I bought a replacement bulb for the front porch light, and when I
turned it on, there was a loud POP and the house blacked out. There
was some smoke and sparks as well...(from the light fixture). The
circuit breaker got the lights back on...Did the new bulb somehow do
this? I haven't tried another yet.....or is there a problem in the
light fixture? (the light was working last night...the bulb blew out
I'll second that.
The bulb may have suffered what's known as a "tungsten arc" failure.
That's when the filament breaks and an arc starts between the broken
ends which vaporizes the tungsten filament material into a conductive
plasma. The arc continues melting back the ends of the filaments, with
the current draw increasing as the filament ends get shorter and the
plasma more concentrated until it's occuring between the filament
support wires at which point the current is pretty damn high. It all
takes place in a fraction of a second and it's not unusual for it to
cause a breaker to open or a fuse (in old houses) to blow.
If you've ever switched on a light and had it fail immediately with a
blinding white flash, you've witnessed a tungsten arc.
Years ago quality light bulbs were made with a necked down section in
one of the base lead wires to serve as a fuse which would blow if a
tungsten arc caused excessive current flow. I doubt if any of the junky
bulbs they're selling now have that feature.
If you examine the socket and it's connections and they seem ok, just
try another bulb.
The bulb COULD have lost its seal, became open to air, the
tungsten filament vaporizes at a point and disconnects, falls
down and presents a very low resistance across the interior
wires in the bulb base, makes a flash at the same time it's
tripping the breaker.
Replace the bulb first, try again.
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