"jk" wrote in message
...
Jim Stewart wrote:



My shop is wired 415V 3 phase. Did it all myself with an inspection by
the electrical contractor before the sub board was 'hot'. Can't see
it'll kill you any deader than lower voltages. I did it all to code
because *I* was the one going to be using it.

First of all, I'm no expert and I'll certainly
defer to the pro electricians in the group.

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.



A screwdriver dropped onto
busbars can evolve into something that will burn
your arm off or worse.

So can 25V if you work it right, but 440/480 is no worse that 240 for
sustaining a phase to phase arc.

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




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

Proly 4x as great.
------------------
Mr. P.V.'d,
formerly Droll Troll





PDW

jk