soup wrote:
The Natural Philosopher wrote:


I think its for real, but whether the cables are on, and whether you
can do more than make a cursory inspection, if they are , is a moot
point.

I am sure it is real the circuit is not complete (no earth) so NO
current will flow. seem to remember watching a documentary about this
(the "linesman" stayed on the helicopter platform though) it was "just"
an inspection but there seemed to be no fear of touching the wires.
C.F. Birds CAN sit on power lines without getting zapped (or there would
be lots of dead bird bodies under power lines) but the difference in
voltage gives them a slight tingle which they don't like so they tend
not to perch on power lines.

The arc drawn looks clearly DC...sort of what might be left on a 132KV
line if the contactors flipped out.

Isn't the arc caused by current flow from the helicopter ? Helicopters
can work up a fearsome static PD hence the guys that attach loads to
military helicopters touch the load strop with a grounded pole first.
In a SAR situation allow the winchman to touch the ground/sea first do
not try to grab him (he will probably have some sort of "earthing wire"
running through his harness). If your life depends on it grab the strop
or WHY and take the belt, it is non lethal it just can be very painful
A thread that talks about helicopter static build up:-

http://preview.tinyurl.com/32u6gq

Yes, but those cables are NOT running at full AC.

Its static off disconnected cables and the chopper you are seeing.

AFAIAW teh sequenc to service cable is

- blow the contactors. These are ****ING great switches in tanks of
inert oil designed to quench sparks.

- open up the isolators - drawing a bit of an arc as you do, depending
on leakages.

- go to section of line and throw an earth strap over it to get rid of
static and KEEP it that way. Once isolated it can pick up a lot of static.

- THEN put a man on it.