Bottoms up ... or down?

[Taffycat]

I was wondering whether anyone would know why some light bulbs "should only be fitted base up" or, in some cases "base down" in light fittings?

I am mainly referring to good ol' incandescent bulbs and specifically a golf ball 60 Watt.

One of our light fittings takes the above, so I was just hunting through the Amazon wastes to find one of these elusive jobbies. Found some, but it clearly states that the 60 Watt version should only be used base-down.

Our current bulbs, which have resided in the fitting for at least a year, or more, are all base up, and seemed to work without problems. So, I'm wondering why the orientation should matter?

Do any of you electrical boffins know please?

Oh and yes, I know there are lots of energy-saving bulbs out there, and we use them here and there. They just don't look "right" in some fittings - and the light quality is not the best either, purely from a very personal point of view, of course.

 

[Anon_F]

TC, go back to the cat knip or the sherry dear.

 

[muckshifter]

You can wire bulbs anywayround ... the base of the bulb is usually negative (black wire) with the side of the bulb positive (brown wire, red if old wire is used)

the use of incandescent bulbs is, I believe, banned in the EU for commercial use ... Ikea will have an alternative, I have some really nice 'bulbs' from them.

 

[TriplexDread]

The reason the higher wattage should be base down is simple

Heat, after a while the fittings get brittle. With the lap upward the heat travels up and out of the fitting rather than hitting the fitting itself first. It does of course take quite a few years for the bases to become brittle but they do

The energy saving ones don't become as hot.

Use a light chart to decide which is best

 

[muckshifter]

... oh! I get what you were asking now.

It doesn't matter, the Earth spins, so some of the time they be upsidedownrightwayup ... unless you from downunder, then they'll be rightwayupsidown.

 

[Taffycat]

Thank you for your replies, kind sirs!

@TriplexDread thank you for the explanation, it makes more sense to me now. That temperature scale chart is really helpful too. Some of the low energy bulbs seem to give off either a horribly dead, white light, which makes everyone look as if they've been recently snogged by a vampire; or, at the other end of the scale, the light seems a bit "miserable." (Perhaps we've just been unlucky with our brand-choices.)

@muckshifter well interestingly, the ban by the EU, does not cover bulbs which are intended "for industrial use." So some manufacturers are using this loophole to continue to supply incandescent bulbs to anyone who wants to purchase them. (Particularly some of us migraineurs who find them more comfortable.) Just for info:

At least two British manufacturers are now mass-producing so-called “rough-service” incandescent bulbs, which are available in bayonet and screw fittings and look almost identical to – and work in exactly the same way as – the bulbs that will be outlawed.

Manufacturers are allowed to make and sell the incandescent bulbs if they are described on the packing as “rough-service lamps” that are not for domestic use.

Source: The Telegraph (albeit a slightly old-ish report from 2012.)

 

[nivrip]

I like a bit of rough.

 

[TriplexDread]

I like a bit of rough.

PMSL