[Avodah] electricity on shabbat

[Micha Berger]

On Wed, Jan 06, 2010 at 08:42:01AM +0200, Eli Turkel wrote:
: To be a psik reisha sparking would have to occur every time
: one used the appliance not just over the long run. I severely
: doubt that most appliance are constantly sparking.
: Also as the article points out modern electrical appliances are
: arcless.

I suggest takig the casing off a light switch and seeing ho often there
is a spark right before it closes. I would guess it's above 90%.

Similarly, a motor running on outlet-sized voltage, assuming it has
brushes and isn't running at 50 rpm (60 rpm if you were in the US),
say the one in your blender. If you took off the casing and saw where
the brushes touch the plates. I bet there is a spark nearly every time
the brush goes from one plate to the next, multiple times a minute.

Unlike in a spark plugs, these are lo nikha lei.

: This issue came up again with using (special shabbat)elevators on shabbat.
: RSZA said it was not a problem because it is unintentional,
: too small to be seen or have heat as is not psik reisha....

I don't see the problem for a different reason. My weight's *contribution*
to causing those sparks has negligable effect on the sparks, the lights in
the various indicators, etc... I think that was the essense of what RYZ
of Zomet was speaking of. But here we're talking about being the person
who flips the switch, e.g. the use of a regular elevator. "Everyone"
holds it's assur, although reasons why differ, and the opening question
was how to explain to someone still exploring Yahadus the CI's reason
why. This rapidly shifted, as replyers noted that the CI's reason isn't
the more easily understood, nor the most often cited.

Tir'u baTov!
-Micha

-- 
Micha Berger             "Fortunate indeed, is the man who takes
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