Triple spotlight: bulbs blowing in one of the fittings

[tabbypurr]

220v bulbs have a life of about 300hrs ave on 240v, so it's not that.

NT

[tabbypurr]

not at 100 times a second you won't. It kills bulbs.

NT

[tabbypurr]

230v filament lamps don't even exist. Harry as always!

NT

[Bert Coules]

I hadn't realised that the cycling would be that rapid; thanks.

[Harry Bloomfield]

You are of course very wrong. Any lamps intended for most of Europe are manufactured as 230v. At one time in the UK you could buy 210, 220, 230 and 240v lamps. The reason being the variation in local distribution voltages and filament lamps sensitivity to voltage.

[tabbypurr]

Come back when you know your subject

NT

[Harry Bloomfield]

I do know my subject, but it is obviously a waste of time attempting to explain that subject further to you.

I always check the voltage markings on lamps I purchase, to ensure they are 240v intended for the UK market, because I often see 230v ones intended for the EU on sale in the UK - FACT. Yes, I have been caught out a few times. These last no time at all and are not worth the effort of installing them.

Back in the pre 1960's you could certainly buy a variety of lamps with voltages 210, 220, 230 and 240v. Checking the voltage required was as important as checking the wattage of the lamp required - FACT.

[Harry Bloomfield]

You sir are an idiot! Switching on and off 100 times per second is normal operation on a/c mains.

[Harry Bloomfield]

You are making it up as you go along.

[tabbypurr]

Shaking head here. Enjoy your bulb purchasing.

NT

[tabbypurr]

Reputable testing indicates otherwise.

It's when a poor connection switches on & off 100 times a second that filament lamps die early. Could you not work out that that was the point?

NT

[tabbypurr]

Something tells me you're unfamiliar with the equations that apply to filament lamps.

NT

[damduck-egg]

After WW2 National service until he decided what work would best suit him to my Dad assisted a buddy was starting a small electrical business. In the end Dad decided to follow another career but a remnant from that short stint was a carton or two of lamps. All standard bayonet connection mainly around 40 Watts. All were the same size physically Voltages marked on them were 12 ,24,50, 100, 200,through to 250 although by the time I got to rifle through the boxes anything left for 200 and above was coloured not clear which had been used. Reason for having the variations is post war the mains was only just arriving in the area but a lot farms had their own generators supplying different voltages. Over my growing up years I got through most of them ,making up fittings that held lamps in series for use in Dads sheds or 12V inspection lamps for use with vehicles or in my first road legal vehicle an A35 van a decent interior light in the back. The lamps were fitted into a fitting designed to hang in a shop window as a Black and Black advert so that was double DIY points.

The coloured ones above 200v were used up in the outside Loo where visitors got used to it having a green or orange light and for a period blue thus predating public bog attempts to deter drug users by

50 years.

G.Harman

[charles]

At Cambridge, at the end of the 50s and early 60s, mains was 200v.

[Bert Coules]

Update: the known-to-be-good bulb taken from a different room and put into the possibly-suspect fitting is still going strong after several days. The new bulb from the possibly-suspect batch put into a known-to-be-OK light fitting is also still burning bright.

Conclusion: several (but not all) of the bulbs in the Homebase box-of-six had, for whatever reason, a very limited life span. There is nothing amiss with the suspected fitting or the wiring feeding it.

Thanks to everyone for the thoughts and suggestions.

Bert

[ARW]

That is IMHO the most probable answer.

[pamela]

That's interesting and I read more details in the FAQ.

240v

I was almost certain that all my light bulbs are marked 230v but when I get a moment I must check them!

[Mike Clarke]

As a child in Huddersfield in the 50's I remember that it was important to say what district you lived in when buying a lamp bulb because there were different voltages in different areas of the town. Eventually it was standardised and I remember men coming round from the electricity board replacing lamp bulbs and the elements in cookers, electric fires and irons. I think they also changed the motor in my Mum's vac.

[Fredxxx]

Nope, it is possible still to buy 240V lamps.

230V is the EU standard for supply and the supply in the UK is still 240V which of course is within tolerance.

[tabbypurr]

All UK mains filament lamps are 240v, barring any odd specials eg for railways etc.

Yep. But don't tell Harry.

NT