Fire!

[old_coot88]

Originally Posted by Electronic M

I grabed the cord and yanked it out of the outlet! It was a miracle the plug came with as one of the wires was completely evaporated from the plug to about 1/4" away, and the cord end of the melted lead had the conductor exposed. The strands at the exposed end had melted together and fused for about 2mm!

Of course the kitchen fuse never blew.

Did you check the fuse box to see if someone mighta put over rated fuses in? Or coins to bypass the fuses? That's been done more times than one might think.

[Electronic M]

most of the fuses were newer (I tended to do stuff that would blow them when I was younger than that. No coins, slugs, or tokens were ever used to replace a fuse by my folks, and none were ever found to my knowledge.

I was told a story by my folks that when they first moved in the lights were dim, and would flicker, and after a tornado which took out a large tree in the back yard which in turn took down the over head utility wires, a utility worker came in to inspect the fuse box, and discovered that the main cartridge fuses had been replaced by the previous owners with UNDER rated replacements that were limiting the power supplied to the place.

[jr_tech]

I have used CFLs for over 10 years and have not seen a failure that involved more than a small amount of burned resistor smell in the room. By last count, I have about 30 of these devices in my house.

For grins, today I cut open 3 failed units (I save them for recycle because of the tiny amount of mercury in each tube).

In the oldest unit (which had been in service since 4/28/01), a small fuse (marked 4A) was the first component in the circuit before a cap and the diode bridge. In two newer units, a small 1/4 watt 4.7 ohm resistor and a coil wound with very small wire preceded the cap and diode bridge. In one unit, the resistor was open, in the other (which was replaced because it had started to flicker somewhat, when cold) the "fuse" resistor was ok. Nothing that I found in the units that I autopsied gave me any cause for concern.

I also did a "flame test" (using a match) on small piece of plastic from one of the bases and found that it only melted, and did not appear to support combustion after the match was removed.

Perhaps some earlier units or obscure brands were not fused, I don't know! Mine were marked "GE" , "N:Vision" and "Commercial Electric".

jr

[jr_tech]

Just found a Sylvania and took it apart... it had a 3 Amp glass fuse covered with shrink fit between the board and the center contact of the screw-in socket. I like this design, as it possibly could provide somewhat better protection in the case of a over-voltage line spike, which might create a charred path if the fuse or fuse resistor were mounted on the circuit board.
jr

[cbenham]

Originally Posted by Chad Hauris

I have noticed for old equipment that was designed for commercial/industrial use (jukeboxes, PA amps, broadcast equipment) and which was designed for 24 hr. a day use there is always fuse protection in the power line and usually additional protection such as a B+ fuse.

During the 6PM News I ran camera at an ABC TV affiliate in Florida. I saw an orange flicker down to my left which turned out to be the flyback in an RCA B&W Studio Picture Monitor burning brightly.

I dragged the beast by the power cord out of the studio and hit it with the fire extinguisher. The important point I made in my report was that the monitor had a 0.25 amp fuse in the B+ line to the flyback and a 2.5 primary line fuse. Both were the right value and NEITHER FUSE BLEW during the excitement.

So much for fuse safety.

Cliff

[David Roper]

Originally Posted by Electronic M

the main cartridge fuses had been replaced by the previous owners with UNDER rated replacements that were limiting the power supplied to the place.

Fuses "limit the power supplied" in one way and one way only: they blow. A fuse is an all or nothing proposition. Something else must have caused the flickering.

[Reece]

A fuse is an all or nothing proposition. Something else must have caused the flickering. Agree. In an old house, there are lots of mechanical splices that oxidize and cause intermittent circuits. In one old house I lived in, one day a table lamp slowly went out, then flickered low. I went in the basement and traced the knob-and-tube wiring from that outlet to a friction-taped splice where I could see a blue glow through the loose tape! That got taken apart and soldered.

[wa2ise]

Originally Posted by old_coot88

Or coins to bypass the fuses? That's been done more times than one might think.

Reminds me of the dorm I lived in back at Syracuse U. No, no fuse panels, they used circuit breakers. But they had in the stairways wall fixtures that held light bulbs upwards. And the students would often steal the bulbs to replace burnt out ones in their dorm rooms, leaving empty sockets. Then some rocket scientists thought it'd be fun to drop a penny into the live but empty light bulb sockets to make some sparks. ZZZAAPPPPPP!. THe college eventually replaced the fixtures with vandal proof enclosed plastic fixtures.

[kx250rider]

Originally Posted by jr_tech

I have used CFLs for over 10 years and have not seen a failure that involved more than a small amount of burned resistor smell in the room. By last count, I have about 30 of these devices in my house.

For grins, today I cut open 3 failed units (I save them for recycle because of the tiny amount of mercury in each tube).

In the oldest unit (which had been in service since 4/28/01), a small fuse (marked 4A) was the first component in the circuit before a cap and the diode bridge. In two newer units, a small 1/4 watt 4.7 ohm resistor and a coil wound with very small wire preceded the cap and diode bridge. In one unit, the resistor was open, in the other (which was replaced because it had started to flicker somewhat, when cold) the "fuse" resistor was ok. Nothing that I found in the units that I autopsied gave me any cause for concern.

I also did a "flame test" (using a match) on small piece of plastic from one of the bases and found that it only melted, and did not appear to support combustion after the match was removed.

Perhaps some earlier units or obscure brands were not fused, I don't know! Mine were marked "GE" , "N:Vision" and "Commercial Electric".

jr

I wish I had the same experience, and I'm glad yours haven't acted this way, but PLEASE be mindful that this can happen. These pics are of the one which falied in our barn, and had it not been for the fact that the barn is built of asbestos siding and a steel roof on a concrete floor, we'd have lost it, and since this happened during a Santa Ana Wind, it likely would have taken out other buildings and a few hundred acres of wildlands. The County of Ventura, CA fire marshal put out a public warning about CFL bulbs, and stated that they should never be used in lamps with paper or cloth shades, and never in recessed ceiling "can" lights.

Charles

[AUdubon5425]

The only place I have these is in the lamps outside the front door - the kids inevitably slam the door and CFLs don't have weak filaments to break. After reading this thread, I think I'll use rough-service shop light bulbs when replacement time comes, and paint them amber myself.

[jr_tech]

Originally Posted by kx250rider

I wish I had the same experience, and I'm glad yours haven't acted this way, but PLEASE be mindful that this can happen. These pics are of the one which falied in our barn, and had it not been for the fact that the barn is built of asbestos siding and a steel roof on a concrete floor, we'd have lost it, and since this happened during a Santa Ana Wind, it likely would have taken out other buildings and a few hundred acres of wildlands. The County of Ventura, CA fire marshal put out a public warning about CFL bulbs, and stated that they should never be used in lamps with paper or cloth shades, and never in recessed ceiling "can" lights.

Charles

Yikes!
Thanks for the heads up! interesting comment about the fire marshal as well. Could you tell from the charred remains if the lamp was indeed fused?
jr

[Electronic M]

I know a fuse is either a short or an open, and what my folks told me did not make sence to me either. It is possible that the fuse was mechanically too small and was making poor contact, or there was another issue the guy corrected and did not tell them about.

Wow that CFL is really toasted.
There is an office in my school that is usually left open that has a desk with a CFL that burned at the points the tube enters the base. I think it is on permanent display as it has sat there for over 1 year now.

[dieseljeep]

Originally Posted by wa2ise

Reminds me of the dorm I lived in back at Syracuse U. No, no fuse panels, they used circuit breakers. But they had in the stairways wall fixtures that held light bulbs upwards. And the students would often steal the bulbs to replace burnt out ones in their dorm rooms, leaving empty sockets. Then some rocket scientists thought it'd be fun to drop a penny into the live but empty light bulb sockets to make some sparks. ZZZAAPPPPPP!. THe college eventually replaced the fixtures with vandal proof enclosed plastic fixtures.

That's no fun! I used to use a small bit of steel wool, stuffed in the sockets. It would produce a shower of sparks when it was energized.

[Phil Nelson]

Guess you shouldn't leave your Sony Brevia playing unattended, either. Sony just recalled 1.6 million of them due to fire risk:

http://www.bloomberg.com/news/2011-1...levisions.html

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[M3-SRT8]

Dave, which 721 went up in smoke? The TS or the TCS?

Lee