My light fitting melted - oo-er!!

[Dave P]

I found my bedroom light bulb had failed yesterday - it's a standard bayonet fitting below a ceiling rose. However, it wasn't as simple as just changing the lightbulb - the bulb had fallen out of the fitting. Inspection of the socket showed that it had largely melted, in fact one of the two metal spring-loaded electrical connection pins had dropped out, covered with burnt plastic and melted lead from the bulb contact. The bulb had fallen out because one of the socket cut-outs, which retain the lugs on the bulb, had just disintegrated or melted with the heat.

It sounds like I was lucky not to have a house fire, wasn't I (or not?)? Why would this happen? Why didn't the relevant MCB on my CU trip (they seem to do so - irritatingly - every time a bulb in the house blows!) The fitting was only about 4 years old, is wired perfectly OK, and it's months since I''ve changed the lightbulb which has worked perfectly ever since. I find it pretty scary to think what migh have happened, and I haven't a clue why.

Thanks Dave

[Dave Fawthrop]

| I found my bedroom light bulb had failed yesterday - it's a standard bayonet | fitting below a ceiling rose. However, it wasn't as simple as just changing | the lightbulb - the bulb had fallen out of the fitting. Inspection of the | socket showed that it had largely melted, in fact one of the two metal | spring-loaded electrical connection pins had dropped out, covered with burnt | plastic and melted lead from the bulb contact. The bulb had fallen out | because one of the socket cut-outs, which retain the lugs on the bulb, had | just disintegrated or melted with the heat.

A bad contact generated enough heat to melt things, but did not draw enough electricity to trip anything. | | It sounds like I was lucky not to have a house fire, wasn't I (or not?)? | Why would this happen? Why didn't the relevant MCB on my CU trip (they seem | to do so - irritatingly - every time a bulb in the house blows!) The fitting | was only about 4 years old, is wired perfectly OK, and it's months since | I''ve changed the lightbulb which has worked perfectly ever since. I find | it pretty scary to think what migh have happened, and I haven't a clue why.

I have changed to energy saving ?bulbs?, long ago, so changing them is a very rare occurrence. Also because they use less power they do not run anything like as hot. I have a bad contact in my bedside light, which I must change sometime, but as it only uses 7 watts it is never going to burn out.

[mogga]

I've had an energy saving light melt - or at least the plasticy bit did. About a week afterI'd thrown the wrapper out after having had it a couple of years.

[Andy]

I've had a filament light bulb drop out of its socket before. There was a flash and a thump, and I saw on the landing the baseless glass bulb lying on the carpet. Getting the base out of the pendant socket was interesting. The plastic pendant socket was unharmed though.

When a filament lamp blows, you can get arcing inside as hot tungsten splatters about, and the current can be enough to blow a fuse. If it isn't quite enough, I suspect that if the contact of the base of the bulb to the socket isn't very good, the solder can melt and allow the bulb to drop out.

Andy.

[meow2222]

Fire is always a risk in these cases, though usually not no fire occurs.

MCBs trip when load current gets well above 6A. A bad resistance join does the opposite, reduces load current, so would never trip the MCB. Quite simply there is no protection in most installs against this. Just make sure your kit is sound to start with.

Cue long debate about how much of a problem it is or isnt, about how America does it differently, and about the pros and cons of RCDs and AFCIs.

NT

[Lurch]

On 1 Oct 2005 07:39:41 -0700, [e-mail] scrawled:

Although this doesn't mean it trips at 6.1A.

Not neccesarily, depends what sort of resistance and and what sort of load is going through it.

Basically, shit happens! Stick a new pendant up and be done with it, things break.

[Dave Fawthrop]

| I found my bedroom light bulb had failed yesterday - it's a standard bayonet | fitting below a ceiling rose. However, it wasn't as simple as just changing | the lightbulb - the bulb had fallen out of the fitting. Inspection of the | socket showed that it had largely melted, in fact one of the two metal | spring-loaded electrical connection pins had dropped out, covered with burnt | plastic and melted lead from the bulb contact. The bulb had fallen out | because one of the socket cut-outs, which retain the lugs on the bulb, had | just disintegrated or melted with the heat. | | It sounds like I was lucky not to have a house fire, wasn't I (or not?)? | Why would this happen? Why didn't the relevant MCB on my CU trip (they seem | to do so - irritatingly - every time a bulb in the house blows!) The fitting | was only about 4 years old, is wired perfectly OK, and it's months since | I''ve changed the lightbulb which has worked perfectly ever since. I find | it pretty scary to think what migh have happened, and I haven't a clue why.

Make sure you have smoke detectors fitted and the batteries are still OK.