Advice fitting downlighters in Kitchen

I'm being coerced by my wife into fitting downlighters in our kitchen and have a number of questions:

  1. We live in a 7 year old 3 storey house (loft has been converted into a 5th bedroom). Bedrooms exist above the kitchen. Do the building regulations require fire integrity between floors? If so, should I be using flameguard downlighters or hoods?

  1. Big brother (the Labour government) has recently decided that we are not intelligent enough to tinker with home electrics. Is replacing existing light fittings with downlighters covered by this new legislation i.e. do I need to employ an electrician to do the job or can I do it myself?

  2. Am I likely to have insulation between the ground and 1st floor in a
7 year old house. I will check this when I get the chance but wondered if this was compulsary under building regs.

  1. Any recommendations on the types of downlighers to user (low voltage or mains voltage)? If insulation is present (question 3 above) I would probably go with mains voltage as they are less likely to overheat and don't need transformers that are also likely to overheat, however, on the down side, the bulbs will probably need replacing every 5 minutes and they won't produce as much light as a LV fitting. LV would be my preference, but although the bulbs will last longer, the transformers will probably need replacing from time to time!

I would appreciate your advice.

Paul.

Reply to
Milleniumaire
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Yes, especially in a 3-storey house, and yes.

In a kitchen or bathroom anything other than direct like-for-like replacement is notifiable work. Fitting new downlights probably counts as notifiable.

You can:

  1. Employ an electrician registered with one of the medieval guilds ^W^W Part P organisations

  1. DIY and submit a building regs application to the council

  2. Ignore Part P and do the work yourself anyway

Probably not provided the structure meets fire and noise transmission requirements

Low voltage

Transformers shouldn't need replacing often, and should be installed so they are accessible. In practice, if you use mains wiring to each lamp point and have individual transofmers that pop through the hole in the ceiling that covers most eventualities.

If you don't want to go buggring about with your wiring and ceiling you could try one of the lighitng sets where the halogens are suspended on wire stretched across the ceiling with a surface mounted transformer. Provided this is a CE approved set wired to an existing mains point, you can DIY it in a kitchen AIUI.

Owain

Reply to
Owain

On 9 Apr 2006 04:11:36 -0700 someone who may be "Milleniumaire" wrote this:-

Standard R80 or R64 fittings, fitted with compact fluorescent bulbs like

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will last a long time and not make your electricity meter spin round like a catherine wheel.

Reply to
David Hansen

Oh dear. That really is the most appalling type of lighting in a kitchen (indeed pretty much anywhere). I would strongly suggest a rethink (look back over kitchen lighting threads here in the past).

For your questions, Owain already gave same answers I would have.

Reply to
Andrew Gabriel

Interested in looking at those lighting sets you mentioned, on the wires stretched across the ceiling. Any idea where I can get them from... Shed's don't seem to stock them round here.

Ian

Reply to
Ian Cornish

Here's an illustrated how-to. NB: American site; safety standards and working practices will be different.

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and wire systems
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(click on Spot Lights on blue bar on left - 12V Halogen - Wire Systems)

Complete wire kits

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(Track and Wire in the Product Categories list on left)

Dare I mention IKEA - models SANSA, NORRSKEN, ISBRYTARE might be of interest.

Owain

Reply to
Owain

I spoke to my local building inspector who advised me that in domestic dwellings the ceiling between floors must be able to resist fire for upto 30 minutes. This meant that fitting downlighters would probably prevent this so they would need to include fire hoods (separate or built-in).

This week I had three electricians round to give me advice and a quote for fitting the downlighters. Two suggested that I would need 18 x 50w downlighters whereas one suggested 11 x 50w would be sufficient. The one suggesting 11 lights quoted building regulations, stating they would have to be fire-proofed i.e. use the safeguard type with a built in fire hood. The others said fire hoods were not necessary! One suggested we might have a problem with the load on the circuit as we were increasing it by 540W, so if all downstairs lights were on at the same time, the rcd may trip. The other two said the additional load on the circuit would definately not be a problem.

I'm rather alarmed at the conflicting views of the electricians and am even more confused about what to do than I was before! I have decided to hire an electrician to wire the lights up but I will probably do the donkey work myself (drill holes, raise floorboards etc.).

I have read that the electrician will need to be appropriately qualified to part p of the new building regulations and I will need to supply the building control body with an Electrical Installation Certificate signed by the electrician. You must be joking!

If this really is the case then none of the three electricians mentioned this to me!!!!

Paul.

Reply to
Milleniumaire

I thought that was only >= 3-storey buildings, but we have BCO's here who can correct me. OTOH, the wiring regs do state that the electrical installation should not result in holes being left in the building through which fire can spread, so they should be fireproofed for that reason, even if you don't need the 30 minutes protection by regulation.

Did you not stop at that point and think to yourself "this is a really REALLY stupid lighting design if it needs somewhere in the region of half to one killowatt to light a room"? Please go back to the drawing board and design a better lighting system. An important hint you already now have is that halogen downlighters are an appalling way to try and light a room. Read back over this topic in the archives of this newsgroup on Google for more details.

That appears to be the view of most electricians, the public, and many BCO's.

Reply to
Andrew Gabriel

The 18 x 50w downlighters are actually for two adjacent rooms with an archway between them i.e. the kitchen and the breakfast area, however it does seem like a lot of wattage when you put it that way, even when split 6 in one room and 12 in the other.

I've just calculated the total wattage on my existing downstais lighting circuit and it works out at 1978 watts. A = W/V suggests that this will give a 8.24 amp draw which is in excess of the 6A rcd! I guess this would only be a problem if the lights were all switched on at the same time and although we have never experienced a problem this does concern me.

Should I be concerned about this potential load on the lighting circuit?

If I want to calculate the draw on the lighting circuit by the low voltage downlighters, what figure for wattage should I use for each light? Just because they have 50w bulbs I assume because they are using transformers the "real" wattage will be lower. I read a spec. for one of the transformers (aurora AU-60T3), a 60w electronic transformer, which appeared to show it used 0.27 amps. This would suggest that the actual wattage of the downlighter was 0.27 x 240v =

64.8 watts which is in excess of the bulb wattage! Therefore 18 downlighters would be drawing 4.86 amps. The current 9 x 60w bulbs in the kitchen and breakfast area would draw 2.25 amps by my calculations, so I guess 4.86 is still 2.61 amp increase on the already overloaded circuit.

Why would a qualified electrician say that I didn't need to worry about the load on the lighting circuit when switching 9 x 60w bulbs with 18 x

50w low voltage downlighters, without even having checked what the existing load was?

If I were doing this job myself I would seriously consider connecting the downlighters to a different 6A lighting circuit using a spare connection on my fuse box. This would eleviate the current potential overload and reduce it to 1438 watts (5.99 amps) although I believe this is still above the 1152 watts maximum for a 6A circuit when 80% load is assumed (6 x 240 x 0.8).

I would appreciate confirmation that my calculations and concerns are valid.

Paul.

Reply to
Milleniumaire

Diversity is not usually applied to lighting circuits. You can usually assume 1.2kW or 12 ordinary 'points' on a lighting circuit.

Yes.

This is a moot point.

The IEE Regs require lighting circuits to be designed assuming 100W per point minimum or actual load if greater. They don't however define point in any way which is sensible for LV lighting. If you are using separate transformers for each light, then each transformer IMHO should be considered to be a load of 100W. If you are using one transformer for several LV lights, then IMHO you should use the actual load of the transformer >100W - this will be the mains load, not the lighting load. Transformers are not 100% efficient.

There is also the point that circuits should be arranged to minimise inconvenience and danger in the event of a fault. This is an additional reason for splitting your lighting over several circuits.

If he didn't check what the existing load is, he can't say whether the circuit is adequate for the new work.

Why do you think you need to assume 80% load? Unless your lighting circuit has rewireable fuses, in which case it is the cable size which must be downgraded, not the load, i.e. your cable must be rated for 6A x

1.2.

Owain

Reply to
Owain

eh?

ITs a VA rating, but its VA that counts here. Transformers arent 100% efficient so of course the load will be more than the 50w of the bulb,

he's already figured how to address it, or is taking on the risk of more expense with the quote. Or is a cowboy.

With 18x 1500hr bulbs, your average relamping interval is 1500/18 =3D 83 hours. With mains bulbs with a high premature failure rate it would be even more often.

1kW will raise your indoor temp several deg c in hot summers. Fun.

Your floor will be uncomfortably intensely lit, your ceiling dark, making for atrocious light spread. Lean back in your chair/sofa and you'll be intensely and painfully dazzled.

1kW of lighting on 5 hours a day will eat 5kWh/day, 1825 kWh/yr, =A3182 per year just to light 2 rooms! =A35640 in electicity for just 2 rooms in its guesstimated 30 yr life.

Then theres bulb cost as well. =A31 per bulb per 83 hours is 30yrs x 365 x 5 /83 =3D =A3659 in bulbs!

Total cost of ownership for just 2 rooms is then =A36300.

Stop being dense, go back to wifey and say no. Its not healthy if you cant say no, and with unresolved unhappies you'll end up losing what youre trying to save sooner.

If youre determined to have this showbiz tat, choose instead 10w halogen downlighters and make up the light level with cfl uplighting

NT

Reply to
meow2222

I'm not sure how he could have figured this out as he didn't leave the kitchen area so wasn't able to know what light fittings I was using elsewhere or what type of fuse the circuit was using. Of course he could have assumed these things but I found it suprising that he should so confidently tell me that the existing circuit could handle the extra load without investigating what the current load was.

How do you think he would have figured out how to address it from standing in the kitchen?

Interesting information, but you're assuming that cost is an issue for me!

You haven't met my wife ;-) Besides, I've come round to the idea, although I'm not convinced that we need as many lights as two of the electricians have suggested so I plan on calculating the lighting requirements myself.

Paul.

Reply to
Milleniumaire

The 100 W minimum is "per lampholder," which I would interpret as applying to lampholders for ordinary GLS lamps. For a lighting scheme (ELV or otherwise) using luminaires which can only take a specific lamp,

50 W max. in this case, then surely you can base your design on actual connected load - i.e. the input VA to the transformers, 0.27 A or 62 VA per point in this case.

I can't see any reason to do that, when the loading of the fixed installation is 62 VA max.

Agreed, and you must take power factor into account if using 'electronic transformers'.

Reply to
Andy Wade

i thought it was just answered

no, just assuming you could think of something of more value you could get or do for =A36300.

NT

Reply to
meow2222

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