Eco Lightbulb Fear

[Griffin NoName]

Perhaps this should be in "Easy Questions" 

I've been gradually changing over to Eco lightbulbs.

But when ordinary light bulbs expire in my light fittings some of them explode and blow the main fuse.

Eco lightbulbs always carry a warning not to dispose of in household waste - danger!

So if I were to put an Eco bulb in one of the fittings that cause explosions, and I were showered with broken bulb parts as sometimes happens, what is the level of risk to my well-being?

[Sibling Zono (anon1mat0)]

Higher risk by the glass than by the mercury content (unless you lick it ). CFCs should be disposed in designated places because of that mercury content (which is minimal in each bulb but would leak into water reservoirs if disposed in a regular dump).

I somehow doubt the CFC bulbs themselves would explode, with the electronics being fried before such thing (or are you playing with high currents and voltages?).

[Griffin NoName]

No, only playing with normal current/voltage. Never used to suffer exploding light bulbs until my last two homes. Maybe something to do with having had modern fuse boxes fitted replacing the good old sort of yesteryear.

[Swatopluk]

I do not understand how a lightbulb could explode due to electrical malfunction. I would expect just the filament to melt causing no more damage than blackening the inner side of the glass.

A proper CFL contains between 1 and 5* mg of mercury (although some cheap 3rd world imports possibly contain up to 15 mg)
Most of  it (about 80-90%) will firmly bind to the glass but the rest will be released to the surroundings. Unless you break them on a regular base in significant numbers, the mercury should not have much effect on your health. A broken mercury thermometer or barometer would be far worse because the (far larger amount of) mercury will remain and evaporate over time leading to constant exposure. The main danger of metallic mercury is the vapor, the liquid is relatively harmless even ingested (you stomach acid is not strong enough to dissolve it, so it will leave the normal way). It gets really nasty once microorganisms lay their pseudopods on it, for they turn it into methyl mercury that can penetrate your body in any place (including the skin) and is extremly toxic.
According to the EPA all CFLs sold in the US in one year (about 200 million in 2007) would, if not properly dealt with, emit about 113 kg of mercury over time, i.e. about the amount a single Chlor-Alkali plant using the mercury cell process emits per year. Coal fired power plants are worse and the demercurisation of the stack exhausts is at best imperfect and quite expensive (so, esp. US plants try to avoid doing anything about it). Your highest personal exposure to mercury will likely be from freshwater fish (dental fillings following far behind).
Back to the lightbulbs, the (technically illegal) conditions in Chinese production facilities and the reopening of mercury mines are in my view the greatest danger. Mercury travels fast, it usually does not stay where it is emitted and distributes all over the Earth in as little as a year (for emissions to air, by water probably a bit more slowly).

So, don't feed the lamp shards to colonies of mould, don't dissolve them in strong acid and do not eat more than one lamp per week  Infections through cuts by sharp shards shoudl be your main concern. Depending on the lamp (not just the bulb) you may consider a fine metal mesh or a (heat resistant!) translucent plastic bulb cover**. High class bulbs should actually be already covered with a thin layer of plastic to avoid flying shards.

Just for those interested in why I do have all that info at hand, it's a topic currently discussed at my workplace. I'll have to do a paper about it when I return from my holidays (staying at home).

*legal limit
**but be careful that you don't create a heat trap that way.

[Bob in a quantum-state-of-faith]

Thanks, Swato.

You've covered what I was going to write, so I'll just have to go off on a tangent...

I can only add this:  the white powdery lining of CF's contains (among other things) phosphorous.  As a powder, it's not very dangerous, unless you get it into an open wound-- then shades of WW2 "willy-pete" grenades.  (But only a shade/shadow of that awful weapon...)

The best disposal of broken CF glass is with a broom and a dustpan.  Avoid motorized cleaning tools, as the dust is fine enough to blow right through most filter bags.  Dump into a sturdy paper sack, box or other container, then wrap the whole in a plastic bag and tie tight.   Once the majority is swept up, a regular vac is okay-- what's left is insignificant enough to not worry about.

I've been using these things since the early 90's (when they were expensive and hard to find-- but made quite robustly-- I'm still using one from that era-- it still works).   As result, I've busted quite a few in the intervening years.

The typical "bust" is the glass envelop cracks, and lets air in to spoil it-- it won't light-off with air inside.*    But, I've literally shattered the whole thing with my fingers before-- no cuts, thank goodness.  The glass is usually quite thin-- fragile even.   And, it lacks the advantage of being spherical a regular bulb has.   If you're worried, leather gloves is easily strong enough to protect from glass shards.

Alas, the most common failure is the modern electronics these things now use-- these circuit boards are typically cheap junk, and the components fry all too easily.   You'll know, because the glass does not have any visible cracks or blemishes.  Yet the thing acts like the power's off... smell it.   You'll usually smell the magic smoke** escaping...

Many larger communities have CF recycling centers, now.  The phosphorous powder, argon and mercury are 100% recyclable.  So is the glass.  The electronic board?  Junk-- destined for landfill.  As is the plastic housing bits.  Many have aluminum shells in the base-- again, 100% recyclable.

____________________

*Warning! Science Content! There's supposed to be a partial vacuum, with a few molecules of mercury vapor as a "starter" charge, and argon gas as the "working plasma" (under low pressure).

What happens is this:  a very high voltage arc-flashes from one end of the tube to the other, utilizing the mercury vapor to reduce the resistance significantly.  Once the current "flashes over" the argon heats up, and goes into a plasma-state.  The electricity passing through this now conductive plasma causes an electron orbital-jump to high state, then back to low.  When these return to low, they emit ultraviolet radiation.

This ultraviolet light is invisible to humans, but that's where the white powder comes in:  the uv strikes the powder, which absorbs it (and causes *it's* electrons to jump to a higher state, then back again).  The return to low state emits radiation all across the visible spectrum.

The glass envelope blocks any leftover UV radiation, which is eventually emitted as heat-- the glass warms up.

The way they get the white powder to emit all across the visible radiation spectrum, is by mixing many different phosphorous compounds together in a "dry mix".  Each individual phosphorous compound emits a narrow-band color.  Change the compound, and you change the narrow-band to a different color.  Enough of these, with enough different colors, and you get white.

Remember the fluorescent lights of the 60's?  Remember how greenish they made everything look?  It was because the chemistry of these phosphorous compounds were still in their infancy, and they lacked the color red, mostly.

They've fixed that, these days...

____________________

** Anyone who's ever worked directly with electronics (aka with a soldering iron, etc) knows well the smell of the magic smoke.  This magic smoke is infused into all electronic parts at the factory.  It is what makes them go... if the smoke escapes?  The electronics won't work any longer.

Many things can let the smoke out:  too much voltage is the most common culprit, even a millisecond of too high voltage can let the smoke out.  Another avenue for smoke escape, is too high heat (as with a soldering iron left in contact for too long, or the volume turned up too high, or too much dust clogging the works).

However, the chief difference between cheap electronics and quality electronics is the cases for the cheap ones is thinner, and is more apt to let the smoke out prematurely.

[beagle]

But when ordinary light bulbs expire in my light fittings some of them explode and blow the main fuse.

My guess is they've failed by a vacuum (or rather inert gas) breach, and then heated asymmetrically with the fractured glass shorting the heavier wire supporting the filament.   As pointed out, the newer ones don't have the prerequisites for that.

Don't know why it should be more prevalent recently though, unless all the quality manufacturers have moved to the new type. Or you made them yourself .

[Opsa]

Goodness, you people are informative! Thanks for a fascinating read, professors!

[Griffin NoName]

I do not understand how a lightbulb could explode due to electrical malfunction. I would expect just the filament to melt causing no more damage than blackening the inner side of the glass.

It's when the bulb's life expires, there's a loud pop, all the lights go out (lighting fuse at fuse box blows) and the bulb parts company at the neck - metal bayonet fixing seperates from blackened glass neck. The force is so great that the glass bulb ejects from the light shade entirely and flies across the room. I was told by an electrician it is something to do with the old fuse boxes being 3v and new 5v.

[beagle]

Strange. I thought lighting circuits had been 5A since time immemorial.

Maybe I was wrong. Possibly it's demonic possession. Do you cast a shadow? When the light is still working I mean. Another conceivable explanation is that that your electrician can't tell Amps from Volts.

[Griffin NoName]

I think the volts and amps mistake was me being electrically dyslexic.   I meant amps but was thinking in volts or possibly even UV. Or something. On the other hand, a 3V fuse box would be kind of interesting.

I've checked my shadow. It's there, but back to front. Could be the problem.

Trying to work out a google phrase for "has it been 5A for ever?". Maybe a ? for WolframAlpha.

[Bob in a quantum-state-of-faith]

I do not understand how a lightbulb could explode due to electrical malfunction. I would expect just the filament to melt causing no more damage than blackening the inner side of the glass.

It's when the bulb's life expires, there's a loud pop, all the lights go out (lighting fuse at fuse box blows) and the bulb parts company at the neck - metal bayonet fixing seperates from blackened glass neck. The force is so great that the glass bulb ejects from the light shade entirely and flies across the room. I was told by an electrician it is something to do with the old fuse boxes being 3v and new 5v.

Correct me if I'm wrong, but does not the UK use 230v A/C for all it's mains?  We yanks are used to 120v (nominal), which is (supposedly) safer.  But 230v lets you do the same work with smaller wires. But your insulation must be proportionately better.

As for 3A vs 5A?  The 2A difference is all but trivial, in my experience-- most modern fuses should be able to withstand a spike in amps of 2 or 3 times the rating, that is, a 3A fuse *ought* to be able to pass a spike of 10amps or more, for an instant.

The blowing of your bulbs ought to be within these parameters.  Makes me wonder about the insulation integrity of your light sockets, instead.   If the lamp itself is compromised, whenever the bulb fails, it causes a chain reaction, creating a direct short to ground condition.  Which **would** blow the bulb apart, and the fuse too.  Thats actually what the fuse is for:  to blow in the event of a direct short-to-ground.

Hmmm.

I'd investigate that lamp/light socket-- or have it done, soonest.

Such behavior is **not** normal, and **could** create a spark-condition that starts unwanted combustion...

...seriously. 

Now, I'm gonna have to worry.... 

[beagle]

I had a hunt around. Apparently the tungsten filament can develop weak spots which then get weaker still as a local hot spot. When the filament breaks it can arc, resulting in a burst of high current and temperature which can shatter the bulb.  Good quality bulbs are supposed to have an internal fuse which fails before the domestic fuse or circuit breaker.

Yes, UK  uses 240V at around 13A maximum per socket.  don't know if it's true but I've heard electric kettles are less common in the U.S. because they are slower without 3KW elements.

[Bob in a quantum-state-of-faith]

I had a hunt around. Apparently the tungsten filament can develop weak spots which then get weaker still as a local hot spot. When the filament breaks it can arc, resulting in a burst of high current and temperature which can shatter the bulb.  Good quality bulbs are supposed to have an internal fuse which fails before the domestic fuse or circuit breaker.

Yes, UK  uses 240V at around 13A maximum per socket.  don't know if it's true but I've heard electric kettles are less common in the U.S. because they are slower without 3KW elements.

Well, that may be true with regards to electric kettles.

It could also be due to the predomenence of a couple of things:  Cheap coffee makers that are reasonable tea-brewers too, that most houses have hot water on-tap (and many tea drinkers I've encountered brew tea with just hot tap water-- don't blame me, I drink coffee) and a distinct cultural lack of 'tea time'.   

We have coffee breaks instead: wherein a vile near-black liquid is quaffed in small quantities from paper, plastic or styrofoam cups over a running commentary of who in the office is sleeping with whom... 

Personally?  I blame much of the current economical woes on the lack of tea time in the US.

[beagle]

...many tea drinkers I've encountered brew tea with just hot tap water...

Don't mention this to Swato. He may never recover from the shock.

We have coffee breaks instead: wherein a vile near-black liquid is quaffed in small quantities from paper, plastic or styrofoam cups over a running commentary of who in the office is sleeping with whom... 

Our canteen coffee is generated from beans while you wait, but at a cost of about US$2 a cup, so I drink kitchen made tea most of the time. Even Fortnum and Mason's tea is a fifth the price of the coffee.  For your $2 though you can find out more about the state of local business by chatting with the staff than any number of government statistics would tell you. And with more laughs. No information in the who's-had-who department though. Possibly you have to buy a cake as well to get that.

[Griffin NoName]

I'd investigate that lamp/light socket-- or have it done, soonest.

Such behavior is **not** normal, and **could** create a spark-condition that starts unwanted combustion...

I had a hunt around. Apparently the tungsten filament can develop weak spots which then get weaker still as a local hot spot. When the filament breaks it can arc, resulting in a burst of high current and temperature which can shatter the bulb.  Good quality bulbs are supposed to have an internal fuse which fails before the domestic fuse or circuit breaker.

My electrician knows the bulbs blow and doesn't seem to think its a problem. It seems more likely what Beagle says as I buy supermarket bulbs which are cheap.

Yes, UK  uses 240V at around 13A maximum per socket.  don't know if it's true but I've heard electric kettles are less common in the U.S. because they are slower without 3KW elements.

And we use three square pin plugs ........ I just got a USB hub adaptor off Amazon from a company in Guernsey and the plug fitted was two round pin continental. The postage to return it would be more than it cost. I feel ripped off*. Think twice before buying from the Channels Islands if you are in the UK!

*yeh I could use an adaptor but that's not the point