Multi globe light fittings

[Tool-Horder]

Can anyone suggest a technical (or maybe a BS) answer as to why incadecent globes dont last as long in multi globe light fittings? I also find that once one goes the rest soon follow suit. It seems to be the nature of the beast to do this as everyone I know has the same problem. Yet two fittings wired on one circuit don't seem to suffer the same fate.

[Smurf]

Can anyone suggest a technical (or maybe a BS) answer as to why incadecent globes dont last as long in multi globe light fittings? I also find that once one goes the rest soon follow suit. It seems to be the nature of the beast to do this as everyone I know has the same problem. Yet two fittings wired on one circuit don't seem to suffer the same fate.

If they are in the same enclosure and thus it is getting quite hot then that will shorten the life of the globes a bit.

Anything with vibration such as ceiling fan lights, garage door opener lights, suspended light fittings subject to strong breezes (open windows, fans, air-conditioning), lights mounted under a wobbly floor (2 storey etc) will also shorten the life of the globes.

I know that traffic lights etc and other places with a lot of globes have trouble with large numbers failing at the same time. It happens after strong winds and also during Spring when power demand drops (this is in Tas where heating is big user of power) thus voltage comes up a bit.

I've seen quite a few "globes blowing" mysteries though that were never really explained. One funny one though turned out to be a pet bird perching on the light fitting and pecking at one of the globes - not enough to shatter the glass but the same globe kept blowing all the time.

[nev25]

Are they the same globe
IE same base (not the smaller base)
Are they ES or BC

Incidental we have been told as from the end of next year incandescent globes will no longer be allowed to be sold in Australia

[bsrlee]

It will be interesting to see the new Govt. try to enforce this as there are a LOT of applications where the fluro fittings don't work - bathroom heaters & outdoor flood lights to name 2. Plus in areas with high rates of on/off, the manufacturers of the fluro lights claim this stuffs the electronics - and the fluro's use MUCH more materials, so MORE energy wasted plus landfill.

Traffic lights are gradually changing over to LED arrays - at $100's per light. LED replacements for brake lights are available - around $25 each.

[OLDPHART]

Try soldering all the terminals together rather than just twisting, them had this problem years ago this solved it,got sick of buying globes and keeping Woolies profit margins up.
May not work for some,but old sparkys hint.

[Smurf]

Incidental we have been told as from the end of next year incandescent globes will no longer be allowed to be sold in Australia

I've been aware of this for a while but can't get hold of the details (and believe me I've tried...).

OK, so household incandescent globes are out.

What about halogens? They aren't that much more efficient than incandescent. IMO it's the 50 Watt halogen downlights that are the real household lighting power guzzler - nobody had a dozen incandescents in their lounge and six in the kitchen.

What about self-ballasted mercury vapour (used in some commercial / industrial applications)? They too aren't too efficient.

What about coloured party light globes, coloured PAR 38 flood lights etc? Suffice to say I'm particularly interested in these in view of my rather large Christmas light display. Fluoros won't like being switched on / off 100 cycles per minute...

And what about special purpose globes? For example traffic lights (still quite a lot of incandescents around, I work in this industry, and the lights themseves have a 30 year life span). At work we're planning to stockpile incandescent lamps assuming future non-availability. These are special long life (8000 hour) 67 Watt ES globes. Also a few 100 Watt for the larger signals.

I assume heat lamps (Tastic etc) will still be available? A fluoro defeats the purpose there.

Off topic but I see that my new fridge (unpacked it today) seems to have a non-incandescent light. It's very white but I haven't checked out what it actually is. Assume it's LED or perhaps a halogen with a blue filter. It's a Kelvinator 2 door fairly "normal" fridge.

[elkangorito]

Inkeeping with the OPs initial post, I will hazard a "guess" & say that arcing may have something to do with the reduced lamp life. Lamps close together (low impedance between each other) may suffer the transient effects of one of the filaments open circuiting, causing a small arc. This conceivably could affect the other lamps. Why doesn't this affect other lamps on the same circuit? Higher "Impedance" is my guess.

As for what lamps will or will not be permitted in Oz soon, I have no idea. It seems apparent though that all general service incandescent lamps will be unavailable. The term "general" means quite simply any "normal" lighting lamp that does not have a special purpose &/or has a short life. Again generally, most incandescent lamps have a life of about 1 000 hours. Unless these lamps have a special purpose (ie heating etc), my guess is that they will be discontinued from sale.

Is there a document somewhere that is more specific about this?

[nev25]

I've been aware of this for a while but can't get hold of the details (and believe me I've tried...).
.

Yeah apparently the Government made a broad statement earlier this year and didn't give anymore details.
I personally think its a crock of s**t like the statement that was made a few years ago that every house in Australia had to have RCDs (safety Switches) fitted by the end of 2006 or the service would be disconnected

[BobL]

If they are in the same enclosure and thus it is getting quite hot then that will shorten the life of the globes a bit.

Anything with vibration such as ceiling fan lights, garage door opener lights, suspended light fittings subject to strong breezes (open windows, fans, air-conditioning), lights mounted under a wobbly floor (2 storey etc) will also shorten the life of the globes.

This is the correct reason. After some use, tungsten filament filaments in incandescent globes become very brittle and even small vibrations cause them to fracture but maybe not break - next time you switch them on POOF!
I replace the 60W'ers in the ceiling fans in our bedroom maybe 3 times a year whereas the ones in our kitchen last for 2-3 years.

Also did you know that fluoro tubes side by side produce less light than if they separated by a couple of feet. The increased heat makes them less efficient.

[Bloss]

I've been aware of this for a while but can't get hold of the details (and believe me I've tried...).

See: http://www.malcolmturnbull.com.au/Pa...le.aspx?ID=672

and

http://www.environment.gov.au/commit...ons/lamps.html

Not anything more than a media release of an intention to act - no legislation yet. This will be up to the new government (the Minister for Environment Peter Garrett) to follow through - or not.

But heat and vibration are what weaken the filaments of your bulbs as others have said.

[aussiecolector]

I think one of the biggest problems is that the low wattage bulbs used in these fittings have finer filaments and therefor break more easily They are also less efficient, ie one 100w bulb will put out more light than four 25w bulbs.

On the down light subject, I have found some 3w led down lights which put out about 1/3 the light of a 50w halagan.

[Smurf]

I replace the 60W'ers in the ceiling fans in our bedroom maybe 3 times a year whereas the ones in our kitchen last for 2-3 years.

Also did you know that fluoro tubes side by side produce less light than if they separated by a couple of feet. The increased heat makes them less efficient.

Damn!

My new house has a ceiling fan with a light on it and the location in a living area which also has a wood heater (which doesn't have an internal fan) is such that the fan will get lots of use year round. And it's the most heavily used light in the house by far too (only room that doesn't get the sun).

Looks like I might have to get a big box of spare globes...

As for the tubes, not only the brightness but also running them hot causes a strange failure situation where they stay lit but become very dim at the end of their (shortened) life and then get even hotter. I'm not sure if the triphosphors do it but the old Australian made halophosphate tubes did.

I've never understood how exactly that occurs, as in what happens to the tube to make it behave like that, but it's fairly consistent with certain styles of twin domestic diffused battens.