Quote:
Originally Posted by ctc17
The CFLs have a fusable resistor that opens when it burns. When the bulb hits end of life the current increases till the switcher burns up, basically their failure mode is smoke.
We had a power surge here several years ago and all the CFLs that were on at the time basically exploded into sparks and flame.
CFLs are bad news, do not leave unattended unless they are contained in a fixture.
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I have a table lamp in which I installed a CFL about five years ago. The lamp still works. I usually leave it on from sundown until midnight or a bit later. The bulb hasn't caught fire yet. I had another CFL in my other table lamp, but it burned out (no smoke) after about five years (!). I know someone who had two CFLs in table lamps in her house; the bulbs simply burned out after several years or otherwise quietly failed.
BTW, I think the design of CFLs must be improved, and quickly, as the deadline for the phaseout of incandescent bulbs in the US is less than a year away. When CFLs are the only type of light bulb available will be no time for people to worry about these lamps setting their homes afire. I can only hope the CFLs made from 2012 forward are designed not to catch fire if they short or otherwise fail. I am surprised CFLs with the fusible resistor even smoke when they go bad -- I would think once the fuse resistor opens, the lamp would go out immediately, period, with no danger of fire, since once the resistor opens the lamp no longer receives power.
The only other thing I can figure is that the fuse resistors in these lamps are placed such that the lamps are still getting power when the fuse goes, which makes absolutely no sense. Also, I wonder why the house fuses do not blow (or circuit breakers do not trip off) when these CFLs fail for any reason. (I have a feeling that the fuse[s] on the kitchen circuits in Electronic M's residence must have been overrated if it or they didn't blow when the short occurred in his GE portable oven; after all, any short bad enough to cause the cord or plug to become red hot and burst into flames is extremely serious -- the fuse should have blown at once.) Again, the only thing that makes sense to me is that the bulbs do not draw enough power, even shorted, to open the breakers, even though a shorted CFL is like any other short in a light socket or anything else plugged into a wall socket; it should blow the fuse immediately, unless, of course, the short is very high resistance -- which I cannot see occurring in CFLs. Once one of these lamps shorts, it is, or at least should be, almost always a dead short across the AC line, which will trip any breaker on that circuit if such breaker is operating properly.