Defective Bulb Tripping Ckt Breaker: How Possible ?

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Hi,

Boy, this is a funny one.

Wife turned on a hall light switch last night, big flash by one of the hall
lights, and the ckt breaker tripped.

Was about 2 days since putting in a new bulb there.
Was the el-cheapo brand picked up at CVS, and made in China.

Replaced the bulb with a GE one, and so far everything seems O.K.

Question: I can't imagine how anything, like e.g., a broken filament
perhaps, can short out the circuit.
But, perhaps ?

Can anyone think of a bulb failure mechanism that might trip the breaker ?

Or, might this be just a coincidence ?

Thanks,
Bob

How old is the electrical system in the house? In most places of the
U.S. AFCIs have been the standard since 2002. They were available for
several years before 2002 and may actually be what is installed in your
house's breaker box.

AFCI arc fault circuit interupt type of circuit breaker. Detects the
arc condition and trips.

As others have already stated, the arc in the bulb could draw enough
current to trip most circuit breakers. Is fairly common in my
experience as at least once every couple of years I have bulb "blow"
and trip the breaker. Usually though it is one of the three way bulbs.

 

[Jim Land]

Hi,

Boy, this is a funny one.

Wife turned on a hall light switch last night, big flash by one of the
hall lights, and the ckt breaker tripped.

Was about 2 days since putting in a new bulb there.
Was the el-cheapo brand picked up at CVS, and made in China.

Can anyone think of a bulb failure mechanism that might trip the
breaker ?

How about if you break open the dead bulb, and tell us what what you see
inside? A careful description will provide the clues to diagnose the
problem.

 

[Eeyore]

How old is the electrical system in the house? In most places of the
U.S. AFCIs have been the standard since 2002. They were available for
several years before 2002 and may actually be what is installed in your
house's breaker box.

AFCI arc fault circuit interupt type of circuit breaker. Detects the
arc condition and trips.

As others have already stated, the arc in the bulb could draw enough
current to trip most circuit breakers. Is fairly common in my
experience as at least once every couple of years I have bulb "blow"
and trip the breaker. Usually though it is one of the three way bulbs.

What's a '3-way bulb' ?

Graham

 

[Stephen Tomchuk]

:




What's a '3-way bulb' ?

Graham

Multiple light wattage settings dependant on the switch setting of the
lamp itself. IIRC contains 2 filaments as in 60W, 100W or 160W total
combined with both switched on. YBMV (your bulb may vary)

Steve

 

[James Sweet]

What's a '3-way bulb' ?

Graham

Very common in North America but apparently not sold elsewhere. It's a
single bulb with dual filaments, the most common being 50W and 100W, so
the bulb is 50-100-150W. The base is a standard edison screw base with
an extra contact ring and the socket has a rotary switch on it with 4
positions. Probably 90% of incandescent lamps come with these sockets,
though very often they get standard bulbs inserted in them. The
expensive 3 way bulbs are not very practical, the low wattage filament
almost always fails long before the high wattage one does, and with
triac dimmers as cheap as they are, I'm not sure why anyone even makes
the sockets anymore.


A lot of old 1920s-30s floor lamps used a mogul base version which is
commonly 100-200-300W, these bulbs are still available but I don't think
anyone makes the sockets.

 

[Homer J Simpson]

What's a '3-way bulb' ?

Sounds perverted doesn''t it? Predates residential lamp dimmers.

They have a screw base with a shell contact and two other concentric
contacts.

3 way light bulbs work like this:

1st click - The smaller filament is turned on alone creating the lower light
level.
2nd click - The larger filament is turned on alone (and the smaller off)
creating the higher light level.
3rd click - Both filaments are turned on creating the highest light level.


3 way light bulbs burn out faster because:
Alternating cooling/heating of the two metal filaments shortens their
lifespan.

 

[Sam Goldwasser]

Sounds perverted doesn''t it? Predates residential lamp dimmers.

They have a screw base with a shell contact and two other concentric
contacts.

3 way light bulbs work like this:

1st click - The smaller filament is turned on alone creating the lower light
level.
2nd click - The larger filament is turned on alone (and the smaller off)
creating the higher light level.
3rd click - Both filaments are turned on creating the highest light level.

3 way light bulbs burn out faster because:
Alternating cooling/heating of the two metal filaments shortens their
lifespan.

Rather doubt this. And, the filament that burns out is usually
the one cycled *less* (the high wattage one). Why? Because it is
run for a longer time over the useful life of the lamp.

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[Homer J Simpson]

Rather doubt this. And, the filament that burns out is usually
the one cycled *less* (the high wattage one). Why? Because it is
run for a longer time over the useful life of the lamp.

In every hotel I have ever been in the 3 way lamps are always burnt out on
one filament. Always.


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[Eeyore]

Multiple light wattage settings dependant on the switch setting of the
lamp itself. IIRC contains 2 filaments as in 60W, 100W or 160W total
combined with both switched on. YBMV (your bulb may vary)

Steve

I see. I've never come across such a thing though.

Graham

 

[James Sweet]

Rather doubt this. And, the filament that burns out is usually
the one cycled *less* (the high wattage one). Why? Because it is
run for a longer time over the useful life of the lamp.

For me it was always the lower filament, I figured it was because it was
mostly used on either low or high and less often in the middle, in both
cases that puts more hours on the lower wattage one.