Re: O.T. Step Potential ...


"Smitty Two" <prestwhich@xxxxxxxxxxxxx> wrote in message
news:prestwhich-F3080E.09403415042008@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
In article <4aWdnZ63l9OvV5nVnZ2dnUVZ_u6rnZ2d@xxxxxxxxxxxxx>,
"Michael A. Terrell" <mike.terrell@xxxxxxxxxxxxx> wrote:

It all boils down to
Ohm's law, and the current path to every point that is well grounded.
If you have no other choice, you want to take as small of a step as
possible, but a pair of dry shoes add a lot of protection. It's possible
that the ground might only be 10 feet from where the wire touches the
ground. If that is a 7200 volt line, that would be 720 volts/foot. In
that case you would get a shock, even if you are standing on one foot.

I'm envisioning an episode of Man vs. Wild here...

"I'm being dropped down into a veritable electrical minefield, with
hundreds of writhing high tension lines covering the ground for as far
as the eye can see. I'll show you how to thread your way through this
potentially (sorry) lethal maze by using your pocketknife to fashion a
crude voltmeter from an eyeglass hinge, a bootlace grommet, and some
carefully woven root fibers from the native weeds."

Bear Grylls could do it too ! Do you get his TV shows there ? He's an ex
British Special Services survival specialist, and he's a sort of cross
between an escaped mental patient, and Steve Irwin ... Totally mad, but full
of *really* useful and practical nuggets of survival technique. He really is
the sort of bloke that you would want with you, if you found yourself
somewhere really inhospitable ...

Going back to the step potential question, thanks all for your thoughts. You
all seem to understand it pretty much as I (thought I) did. I think that the
concentric circles thing is just an attempt at simplification so that it
makes for an 'interesting' and understandable in principle article in a
company mag for general reading by everyone i.e. office staff, managers,
those in the field and so on. I think we'll settle on there being a
potential gradient between the downed cable's point of contact with the
ground, and the points around it where the land sinks back to inert ground
potential. We'll also take it that this could be largely round, and very
gentle if you were in an open field, and might be far from round and steep
in particular directions towards nearby 'good' grounds in an urban area.
Further, the gradient might be linear, and might not, depending on ground
conductivity in any direction between the point of contact, and inert ground
potential. Sound a reasonable analysis ?

Arfa


.

Relevant Pages

  • Re: Granny Squares? instructions
    ... I can put up with specific directions. ... Okay, here goes, written instructions to crochet a granny square. ... You already know how to get the first round. ... is the first dc of a cluster of dc3, you need to crochet dc2 into ...
    (rec.crafts.textiles.yarn)
  • Re: Seat assignments at tournaments
    ... allowed to sit wherever they like for the first round or they assigned ... If East and West are likely to play ... half the hands each, and East and West change directions every round, ... but what people do is to switch ...
    (rec.games.bridge)
  • Re: pick up in boston
    ... Ebersol Field ... Directions: We play every Saturday, year round, on Boston's scenic and ...
    (rec.sport.disc)
  • Re: continuous boot loop
    ... > the diretions on the norton site to remove it. ... > of the directions i was instructed to edit the registry. ... > gets is the black WINDOWS XP screen that shows windows is ... Round and round and round and round she goes! ...
    (microsoft.public.windowsxp.security_admin)