I think our house gets through too many lightbulbs...
The final straw was this morning. I went to turn the kitchen light on and it blew a bulb and tripped one lighting circuit out. I went to put the lounge light on to go and reset the switch and a bulb in there blew too, tripping the other lighting circuit out! That's just too much of a coincidence. Has anyone heard of a problem which causes this to happen?
BTW, this is a very old house, no idea how old the wiring is but we had to have it surveyed when we moved in. The survey showed no problems.
I've had bulbs blow in succession. It's just one of those things. The only thing that would make bulbs blow more quickly than they should is excessive voltage and you haven't got that have you? They may be inferior bulbs, I suppose.
Try writing down the date you install each bulb and you might be surprised to find how long they actually last.
Get or check yourself what the supply voltage is. Current spec is 230v
+10% -6% (216 to 253v) the peaks should not go outside of that range. You will need to monitor the voltage as it can vary substantially through the day and night.
If you do find readings on the high side it might be worth complaining to the network supplier for your area and explain your readings and light bulb problem, record when you change each bulb as well. They'll probably come along and fit a monitoring device for a few days if their measurement doesn't reflect a problem when they first visit.
Replace your lightbulbs with compact fluorescent types. These don't blow so regularly and don't needlessly pollute the environment to anything like the same extent. Also, when they blow, they do so gradually and don't tend to take the MCB with them.
Christian.
P.S. I had exactly the same experience as you a few days after moving into my new house and before I had a chance to go down B&Q for some more decent bulbs. Rather freaky, really, but statistically not that unlikely, as they blow so frequently.
I used to live in a house where the electricity was supplied by overhead wires direct to the house and it was forever blowing bulbs. Our neighbour even managed to get a washing machine replaced by the electricity company.
Unfortunately a few brands can't quite survive the maximum 253V and die as soon as you plug them in. But B&Q were very sympathetic and replaced all four.
It may be just coincidence. Dampness does make them go. Corroded bulb socket contacts also can cause this.
As far as investigating the cause goes I wouldnt do much beyond check the bulb sockets are OK, since this is just part of life with incandescent bulbs.
Wire fuses are much better than MCBs for lighting circuits since they dont pop when the bulbs do, whereas MCBs are just a nuisance. And nuisance tripping on the lights is a known safety issue. With some installs you can replace MCB with wire fuse quite happily, and with some thats not true.
I try to move over to CFLs when possible, solves several minor issues in one stroke.
So they should. A non incandescent bulb that can't survive 230V +/10V surely fails to meet specification. (Incandescent bulbs come under specific different rules).
Its standard in winter - espceially early winter - when all the light bulbs that are just on the point of failing get a combination of cold, and extra high mains voltage just as you start to switch them on...becasue the grid is run up a little high in anticipation ofteh evening load...I expect to lose maybe 10-15% of small mains volrtage bulbs this month ...I just carry large stocks and keep replacing em as they go.
Yes. If you have an old supply as I did, the pole mounted transformers are very poor on regulation, and its normal to find significant over voltage under low load, and under voltage on high load.
If you can demonstrate the mains is out of spec sypu may be able to get a newer one free.
You're not buying them from Poundland are you? I bought some a while back. They not only didn't last, but when they failed they blew up and scattered glass all over. Trouble was I couldn't remember which ones I'd replaced with them so it was just a question of waiting with head slightly bowed until they all finished. ___________________________________________ Peter Scott We elect politicians to run the country, not our lives ____________________________________________
15 cycles would be pushing it in my book. But I take your point that I did not define "peaks", I'm really thinking of what an analogue volt meter would read rather than any instantaneous voltage.
The regs. have changed, primarily to create a 'single market' in light bulbs.
UK mains voltage was defined as 240v +/-5% but is now officially 230 -5%
+10%. The actual voltages have _not_ changed, as 240V is within spec (you couldn't change it in any case as you'd risk damaging some existing appliances), BUT the change of official standard now allows continental
230V bulbs to be sold here as 'fit for purpose'.
If you have 230V lightbulbs, that means they should, on average last, for their rated time at he rated 230V supply. As the voltage increases above 230V, their life dramatically shortens. I forget the formula now, but IIRC, it's at least exponential.
The problem arises when your existing mains voltage is on the high side. As you can see it could be as high as 253V legally (previously only 252V was permitted), but now, the discrepancy between the bulb's rated value and operating voltage can be that much greater.
I have the same problem here. Our mains is often up to 252.5V RMS, and whereas previously the local supplier would have been required to change the tap on the local substation (once evidence was obtained with a recording voltmeter), now they can just laugh at you (and ours did).
I've been reduced to buying 60W bulbs in large quantities from Screwfix. They're so cheap it offsets the problem somewhat, but changing them is still a pain.
Look at my sig if you can't work out who to blame...
I was under the impression that incandescent lightbulbs were exempt, as they are fundamentally voltage sensitive. UK lightbulbs are designed for 240V, not 230V.
I'm not sure what 'exempt' means in this context. If it means you can still buy 240V bulbs, yes that's true. I don't know the current status of 230V bulbs from the continent, but will investigate.
I mean that bulbs are still sold for the actual local line voltage rather than the nominal 230V and are not required to cope with the full voltage range likely to be experienced across Europe. A French lightbulb will be designed for 220V. A UK lightbulb will be designed for 240V.
"Christian McArdle" wrote | > I'm not sure what 'exempt' means in this context. If it means | > you can still buy 240V bulbs, yes that's true. I don't know | > the current status of 230V bulbs from the continent, but will | > investigate. | I mean that bulbs are still sold for the actual local line voltage | rather than the nominal 230V and are not required to cope with the | full voltage range likely to be experienced across Europe. A French | lightbulb will be designed for 220V. A UK lightbulb will be designed | for 240V.
I think it likely that a court would hold that mains lightbulbs sold retail in the UK should be fit for the purpose of being used in the UK, regardless of whether the bulb is marked with the European nominal 230V or the actual British 240V on the box. Otherwise Mrs Housewife has no protection from cheap imports from Poland or wherever.
This might not apply to industrial supply where a range of voltages is used and where the purchaser can be expected to be more technically knowledgeable.
I see. I'm not sure about this and will investigate further.
It remains the case however that, for practical purposes, as I have discovered to my cost, UK mains voltage can now vary through a greater range than before. A line voltage of 252V RMS does shorten the lifespan of light bulbs significantly, and the relaxed tolerance is a direct result of the legislation.
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