h a l f b a k e r y
Where life irritates science.
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
or get an account
Certain emergency workers don't have the luxury of getting
out of storms. Proposed is a personal lightning rod consisting
of grounded boot plates, a metal helmet, and wiring in
[marked-for-deletion] Redundant [hippo, Jun 14 2012]
||It amuses me that this posting is currently (no pun
intended) next to [UnaBubba's] posting about artificial 3rd
arms. Perhaps the 2 ideas should be combined.
||There's a matter of resistance to deal with here; most
lightning rods, let alone those light enough to wear, are
not sufficient to conduct _all_ of the tremendous current
that is unloaded by a lightning strike. What they do is
guide it in a relatively harmless manner to the ground.
Because of the resistance built up in the rod and ground
cable, much of the current follows that path by arcing
through the air near the conductor, 'jumping' into and out
of the cable as the current fluctuates, and arcing across to
any nearby conductors that off less resistance--and, with a
30,000-amp arc delivering a terawatt of juice at 140,000
mph in 1/30,000,000 of a second, nearly anything is a
conductor--bringing the lightning safely to ground without
||A human body is a very good conductor. A human wearing
a lightning rod will be a very convenient secondary path
for that arc. Food for thought.
||//with a 30,000-amp arc delivering a terawatt of
||Actually, a lightning bolt contains 1.21 jiggawatts of
||My mistake. Somewhere, I read 'up to' a terawatt,
obviously an erronious figure. It's still a helluva jolt, any
way you slice it.
||I didn't bother to cite a reference for the above
description of a lightning rod's function because I've
personally witnessed it multiple times while working for
the railroad. Railyards understandably attract a lot of
strikes, so most of the buildings have fairly beefy lightning
rods. Standard car shop protocol during a lightning storm
was for everyone to stop work and gather in an open area
of the shop as far as possible from any metal, so we would
often open up the big doors and watch the rods on the
buildings opposite. When we were 'lucky' enough to witness
a strike, the after-images seared into our retinas clearly
showed that the arc had twisted and forked on its way
down the ground-wire, leaping out to touch the sides of
the building, nearby materials or equipment, or the tarmac
around the ground anchor.
||Having seen something like that is proof enough for me.
Anyone who doubts my veracity is welcome to *conduct*
their own research.
||Most people who get "struck by lightning" are shocked indirectly via the ground or a nearby object. Having a metal pole above you might be worse becasue it would attract more lighning. Also you would need some killer insulation on the wiring going from the rod to your feet to keep it from exploding on you. Even a mild ~300 amps was enough to cause some insulated wiring in my trunk to spontaneously combust.
||My point exactly. I've burned up 600a couplers while
running flux-core flat out on a rail car conversion. When I
say 'burned up', I mean they exploded in flames because of
the built-up resistance. The cable could handle it, but the
couplings couldn't. All that current has got to go