"Proctologically Violated©®" wrote:


"jk" wrote in message
.. .
Jim Stewart wrote:
That said, 440/480 is uniquely dangerous in it's
ability to sustain a plasma fire without tripping
upstream breakers.

Not so at all

I think the previous statement is likely correct. Given adequate current
supply, voltage determines arcing ability.
I don't know if 440 is the magic number, but certainly the higher the
voltage, the more likely this ability becomes.

The generally considered (such that there is one) "Magic number" is
100 V to sustain an arc in air.

400 some odd volts is in no way "uniquely dangerous". Yes it is more
dangerous than 200 some odd, and less so than 600 some odd or 4160.



440 is worse for everything safety-wise. P=I^R=E^2/R, so the power capacity
of higher voltage is quite significantly higher.

Only if you ASSUME that the available fault current is the same, which
in general it is not.

But higher voltage also lowers power losses in wire, increasing motor
efficiency. Which is why it's used in heavy duty applications.
I've seen 208 in a shorted 3 ph plug sear the skin off a whole palm of a
hand; imagine 440!

That is based solely on arc currents, distance and exposure time, and
the chances are better (if not good) that you have a current limiting
device upstream at 440.

I think the electrocution risk is substantially
greater than 240V as well.

Proly 4x as great.
------------------

Probably and provably not. Far and away the greatest number of
electrocutions occurs from 120 V circuits in the US. Yes the higher
voltage can punch through the skin barrier easier, but far more people
treat 120 in a very cavalier fashion.
jk