Problem with a pendant light fitting

How often is "very often"? How much per day is the light on?

Most incandescant lamps are rated for 2000 hrs you have three so on average you will be replacing one every 2000/3 hrs call it 700 hours.

We have a similar fitting but upward solid glass bowls, I never felt it was overheating that caused shorter bulb life. The rising air next to the bulb will draw cooler air in down the sides of the bowl. Enclosed fittings like bathroom globes are another matter.

Our problem was a rather high mains voltage, it would peak just outside the upper tolerance of 253 V and had an average >245. Only spotted when I bought a UPS and it went straight into "voltage trim" mode... Called the DNO, they came round, measured agreed, and adjusted a tapping on our pole transformer. Volts down to 240 average, bulbs lasted much longer...

Another possibilty for short bulb life is vibration, though if you are using 40 W candles they are pretty robust compared to higher wattage lamps. Is the floor/ceiling a bit springy?

It is a hot enviroment maybe the contact in the base of the fitting has lost a bit of it's springyness, try levering it up a bit. Also give ita bit of scrape to remove any oxide. Power off of course... B-)

Is the threaded part metal or plastic with another bendy bit of metal to make contact? If a bendy bit of metal adjust that so it will make contact with the lamp base.

Take the fitting down, clean up the contact surfaces, make sure wire pinch screws are done up properly, refit.

Filament lamps are normally 1000hr rated, so you should be replacing one every 333hrs of use on average. Xenon ones are generally 2000hr rated, so one every 667hrrs.

Bare CFLs look particularly bad in chandeliers, but if they fit and are covered by shades they should do fine, and last 10x as long.

NT

Getting at the spring in the bottom of a SES socket is going to be hard, I think, especially to pull it 'upward' a little.

The bulbs look outwardly like old-fashioned filament bulbs but are actually a small halogen bulb mounted inside a globular enclosure. They're rated at

For a year or two I've been recording when I change a bulb, and in each case which position in the group is being changed, and have noticed that I'm doing so significantly more often. I don't have a ohm-meter at mum's house though so don't verify that a non-functioning bulb is actually blown, but do usually check that slightly tightening the bulb in its socket doesn't make it suddenly work. It's possible that some/all times I haven't checked the bulbs have been ok and just replacing them made a better contact.

Recently bulbs have lasted as little as 3 weeks, though around 4 months seems more usual. Some have lasted around 9 months.

The bulbs I'm using are eco-halogen, 45mm diameter, 78mm length, E14 (SES), that look like:

The cone/shade is very narrow and after candle-shaped bulbs ceased to exist (in local shops at least) I thought we were lucky to find the eco-halogen things.

is that "eco-halogen" a.k.a "halogen"?

Probably. I guess it's just marketing speak to make what looks to a casual glance like a normal globular filament bulb seem special in some way. OTOH I did see the term quite a lot while googling on the topic.

It seems theyre really xenon, not halogen

NT

With the fitting still on the ceiling yes but not on the table. Might need a bit of stiff bent wire to hook under to pull upwards. Hasn't Aldi got a set of spring hooks on offer from Thursday? Yes, they do £2.99 set of four but probably too big for this application.

Per lamp, you have 3 so divide that 285 by 3 = 3 months

The "4 months seems more usual" is close enough to a 3 month average. We had two fittings with 3 lamps each, that really was a lamp every month until we got the voltage sorted out. That did improve things but we switched to CFL not that long afterwards and almost forgot how to change 'em. B-)

Halogens are fragile particularly when hot.

I might get away with a bit of massacred coat hanger...

No, I don't think so. I think you're saying that on average one would replace a bulb every 3 months, which I agree with. But any individual bulb should still last approx 9 months surely?

If a bulb only last 3 months, then I'm getting 90 days * 7 hours = 270 hours out of it, not 2000 hours.

I've not just recorded how often I change a bulb, but instead when I change the bulb in fitment 1, when I change the one in #2, and when I change the one in #3, so I know the length of service of each bulb.

Do they blow on switch-on or "in service"? If it's the former you could fit a dimmer switch to start them up gently. You need the type where the on/off switch is part of the rotary action, not the push/pull ones.

Chris

halogen is a generic term for certain gasses, xenon is one of them.

Bit of confusion between Halogens and Noble gasses, methinks.

I'm not a chemist.

months.

True, I hadn't picked up on your record keeping being per lamp rather than "I only did that last month" across the fitting.

I'd clean and rebend the contacts, monitor the supply voltage when the light is in use and, as these are halogens, see if there is vibration being conducted down from the floor above.

Halogens = Fluorine, Chlorine, Bromine, Iodine (and the practically non-existent Astatine).

Noble gasses = Helium, Neon, Argon, Xenon, Krypton and Radon.

But is seems a combination of halogens and noble gasses are used in 'halogen' lamps ...

am I correct in assuming that the "noble" ones can't cobmine with other elements to make an alloy?

At a "lies to schoolboys" level, yes ... you probably mean compound rather than alloy (which only applies to metals). In fact rather than never forming compounds with other elements, the noble gasses are merely "extremely unwilling" to do so.

They're otherwise known as the inert gases, so yes, they have trouble combining with other elements to form compounds. It has to do with them having a fully filled outer electron shell, according to my chemistry teacher in the 1970s.

There are a few interesting ones, though, mostly involving Flourine, which is *extremely* reactive.

i did debate with myself whether "alloy" was the right word to use. to me "compound" doesn't imply the same degree of combining.

Compound implies a much closer mingling and more interaction of elements than an alloy. Alloys tend to be microscopic grains of individual metals with little or no chemical interaction between them, while a chemical compound combines the elements on an atom by atom basis.