I have 4 6" recessed can-lights in a new bathroom ceiling - all on one dedicated circuit controlled by a dimmer-switch. After they had been installed about a week, I left them on all night very dim, and in the middle of the night one of them exploded - glass all over the floor, base still in the fixture. Assumed I had a faulty light bulb & replaced it. Now, about a week later, the bulb in the same fixture exploded again last night - lights were off this time. Any thoughts? Installation was by licensed electrician.

Although this doesn't really address the rather unusual situation you're describing, you can find some useful lighting information at the following page on the site:

Lighting Basics

this is truely a very strange issue. I have a couple of questions for you.

is there another floor above the ceiling of is it just attic?

when the bulb exploded the second time, had it been off for a while or just been turned off right before it blew?

Just a guess here. Could this one fixture not be sealed thus allowing condensate to drip on the hot bulb? Thats about the only thing that can cause a bulb to explode. Maybe you could try what they call a workshop or hard duty bulb. They are constructed for drop lights and rough duty.I believe they are coated.

JimG

In answer to Va-Builder - there is just unfinished attic above these lights - and they (all 4 lights are on one circuit & switch) had been off for approx 5-6 hours when it exploded.
And in answer to graphix1, that's a good idea to try a heavy-duty bulb, although thee lights are installed in a row down the middle of the bathroom, and this room was so new the shower had never even been used yet, so I don't think there would have been any condensation...

could the wiring of the fixture itself be faulty or have been shorted somehow?

It appears that there is an insulation issue with the fixture-either the sealing of the fixture is faulty or the insulation which isolates the fixture from the attic space has a leak at the fixture-MOST LIKELY. When the light heats up from use-there is an attraction of humidity from the cooler space (much like a glass of cool water on a table on a hot day)-as the fixture cools it builds pressure within the bulb-increasing the chance of explosion. I would suggest sealing the fixture from the attic side as a place to start and the least expensive (most effective as well) If that doesn't work-I would replace the fixture with a 'sealed' unit which is rated for high temp differences.

Hi
I have had similar episodes. The other day one of the bulbs in a track lighting exploded. Glass went flying all over the kitchen floor, the countertops, into and onto food. I am still finding tiny shards in my dining room carpets.
My bedroom is above this fixture and the fixture is attached to a hand-hewn beam. The screw on part of the bulb is still attached inside the fixture and we cannot get it out. We've tried unscrewing it with needle-nose pliers. I have had other bulbs burn out and become fried in the fixtures. I have had to throw away two track light fixtures because even a licensed electrician could not get the remnants of the bulbs out. Is it the bulbs, probably made in China, or the fixtures, also probably made outside the USA. I am beginning to wonder if it is possible to purchase anything of quality anymore.
Carol, New York State < and disgusted.

I also recently had a Phillips 3 way bulb explode right after removing from package and installing in a table lamp. Do not know where bulb made---but probably China. Phillips was VERY SURPRIZED but sent me $10 and form letter. I am more convinced it is the poor quality of the glass.

A. Lewis- Could it be wind blown moisture leaking through a roof vent or furnace flue in attic dripping directly on light fixture below?

If it's new work, there probably isn't BX cable involved, but I had a client once who called and said that his kitchen ceiling fixture was filling up with water. I went, and sure enough, it had about an inch and a half of water in the globe.

I asked him what was above that part of the kitchen, and he said only a low attic and a roof. AHA! I said...it's a humid but cool day, and it's an older house, have someone check to see if there's BX cable in the attic. Sure enough...water was condensing on the metal BX cable sheathing and running along the cable and draining into the fixture.

But his bulbs didn't explode.

Try using compact fluorescent "bulbs" instead of incandescent bulbs. More economical by far, less surface heat. Do that before you seal a fixrure that may need to be ventilated, or go changing fixtures.

Thanks everyone for the suggestions and ideas. I'm going to just try again with another brand of lightbulb. It just seemed really odd that the same bulbs were in all 4 fixtures, everything so far as I can tell identical, and the bulb in just one of the fixtures exploded twice! There is not more than 3 feet between any of them, so it seems to me that any condition that exists in the open unfinished attic above would be the same for all 4 fixtures. I did actually initially use the compact fluorescent bulbs, but of course a dimemr does not work with them - they are either off or on, so that defeats the purpose of installing them with a dimmer - but they didn't explode!

I have 6 4" recessed fixtures in my kitchen. I use 50W halogen floods in each fixture. I had a similar occurrence (twice on the same fixture). I found that the socket was misaligned, only slightly, creating a small amount of pressure on bottom of the flood. After a series of heating and cooling, the glue failed, dropping the bulb's bottom lense on the granite below.

Thanks, Mercer - now THAT makes sense to me. I actually have been mumbling to myself ever since the electrician finished that his workmanship was less "precise" than I would have expected - some of the boxes aren't quite even with the drywall, but of course you can't tell that with the switch or outlet covers on. AND the sockets in the can lights were not QUITE in the center of the fixture. I bet THAT is the problem! Thanks!

I'm not an electrician, but I'm suggesting you may have a faulty dimmer switch. Unlike dimmers of old which were a simple mechanical variable resistor, today's dimmers are energy efficient, solid state devices.

These dimmer circuits have Capacitors that store energy, and a Triac device that acts as a voltage driven switch. With 60-cycle AC power these devices are actually triggering 120 times a second. If the dimmer circuit is faulty, I'm guessing there might be a voltage spike resulting in a sudden rush of current to the filament causing the bulb to explode.

Also, these solid state devices when faulty have been reported to cause high frequence vibrations in filaments resulting in bulbs exploding.

I would, also, guess it may be the last bulb in the parallel connections of the lights, or the last one "on the string," so to speak. That may be your #4.

Obviously, there's one way to find out. If you are the least bit mechanically minded, and you have some standard hand tools, you can inexpensively replace the dimmer. You don't need an EE degree, or a licensed electrician to do that. Just go to the "You can do it...We can help" place.

Don't forget to turn off the circuit breaker and tape it in the OFF position, first!

Here's a great website article on dimmers:

http://home.howstuffworks.com/dimmer-switch2.htm

Hope this helps and good luck.

The post from Mercer is probley the closest to your problem. You will most likley find that the socket in the problem fixture is slightley longer that than the rest. As you screw in the light bulb, the glass makes contact with the socket neck and gets scratched. As you use the light the heat cool cycle causes the scratch to travel (like a stone chip on a car windshield). At some point the scratch becomes a crack and the glass pops off.
Tempory fix, turn off the power and bend the positive contact in the socket so that it makes electrical contact before the bulb glass makes contact with the socket neck. That is a temp. fix because the light bulb is not tight in the socket. True fix is to replace the socket in your fixture. Most all recess lighting Mfg's have replaceable sockets.
I am involved in a lighting business in Michigan and have seen this more than the Mfg's would like to admit.

I'm not as familiar with can lights, but do know that if you don't have the correct bulb, they will explode. I have a small chandelier over my kitchen table. We did not pay attention to the bulbs we purchased and they started falling out....one by one. We did make the connection that you need bulbs made specifically to hang down, and we haven't had any problems since. I didn't know if the can lights were like this or not.

I have known this to happen because the ceiling insulation was installed too close to the can light fixture. This causes overheating and sometimes, depending on its location condensation in the light fixture.The instructions recommend not having the insulation closer than (I'm thinking) 6" to the light and in some cases 1'. See your installing instructions.

Poster "A.Lewis" stated in his second post that the exploding light had been off for 4 to 5 hours when it exploded. That would rule out all the posts following his second post, that spoke to condensation, circuitry and insulation as the culprit, would it not?

The scratch that turns into a break has merit, and I have filed that tip away for future use. But in this situation, the bulb and fixture should cool to room temperature in five to ten minutes after being turned off. If the explosion did happen in the 4th or 5th hour after being turned off, it is hard to make that link.

One question that I don't recall being asked was, "What kind of a bulb are you using?" Certain bulb types generate much more heat than others, but even then, they cool rather quickly.

Assuming you are using quality light bulbs, it seems to point toward some sort of hidden power problem either with the dimmer switch, the internal fixture wiring or the circuity connecting the two. Or else,... it could be a spook!

RB

quote:

Originally posted by angelwynd7:
Hi
I have had similar episodes. The other day one of the bulbs in a track lighting exploded. Glass went flying all over the kitchen floor, the countertops, into and onto food. I am still finding tiny shards in my dining room carpets.
My bedroom is above this fixture and the fixture is attached to a hand-hewn beam. The screw on part of the bulb is still attached inside the fixture and we cannot get it out. We've tried unscrewing it with needle-nose pliers. I have had other bulbs burn out and become fried in the fixtures. I have had to throw away two track light fixtures because even a licensed electrician could not get the remnants of the bulbs out. Is it the bulbs, probably made in China, or the fixtures, also probably made outside the USA. I am beginning to wonder if it is possible to purchase anything of quality anymore.
Carol, New York State < and disgusted.

If you can't get the screw part of the bulb out cut the end off of a potato and push the potato onto the broken lightbulb. Then screw it off...it works, I just did it.