Lights Blow After 5-6 Weeks

[wadia860]

Hi, any advice would be greatly appreciated. We live in an old terraced house (you can see where this is going!) and we have 3 lights covering the stairs and landing.

We used to have the standard UK bayonet light bulbs and these would blow after about 5 or 6 weeks. They were then changed for the longlife GU10 type bulbs, these still blow after roughly the same period.

I think our house is a hazzard but can anyone give me an idea or explanation as to why this is happening please?

TIA

 

[Steve]

We used to have the standard UK bayonet light bulbs and these would blow after about 5 or 6 weeks. They were then changed for the longlife GU10 type bulbs, these still blow after roughly the same period.

GU10? Are you sure you dont mean CFL? GU10 would require a different fitting.

GU10:

CFL:

 

[sparkyspike]

It's unlikely to be a wiring fault. 'Long life' bulbs are a bit of a con as they don't usually last as long as they say. Vibration is one reason why GU10s blow - for example, if they are beneath a staircase or kid's bedroom.

Another reason is CHEAP LAMPS! What brand do you use? I find that Osram and Philips seem to last longest.

 

[wadia860]

GU10? Are you sure you dont mean CFL? GU10 would require a different fitting.

GU10:

That's the fellas! The fittings were changed as well!

Thanks for the replies, I'm not so sure about the brand but they quoted an average of 6000 hours. I feel that 10 minutes here and there over 6 weeks cant add to to 1000 hours let alone 6000 hours!

I forgot to add that the consumer unit trips out when the bulbs blow. Thanks again for the replies.

 

[sparkyspike]

It's normal for the RCD to trip when a lamp blows. Also, when a lamp is rated at 6000 hours, or whatever, this doesn't allow for turning it on and off for short periods, or for other factors such as heat and vibration. This will reduce its life dramatically. A new lamp can blow instantly if it's been dropped at some point in the store, so the hours on the box can only be used as a relative guide.

 

[Steve]

Its normal for the MCB to trip when a "bulb blows", especially on cheap bulbs. There is a surge through the lamp when the filament opens.

Normal life on GU10s is about 1000-2000 hours. A 6000 hour lamp should get noticably more life.

Do you own (or are you able to access and use) a multimeter to test voltage? Normal UK voltage is 230-240 volts, BUT it can vary anything from 215-250 volts, this is the acceptable tolerance. If you're getting near 250, this could be the problem. If you're getting over 250, you have a case with your supplier to correct the fault.

Vibration can also kill filament lamps.

Out of interest, CFLs are practically immune from all the above

 

[Steve]

It's normal for the RCD to trip when a lamp blows.

Is it? How would an RCD open from a fault between live and neutral?

 

[wadia860]

Thanks everyone...Steve, I have a multimeter but I'm not sure how to use one!!!

 

[ban-all-sheds]

Click

 

[Steve]

My guide to using your multimeter to test voltage:

1. Turn off power.
2. Open a socket.
3. Once you are satisfied all the cores are gripped by the terminal screws and there are no loose cores etc, restore power.
4. Set your multimeter to volts AC ~. If it wont autorange, set it at above 300 volts.
5. Touch one probe (red) carefully to the live terminal, and the other (blacK) carefully to the neutral terminal.
6. Now read off the voltage. (its best to do this probing whilst the MM display is hanging in view without having to hold it, or grow a third hand) Note the voltage may display negative, if you have your probes reversed. This is fine, its the same voltage positive or negative.
7. Replace socket, isolating power first if you wish.

NOTE: the above is only for people who are comfortable probing live wires. Be very very careful - 230VAC can, and will, kill.

If a strange or fluctuating voltage appears, you have selected volts DC. If your multimeter explodes, you have selected something else entirely.

 

[ban-all-sheds]

Set your multimeter to volts AC ~.
.
.
.
Note the voltage may display negative, if you have your probes reversed.

 

[Taylortwocities]

 

[sparkyspike]

It's normal for the RCD to trip when a lamp blows.

Is it? How would an RCD open from a fault between live and neutral?

There is a surge through the lamp when the filament opens.

 

[RF Lighting]

That wouldn't trip an RCD.

Although there is a large current draw as the filament fails and forms an arc, the line and neutral currents will still be balanced.

 

[Adam_151]

It is theororetically possible for a failing lamp to trip an RCD, I've never personaly seen it happen, but others (including those who *do* know the difference between an RCD and MCB*) have reported seeing it happen

... that will have got crafty thinking