Re: Insteon Observations

[Victor Roberts <xxx@xxxxxxxxxxxxxxxxxxxxx>]

On Fri, 15 Dec 2006 22:36:36 -0600, G. Morgan
<alarmpro@xxxxxxxxxxx> wrote:

>On Fri, 15 Dec 2006 21:24:59 -0700, AZ Woody <reply@here> wrote:
>
>>Dave Houston wrote:
>>> 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.
>
>
>>Come on...  This is all like discussing how many angels can dance on the
>>head of a pin...
>>
>>In reality, don't most folks buy light bulbs at Home Depot, Lowes,
>>Target, Walmart, (or at their local food store if they ran short)!
>>
>>I doubt that 99.9999% of the folks would buy "fused bulbs" vs "unfused
>>bulbs" but will buy what's on sale..  Do you all not have a life?
>
>
>The fundamental question for me is whether or not light bulbs can
>cause equipment damage.  And no, I have no life.

If the branch circuit has appreciable inductance, then when
the current first increases and then abruptly goes to zero
when the internal fuse blows, a small voltage spike could be
generated.  This could damage other equipment on the same
branch circuit, but I have never seen or heard of such
damage.


--
Vic Roberts
http://www.RobertsResearchInc.com
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