"DoN. Nichols" wrote in message
...
On 2013-07-29, Jim Wilkins wrote:

He didn't stay long, the rumor was that he touched a large exposed
electrolytic with 480VAC while putzing with the three phase
connections to a power supply. I was working on a machine next to
it
but out sick that day, and came in to find the floor and the side
of
my machine blackened from the explosion.

Ouch! Good day to be out sick or otherwise out of range.

Touched it with *what*? Something metal to vaporize -- or was
the black from carbonized employee?

The story I heard was that he and another newbie engineer were
attempting to find the proper phase rotation by touching the live 480V
cables to the input terminals while squatting on the floor, and one
lost his balance. I don't remember who said that or may have seen it
happen. Luckily it wasn't me, though I probably would have found a
reason to be on the far side of my machine or taken a break.

Another time a tech was checking a faulty SCR trigger circuit on the
machine beside mine, grounded the scope probe to the SCR cathode and
turned on power. The probe cable exploded in midair before the breaker
could trip. Fortunately I wasn't injured and his weren't serious.

jsw