Question about high wattage CFLs

Ross Murphy

We're getting some improvements done in our house (in Dublin), so we're replacing several light fittings and bulbs in some rooms.

I currently have a single 20w CLF bulb from IKEA in my sitting room (produces 1100 Lumens of light), but it's not really good enough (too dull sometimes). I found a 30w CLF in B&Q that puts out 1900 Lumens, but the assistant in B&Q told me I couldn't use it in a domestic light fitting and that a bulb of that wattage was meant for outdoor use.

I don't understand why I can't run a 30w CFL bulb from a light fitting rated for a 100w incandescent. Although the light says it's "equivalent" to a 150w incandescent, surely only the power matters and the 30w CFL will be well below the energy and heat output limit of the fitting. No?

I talked to another guy in the National Lighting Showrooms and he seemed to think I could put the 30w CFL in a 100w rated fitting, but only if it was made of metal and not plastic.

So what's the story? Can I use a large CFL like this in my house?

(Note: here's a link to the bulb I was going to get: http://www.diy.com/nav/decor/lighting/light-bulbs/energy_saving_bulbs/-specificproducttype-globe_bulb/Diall-Energy-Saving-30W-Globe-B22-12418816).

cast_iron

There's no issue using the bulb from a safety point of view.
I think the B&Q person meant that it would simply be too bright. Unless the room is pretty large, a 150W equivalent bulb would be way too bright. At 30W, I don't see the need for a metal BC holder, but if you are getting a new holder anyway, buy the metal one for the sake of the extra euro or so.

Bruthal

As said, no problem using the 30 watt cfl in the standard holder.

Ross Murphy

Ok interesting, thanks for the response guys.

I'll probably go ahead and get a metal 100W fitting and put the big 30W CFL in it then for the front room.

I was also going to get either two of those for the Kitchen (which is a bigger room) which would provide 3800 Lumens of light. Or the equivalent in smaller bulbs, like say 2 triple light holders with about 600 Lumen output each.

I found some nice bulbs like that in B&Q but again the assistant told me that none of their triple light fittings could take the bulbs I wanted to use. I saw some light holders which said they could take a maximum of 3 40W incandescent bulbs, but only 3 9W CFLs (which I think would be too dull). I wanted to put 13W CFLs into the same holder (and it would fit), but she told me that it wouldn't be possible and that it would just blow the hold fitting.

She claimed that all their fittings were very specific and that if I went over the limit that was stated on the box (9W CFL) that it would just blow out. I still don't understand why this would be though, since if the fitting is able to deal with 3 40W incandescent bulbs (120W of electricity and heat) then why can't it deal with 3 measly 13W CFLs (39W total)?

Do you guys think there is any truth in what she was telling me? Or is she just flat out wrong?

(Note: here's the 13W bulb I was going to get for the supposed 9W fitting: http://www.diy.com/nav/decor/lighting/light-bulbs/energy_saving_bulbs/-specificproducttype-candle_bulb/Diall-Energy-Saving-9W-Candle-E14-12418847).

Bruthal

Ross Murphy wrote: »

I saw some light holders which said they could take a maximum of 3 40W incandescent bulbs, but only 3 9W CFLs (which I think would be too dull). I wanted to put 13W CFLs into the same holder (and it would fit), but she told me that it wouldn't be possible and that it would just blow the hold fitting.


Do you guys think there is any truth in what she was telling me? Or is she just flat out wrong?

Did only she say they can take only 9W CFLs, or it said on the fitting carton?

Sounds like rubbish to me anyway. Only physical size would seem a possible reason for not being suitable.

Ross Murphy

Bruthal wrote: »

Did only she say they can take only 9W CFLs, or it said on the fitting carton?

Sounds like rubbish to me anyway. Only physical size would seem a possible reason for not being suitable.

Yeah, the box said something like "MAX. 3x40W inc. or 3x9W CFL".

That just doesn't seem to make sense to me though, unless I'm missing something.

Bruthal

Ross Murphy wrote: »

Yeah, the box said something like "MAX. 3x40W inc. or 3x9W CFL".

That just doesn't seem to make sense to me though, unless I'm missing something.

It could be that they are taking account of whats called power factor. A 9 watt cfl has a power factor of about 0.6 probably, which in laymans terms means that it takes the equivalent current of a 15 watt item.

So it is probably that which accounts for it being on the box about using no bigger than 3 x 9 watt CLFs. Cant see a problem with using 3 x 13 watt CFLs in reality though.

Ross Murphy

Ok, thanks for the advice. I think I'll just go ahead and get those things now and see how we get on.

Bruthal

Ross Murphy wrote: »

Ok, thanks for the advice. I think I'll just go ahead and get those things now and see how we get on.

Yea I wouldnt be too concerned about 3 x 13 watt CFL lamps in them.

They will not cause any problems. The extra current drawn for the bulbs power factor thing is wattless, so only heats the wiring, which will be practically zero in terms of extra heat to the fitting wiring. The wiring rating would be far in excess of the combined wattage of 3 lamps anyway.

And the light fitting ratings are to do with the heat generated by the actual bulbs themselves, so there will not be a problem, as the CFL wont really generate any more than its 13 watts rating.

tomdempsey200

ya

i think the fittings are rated for incandescent use

so if there was such a bulb as a 100w cfl it would be generating less heat than the 100w incandescent

if i'm not mistaken

Bruthal

Id say you would be right there alright.

ted1

If your replacing the fitting with a metal one your probably going to have to run an earth cable as well.

Just a heads up.