bz wrote in message
98.139...
"N_Cook" wrote in
:

Arfa Daily wrote in message
...
Sorry all. O.T. as a repair issue. Just something I read about today
that
I'm not sure I understand.

Anybody come across the term "step potential" or its effect in regard
to a downed live power line in contact with the ground ?

Arfa



Hollywood versions show the severed end of the cable, in intermittant
contact with the ground, snaking about like an unsupported hosepipe
issuing a water jet, - true, I don't know ?

Seen it. I was at a gas station north of LSU one day when linemen were
working to straighten a power pole.
They were tightening a guy wire when the winch slipped.

The pole snapped back to 'relaxed position' (about a 3 degree lean) and
the
impulse traveled down the power lines.

The power lines started swinging to-and-fro. The linemen ran. I didn't
know
why.

The wires touched on a swing and arced. Bzzzzzt. A loud, rough, 60 Hz
note.

The arc cut the wire.
The hot wire dropped onto the pavement and started jumping around,
sparking
and buzzing at each contact.

I am standing about 50 feet away, putting gas in my car.
Cars on the street are slamming on their brakes and dodging the hot wire.

Finally, the circuit breaker tripped, killing the power.

THEN I had time to be scared.

I suspect the jumping is due to the magnetic field caused by the current
flow.
One section of the wire attracts or repels another, nearby section of the
same wire.



--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap


Current inducing reaction to earth's magnetism, Fleming's rule fashion ?
As you mention poles, I assume that was no higher than 5 or 6KV

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/