Re: Big Powerstats was RE: Unknown Powerstats

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Tesla729-at-cs-dot-com 

In a message dated 8/30/03 10:14:13 PM Pacific Daylight Time, 
tesla-at-pupman-dot-com writes:

>Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
>
>
>Dan &Adam:
>
>I would definitely NOT use your triple stack variac with the hand control
>wheel.  If there is a short circuit or variac flashover, this means a
>tremendous "flash explosion" which would severly burn or kill anyone near
>it.  The fireball predicted at 20 kVA is over 8 feet in dia. and the
>flashburn would be very nasty especially if you are facing the unit.  You
>would probably never see again.


Dr. R, all,

I would tend to disagree with this prediction. Assuming that the
circuits of your home have adequate overcurrent protection, the
circuit breaker/ fusing should prevent the time duration of direct
short circuit currents to the millisecond level. I have personally
inadvertantly shorted 240 volts on a 60 amp breaker circuit and
although it did make quite a POP and caused some carbonized
stains on the nearby wood surface, it did not come anything near
an "8 ft. fireball". The only time that I have witnessed a "fireball"
that spectacular is with a phase to phase short on 13.2 kV mains
primary lines, which I'm sure represents considerably more than
20 kVA (probably < 20,000 kVA).

Don't get me wrong. I am certainly not trying to down play the dan-
gers of electricity. I just don't think 20 kVA shorted would cause
that much energy flash unless it was not overcurrent protected at
all, like straight off the pole. And I'm assuming everyone here is
smart enough not to try something like that :^)

BTW as a firefighter, I have witnessed flashburns on a maintenance
electrician at school building, that accidently shorted the 480V, 3-
phase mains buss in the breaker panel box for the entire school building
(probably straight off the pole before the circuit breakers).He
sustained some nasty second and third degree burns on his head
and face. He was still consious and coherent but obviously badly
shaken up and probably partially in shock, although he didn't seem
to be blinded. I'm sure his healing was long and painful and most like-
ly left some permanent scars. Also, severe burn locations are in dan-
ger of developing potentially life-threatening infections until completely
healed up. Be careful!!

David Rieben