Bulbs popping

[Multiplex]

I'm finding my bulbs keep popping after just a few weeks....now I changed them for energy savings bulbs from Maplin (made by Luxx) with 8000 hours life, and I've just had one go after 4 weeks!

What's the point of paying extra for an energy saver when it goes just as quickly as a normal light bulb? I kinda thought these bulbs were more resistant to expiring than tungsten!

Simon.

 

[ban-all-sheds]

What's your supply voltage?

Are you buying 230V lamps, or 240V?

 

[Multiplex]

The bulb:

Luxxx
15W 108mA
220-240V 50/60hz

I thought all UK supplies were the same? I'm connected to Seeboard, but I can't find the supply voltage on their site...

Is it just one of those things or is there a problem somewhere? At 3 quid a bulb I thought I was avoiding cheap rubbish!

Simon,

 

[Damocles]

Bulbs going frequently might possibly be a sign of your having an excessively high mains voltage. Mains voltage can vary due to problems with the network. Or that someone is nicking them and putting in dud ones? Or you flick them on and off a lot? Or you actually have rather a lot of bulbs in normal use, which might mean that could expect to change a few each month.

Do your neighbours have similar problems? Are you right next to a substation transformer? Do you have the only supply in the middle of nowhere? Is every third house in the street affected?

 

[uselessFCUK]

If the lamp goes again in the same fitting, you have been given a clue of where to start checking.
Is it a Bayonet lamp fitting? One of the pins may be worn. Are they sprung?

Is it an Edison Screw fitting? Check the center connector is in tact.

 

[plugwash]

also in my experiance old switches can kill lamps though im not exactly sure why this happens.

 

[IanSF]

In addition to the OP, I am having to replace popped bulbs all over the house every 4 months or so. In the year that I have lived here I must have replaced every bulb in the house at least once. This is in a house that is newly built.
What puzzles me is that the MCB trips every time a bulb fails at switch on. Why does a bulb failing cause a current surge enough to trip the MCB?

 

[Damocles]

Oh that is an easy one. It is because they are designed to switch off when a bulb goes. Damn fool idea. I am presuming that you have type B 6A mcb. Some people design circuits which do not do this, using either type C or 10A circuits.

It is because there is a very large surge current when a bulb blows. It effectivly short circuits the terminals inside the bulb for about 1/100 of a second. The 6A type B are inadequate to carry this, and trip.

Do you leave all your lights on for 3 hours a day? If so, you would expect each one to fail once a year quite normally. (1000 hours lifetime)

 

[laurence1976]

This may sound silly to most people and prob a load of rubbish but its widely known that supernatural activity can drain the power from any battery operated appliance or even ight bulbs, could you be sharing your house with an unwelcome visitor? Just a thought.....

 

[ban-all-sheds]

The bulb:

Luxxx
15W 108mA
220-240V 50/60hz

I'd not thought about the fact that they're CFLs - they probably can genuinely work OK over a wider range of voltages. The reason I asked is that it's (probably) a little known fact that at 240V (what our voltage really is) a lamp rated at 230V (what our supply nominally is) will only last 50-60% as long.

I thought all UK supplies were the same? I'm connected to Seeboard, but I can't find the supply voltage on their site...

For many years the supply voltage for single-phase supplies in the UK was 240V +/- 6%, giving a possible spread of voltage from 226V to 254 V. For three-phase supplies the voltage was 415 V +/- 6%, the spread being from 390 V to 440V. Most continental voltage levels have been 220/380V.

In 1988 an agreement was reached that voltage levels across Europe should be unified at 230V single phase and 400V three-phase with effect from January 1st, 1995. Those countries with a nominal voltage of 240V (like the UK) were obliged to move to 230V +10% -6%, and those on 220V moved to 230V +6% -10%.

It was proposed that on January 1st, 2003 the tolerance levels would be widened to ±10%, and then that was pushed back to 2005, and then in July 2001 the CENELEC Technical Board decided to continue with the existing tolerances until 2008.

In any event, the European-wide harmonisation is not being done by having common supply voltages, but by requiring manufacturers to make products which operate over a much wider range. Since the present supply voltages in the UK lie within the acceptable spread of values, Supply Companies are not intending to reduce their voltages in the near future. This is hardly surprising, because such action would immediately reduce the energy used by consumers (and the income of the Companies) by more than 8%, although when the system is under heavy load the generating companies happily take advantage of the lower limit

Is it just one of those things or is there a problem somewhere? At 3 quid a bulb I thought I was avoiding cheap rubbish!

£3 each is pretty cheap - I've no idea if Luxx are rubbish. It might be an idea, if you have anywhere where there are 2 or more luminaires on one switch, so that you can guarantee identical operating conditions, to try putting in a new Luxx and a new lamp from Philips or Osram or GE and seeing if they last the same amount of time.

 

[Scoby_Beasley]

Do you leave all your lights on for 3 hours a day? If so, you would expect each one to fail once a year quite normally. (1000 hours lifetime)

Aaaah, this explains why I change bulbs (what seems like) daily. It's my 16yr old daughter trying to improvise her own mini Blackpool !! She seems to think lightwitches only go "on" and the light fairies (or is that fairylights ?) turn them off when she isn't here, gawd bless her

 

[Multiplex]

Just to make you laugh (and I'm not making this up!) the replacement bulb (another Luxx off the same batch) lasted just two days!!

This light is switched on once at 5pm and goes off at 11pm with no switching in between. I'd like to think it's the bulbs in this case...but as I said I thought these weren't cheap ones. Although they were on special offer from Maplin!!

Btw, this is a new house too and it also trips the MCB when the bulbs pop...

Simon.

 

[andy]

Btw, this is a new house too and it also trips the MCB when the bulbs pop...

Simon.

its susposed to.

 

[Damocles]

My guess is that it was a bit of a screw-up by the people responsible for introducing mcb. The old 5A rewireables do not have this problem because it takes a lot more energy to melt the wire than it does to initiate a trip in a mcb. A mcb is designed to switch off very fast if a certain threshold current is passed. Even though the big current stops very quickly without any risk of damage to the circuit, the breaker still trips.

The designers probably wanted make things easy so they specified mcb for household use all with the same characteristics-type B. And circuits at only 6A, so they were compatible with those already installed in most houses.

Which is all tickety boo, except that the mcb are really a step backwards in useability. It is actually another regulation that circuits should be fit for the purpose and should provide discrimination. Which means that when perfectly predictable and frankly normal events occur, you should not loose all power everywhere. So it in fact contravenes regulations to design a lighting cicuit which trips off every light when a simple bulb fails.

So people still fit 6A type B as standard, because you can never be held at fault if you do it by the book, can you?

 

[plugwash]

agreed for lighting cuircuits a B6 is just too low

B10 and C6 seem ok though.