wrote:
On Sat, 24 Mar 2018 17:51:26 -0400,
wrote:

On Sat, 24 Mar 2018 14:52:35 -0400, "Mr. Luddite"
wrote:

On 3/24/2018 2:28 PM, wrote:
On Sat, 24 Mar 2018 13:30:10 -0400, "Mr. Luddite"
wrote:



but not for me ...

https://tinyurl.com/yb9cbkae


===

That's an impressive looking arc. I wonder how many volts were on
that cable?


I think the standard voltages for distribution is now 69,000v and
115,000v in most places.

Some lower ones are 13,500 volts but would not draw an arc like that.
The house we had in Duxbury was fed underground from the road to a
transformer closer to the house. It was 13,500v in a coaxial cable to
the primary of the transformer. The secondary fed two, 200 amp panels in
the house and another 100 amp panel in the garage. It shorted one day
where it ran into the ground by the road and the whole ground shook.
It's amazing though. The primary fuse on the pole is only a 15 amp fuse.

Lotsa volts anyway.


===

Lotsa volts for sure. I sort of recall a rule of thumb that
electricity can jump a 1/4 inch air gap for every 1,000 volts. I'd
estimate the arc in the video at about 3 feet, which leads to a quick
voltage estimate of 36 x 4 = 144KV. It might have been lower however
because once an arc is struck it can extend farther because an
ionization path already exists. That's the principle behind a "Jacobs
Ladder" which is kind of a cool demonstration.

https://www.youtube.com/watch?v=6hhaaSSCU5k



My neighbor does this kind of thing for a living (FPL). He says, with
the right training and the right tools, this isn't scary at all. You
notice that guy is nowhere near the arc and he does everything with a
hot stick from a well insulated bucket.
Just a wild guess looking at the insulators and the mounting my guess
is this is medium voltage distribution 13.5/23.3 wye. It could be 69kv
but that is usually on a more substantial mounting with arms off the
poles.
Like you say, once you strike that arc, it can go a while. We had
quite the light show when Charley took out the 13kv line in front of
the house.


The main distribution lines through the center of California are 500KV.
Family friend worked for PG&E when a crop duster hit the line. Engineers
figured would take down 4 towers if plane crash. Took out 7. He said a
special crew works on the line. They are in Faraday suits and they shut
down the broke line and reduce the power in the parallel line and ground
the broke line a mile each side of the break. Then at each tower closest
to the break another ground line. He said the closest grounds lines to
the break carried 200 amps. That is induced in less than a mile of wire.
He figured they were nuts. Plane and pilot were crisped.