If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
Only way t get shocked from a single wire would be displacement current to surface of his body. Anyone has clue of average human self-capacitance?
Say it's 1nF, being hung on 25kV 50Hz AC wire:
Z = 1/6.28*50*0.000000001 = 1/0,000000314 - guy's capacitive impedance would be
3 184 713 ohms. Current is 25 000/3 184 713 = 7,8 miliamps. Probably not pleasurable but not lethal yet.
For birds and small animals with capacitance of just few tens of pf effect probably isn't bothering.
And he would also see an initial 'shock' once relatively high current dumps into his capacitance when he touches the wire (altough that wouldn't be the biggest problem at time)
Registered Member #193
Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022
"You have to remember that charge is relative..." If an object has more electrons than protons (in the nuclei of its atoms) then it has a negative charge. Potential is relative; charge is absolute. It's perfectly common for a person to get charged to much more than the few KV that this idiot by static.It stings a bit but it doesn't do any harm. 5KV is 5KV, it doesn't matter if you get charged from a nylon jumper or a power line.
Vigilatny Registered Member #17
Joined: Thu Feb 02 2006, 02:47PM
Location: NL
Posts: 158
rennoC evetS wrote ...
EVR: The arc between the helicopter and the line most certainly is due to the line voltage and the helicopter's capacitance. Think of the chopper as a humongous Tesla coil topload. I'm guessing this because
a) there's a helipad near my house and I don't see hot white arcs jumping to the ground any time a chopper comes in to land.
Depends on the power line(and perhaps the helicopter) whether the arc is from the helicopter or the line. A CH53E develops about 200 kV. I'd guess the helicopters used to service HV lines are designed to prevent static discharging(so no current flows once they reach line potential). That would mean they probably develop higher voltages than most.
Wikipedia wrote ... The job of the Static man is to use a grounding rod to attach to the hook so that the static electricity conducted by the helicopter is grounded out and does not end up killing a Marine.
Registered Member #193
Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022
"Anyone has clue of average human self-capacitance?" Estimates on the web vary, but the consensus is about 100 - 300 pf so the current would be less than a couple of miliamps. 20 feet above ground is more of a problem than 20KV above ground in this instance.
Registered Member #32
Joined: Sat Feb 04 2006, 08:58AM
Location: Australia
Posts: 549
You don't need to make the calculations. EVR made this point earlier: try charging yourself to something like this 25kV from a VDG. The situation, and hence capacitance, is different but things won't be worse.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Moron Alert
