Re: Insteon Observations

[nobody@xxxxxxxxxxxx (Dave Houston)]

G. Morgan <alarmpro@xxxxxxxxxxx> wrote:

>Anyway,  I have never experienced what you describe (a circuit breaker
>trip) on failure of a bulb.  My common sense tells me the arc (air gap
>resistor) would be a great, sudden, resistance that would indeed draw
>a large current spike.  Part of me thinks the opposite is true - for
>which I have no basis!
>
>I was not aware that common bulbs had a fuse either, I thought the
>filament IS the fuse.
>
>My interest in this has nothing to do with Insteon devices, it has
>more to do with what I can do to protect the circuit for devices I
>install, if the theory is true.  It may explain some anomalies I've
>experienced with security devices.

The tungsten-arc is for real. The built-in fuse is also. If you hear a "pop"
and see a bright flash, you're buying cheap bulbs. If you hear a "poof" and
notice a bit of a flicker before darkness descends, your bulbs are fused
(even if cheap).

The inrush current for an incandescent is about 10 times the current once
the filament has warmed to its normal temperature. For a 100W bulb this
means an inrush at turn-on of +8A. The "fuse", if any, built in to the wire
leading from base to the filament should withstand the inrush but blow
before a 15A breaker is tripped by a tungsten-arc.


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