs lighting circuit of a 3 bed semi.

The circuit is wired loop-in.

I propose to replace the lampholder with a junction box in the loft space, directly above its existing location.

From the new JB I was planning to feed the following :

- six 12v 50w halogen downlights, each with its own local transformer (in the loft space), fed by one cable from the jb, wiring the transformers in parallel, daisy chain style. The lights themselves are all in zone 3.

- one 15W extractor, using a 3 core + E to an isolator, then to the fan

- one shaving light/socket, fed directly from the jb.

Although the load is only 1.5 amps, I guess I really want to know what you think about the load AND the number of cables in the JB, which just seemed to be rather a lot to me, ie

Two 1.5mm2 for the lighting circuit
One 1.5mm2 for the pull switch
One 1.5mm2 for the new downlights
One 3C+E for the fan supply
One 1.5mm2 for the shaving socket/light

Is it ok to put these all in one jb, as I think it will be rather crowded? I could use a 30 amp box, or is there a specific type I should use? Or an alternative wiring arrangement?

Thanks again,
Mark80

 

[dingbat]

By LV, I meant low voltage, ie lower voltage than the supply to my house. Sorry for the confusion, but I understood this to be generally referring to 12v lighting.

That should be ELV - Extra Low Voltage. As others have said Low Voltage is what your whole house runs on.

As for your junction box, you're quite right - it will be a nightmare to wire up. Why not use one 20A 4-way (get a big, brown, bakelite one, not one of those nancy white flimsy ones) in place of your existing ceiling rose, adding in a feed to a second JB from which you can wire in your new stuff? That way your existing lighting circuit can be easily identifed and if you have problems with your new kit you can isolate the lot for fault finding without disturbing whatever lights are downstream of the bathroom.

 

[Mark80]

Thanks for that reply Dingbat.

I'd wondered if there was something I could do to avoid spaghetti junction in the JB, but didn't know the 'proper' way to do it. Your suggestion makes good sense to me, I'll give that a go.

Cheers,
Mark80

 

[ban-all-sheds]

By LV, I meant low voltage, ie lower voltage than the supply to my house. Sorry for the confusion, but I understood this to be generally referring to 12v lighting.

That should be ELV - Extra Low Voltage. As others have said Low Voltage is what your whole house runs on..

But it's a very common term to use, and the mistake is perpetrated by all the products on sale labelled "Low Voltage Downlighters". Mark80 is quite right - in general usage, the term "low voltage" does mean 12V, and he doesn't need to be too apologetic.

And I'd love to know how many sparkies, when asked by their customers to install some "low voltage downlighters" put in 230V ones, and then insist on being paid on the basis of "well that's what you asked for".

 

[dingbat]

The 'proper way' is to design your wiring so that junction boxes are not necessary, but that's fine when you're starting from scratch. Even then I usually wire in wall lights via junction boxes as there is rarely room at the light to satisfactorily wire a loop in system. So long as your JB's are accessible - the loft is generally accepted as fine - and screwed to a joist or noggin then you should be fine.

 

[dingbat]

...I'd love to know how many sparkies, when asked by their customers to install some "low voltage downlighters" put in 230V ones, and then insist on being paid on the basis of "well that's what you asked for".

Oh that's quite brilliant! I'm going to start doing that - that'll learn 'em!! Trouble is few people will pay the price to do the job properly, LV or ELV. By the time you've added in the price of fire caps, factored in the hassle and time to move half their furniture or de-insulate their loft, dust sheet the entire room against plaster debris then clear up afterwards, all you get is a "How $£*@@$ much??!!" I'm seriously considering not bothering to quote for the damned things!

 

[securespark]

I've given up on them. When people ask I get "How much?", too.

They buy a 3 downlighter "Ring" kit from a shed with a 60VA tx and 3 20W lamps and think they're a instant spark.........

I also get asked to wire in floodlights people have bought for <10......yes you've guessed it "How much? The light only cost a tenner!!!!!!"

But if you wire properly off ring with sw spur etc.. it will cost.

Joe Public, eh? Who wants 'em??