In article ,
-MIKE- wrote:
On 3/3/10 3:00 PM, Robatoy wrote:
On Mar 3, 2:55 pm, wrote:
On 3/3/10 12:55 PM, Robatoy wrote:





On Mar 3, 12:39 pm, wrote:
I thought mythbusters totally disproved it?

That was one that they proved. If you have a solid stream of liquid to act
as a conductor, electricity can follow it. They had quite a bit of trouble
getting a solid stream, but suceeded in the end.

Puckdropper

Really? We're using mythbusters as our final word on science?

Love the show, but they *hardly* hold to scientific method and
occasionally get it right.

In this particular case, if the voltage/current is high enough, you
don't need a "continuous stream." The electricity can arc from drop to
drop to drop.

The voltage would have to be one heckuva lot higher than the 600 volts
typically found on a third rail, which is what Mythbusters was trying
to establish.
For a charge to jump from one drop to the next, to the next the
voltage would have to be a lot higher, such as an electric fence.

Other than that, Mythbusters is a 'reality' show with a twist. They
like blowing **** up to get ratings. One is supposed to suspend any
belief in scientific methods.

Why so serious?

Not serious, just blabbin.

I don't think they ever got anywhere near 600 volts on the show.
I don't know the exact numbers, since I'm only recalling what my buddy
told me (electrical engineer for AEP), but lines that would fall from a
pole near a highway or roadway could be 1000+ volts, and certainly very
high current.

Quite often as high as 23,000 volts. Pee on one of those, and all
that'll be left would be your boots. Dusty boots... likely just
footprints. The 4-part biggies go to 500KV and can carry upward of a
gigawatt.


I was trying to narrow it down do what would be carried by a pole that
could be knocked down in a car accident. But I've seen some pretty tall
aluminum poles near roadways, carrying distribution lines that are
certainly up near the 23k you mentioned.

'typical' residential distribution -- with a 'can' transformer per residence
is going to be in the more-or-less 1.2-4 KV range.

Feeds -to- a sub-station -- one that feeds the residential distribution -- tend
to be in the 15-35kv range.

Metro distribution is usually in the 75-141kv range.

Long haul primaries -- e.g., 'the grid' -- are in the 141kv and up range.
circa 25 years ago, I knew of a _few_ places that were as high as 600+ kv.

The breakdown voltage across an air gap -- what it takes to make a spark
_initially_ jump -- is in the range of 20-75kv/inch. "Clean, _dry_, air
ns at the high end of that range; "damp, dirty, polluted" stuff can be well
below the low end.

Insulation stand-offs tend to be 1" per 'few' KV