High Voltage Line Attraction

Most experimenters in this arena are candidates for the famous Darwin Awards. Once the arc has struck, there is usually very little in the way of a viable human body worth saving. Pity the Undertaker who has to clean that up after the power has been turned off.

I think a well-established test rig will prevent such an hazard in which when there occurs a big attraction a fast acting mechanism will have a reverse direction force to save the human being...

I think you got me wrong. If not , excuse me in advance..

I ask about only an attraction force, before an arc strikes(at a distance larger than arcing distance).

In the UK, various Permit To Work systems are in place with a view to preventing humans coming into contact with high voltages. There is also legislation called the Health And Safety At Work Act 1974 that places obligations on both individuals and employers to have a duty of care for people at work and those that may be affected by that work, and which has given birth to those systems. Although contact with high voltage conductors does happen from time to time, the incidence is very rare.

There is no scope to develop equipment that would pull a human away from a high voltage conductor in the UK as the above legislation provides the protection framework that is needed to ensure that individuals go home to their families at the end of the work period.

By observation, one would have to say that HV lines repel all animals, not just humans.

One never observes birds, bats, anteaters, bison nor elephants dangling from HV lines, so it must surely be a repulsive force at work, regardless of the voltage/current.

Never having been south of the equator, I can only attest to this in the northern hemisphere, and only at 60 Hz.

It works with 50hz at 36deg S latitude also.

But try urinating on a 5000v agricultural electric fence and you will see if it is attractive or not.

There are several videos on YouTube demonstrating this effect!!!

One is here:-

http://www.youtube.com/watch?v=XH3GHxNpnoQ

http://www.youtube.com/watch?v=oLxr70dcZ-E

My dog together with another touched such a fence with their noses, mine came back to me REALLY upset for comfort. The other dog ran off and was killed on the Autobahn.....at least 4 miles away.....sadly.

...repulsion by observation, fencing, notices, barbed wire, inaccessibility, etc., etc...

I could never resist the temptation to point my finger at the collages Van de Graaff generator.

I knew it would bite me, so there must be some (masochistic) attraction.

Dang! Candidates for the Darwin Awards must now come from elsewhere... ;-)

Some people have no sense of adventure.

The Wimshurst machine did hurt, that wasn't deliberate.

Tesla wands are great toys, so long as you know what you are doing.

This would suggest that there is no such force - or if there is, it's tiny.

so I wish I could learn the physical explanations of the repulsive force.

I had asked my question in two case.

No load line and nominal load line (no current flowing, rated current flowing lines).

If there is such a repulsion, is it due to current or voltage. If there is why repulsion?

Sir,

Magnetic fields created by alternating current are generally only attractive to ferric-type materials and repulsive to certain material such as Aluminum. As far as I know the human body (even though our blood contains iron) is not measurably attracted nor repelled by the magnetic field.

The electrostatic field will attract if the charges are opposite polarity and repel if they are same polarity. Since most power is distributed in an AC form, the polarity of the wires is switching from positive to negative and back at the line's frequency (50 or 60 Hz typically). I doubt that a human body, in normal environments, is going to have any significant AC voltage; therefore there is neither attraction nor repulsion due to electrostatic effects.

I realize that many of the posts in answer to your question have been written with "humorous" answers based on the very great danger inherent when one is anywhere near to high-voltage conductors.

--JMM

Review electromagnetic theory. AC voltage and current should provide no net attractive or repulsive force to a nearby human. Regardless, keep a SAFE distance to avoid induced voltages, currents, or lethal direct arc flashes.

While a bird can safely perch on a high voltage line, I've seen many do so, I'd bet it becomes very uncomfortable for them when the voltage is high enough to cause corona discharge from their beaks.

so what if this force is so huge that at the first cycle in which the human body is exposed to this force , the body get into the hazardous region for arcing.

So what would you say if this current were direct current. What would this force be?

Repulsive or attractive?

If a human body is that close to a high voltage line, it's Game Over. Self-cremation. Half-a-day-out with the Undertaker, assuming enough can be found to fill the coffin. Misery for family and friends. That sort of thing. So, does it really matter whether the force is repulsive or attractive, in the slightest?

Is the message getting through yet?

The mere thought is repulsive!

GA. Thanks for sharing that. Thanks for being alive to share that. :-o

Your real life experience of accidentally getting in contact with HV AC and HV DC should be lesson to all engineers and all the three rules you said are meant to be followed. One of my college got electrocuted in 11 kV bus he was trying to inspect one side of the bus keeping the other side of the bus on, but he accidentally touched the live side of the bus, his hand was thrown out but got severe burn injuries.He was also lucky like you to survive the shock.In our safety operation and maintenance of electrical distribution permit system is followed where in the staff and technician working on line or substation maintenance have to obtain written permit from he substation operation in charge which he provides only after switching off the required feeder and earth the system by earth roads and issue the permit .After completion of the work the in charge of the work return the permit certifying that the work is completed and all men and materials and tools are removed and line is safe to be charged. The operating staff will energise the feeder only after the permit is closed.This system is working satisfactorily and electrical accidents are avoided.

Very Valuable input on this topic. I will add following principle in the sequence it shall be followed when starting work on Electrical Equipment:

SIDE

S - Switch off (Open a circuit breaker).

I - Isolate (draw out the Circuit breaker or open its GOD - group operated disconnect or also called in some Utilities Isolator).

D - Dump any stored charge (by shorting both terminals of a capacitor or inductor. Recent example is Live tank CT which is supported on a insulator was discussion of very recent post. This tank can store energy even after isolation).

E - Earth. (permanently put clamp with visible bare earth lead or if insulated it shall be transparent sleeve. One Earth clamp shall be at either end of job piece. Cross section of earth conductor shall be thick enough to withstand maximum short circuit level of the Electrical System we are working on. So that even if someone accidentally switches on the supply - the protection will trip and Personnel working shall remain on Earth Potential as either ends of work area were connected to earth).

So all my friends working in Electrical Maintenance shall "REMEMBER S I D E TO PUT ASIDE ANY CHANCE OF ACCIDENT"

...and even if it says on the Permit that it is dead, and the test gear says that it is dead, always take the opportunity to select the oldest spanner in the toolbox, cover the face, and toss it onto the connection before touching it, just in case.

And the spanner will evaporate spreading all over molten metal which may burn the cleaver guy throwing spanner.
Pl read my post carefully - when you are using earthing clamp with cable of size to withstand the max. short circuit current through hot stick and when the link between live terminals and earth is a visible conductor - you need not to through a spanner and it is much safer to use earting kit described above and designed for the purpose.
Best of luck - never play with electricity and/ or take any chance with safety.

Did it say it was dead on the Permit?

The repulsive force is cause by the intelligence of the person being repulsed.

The inverse is probably true as well.

if the human is grounded.........he becomes a fuse able link!

Yep. An earth-fault self-clearing device, in fact. :-O

then to be caught by the line due to muscle contraction , we must contact the line at the beginning.

So you too, do not say that there is no such a repulsion or attraction by the line carried out on human body if you get near the line up to a certain proximity.

I think no one claim to see such an incident right?

I think you want to know the safe distance for working from a high voltage source. The safe distance would depend on many factors, humidity being most important.

In monsoon we have observed that the overhead high voltage conductors causing mild shock to persons walking underneath with an umberella on a rainy day(distance of over 30ft).

There must be some formula about voltage and safe distance in relation to humidity.

The city commuter can testify to the fact that an umbrella held up in the rain while waiting for a train beneath a 25kVAC overhead railway traction power conductor can cause serious tingling when brought into contact with the head.

The highest voltage I have worked on is 500KV and I have never knowlingly expereinced any attraction or repulsion forces.

This being said; At voltages above 22KV there is static phenonom that creates an unnatural sensation wherein the body hair is affected.

Occasionally when in close proximity to voltages above 250KV and when/if any sudden loud noise is experienced, little or large drops of sweat trickle down the inside of some people's legs

There may be an attraction or repulsion effect there that is not strong enough to be realized by most humans.

As far as safe distances from energized devices is concerned: A good source for information is The National Technology Transfer Inc at: www.nttinc.com and the NEC Hazard Approach Boundaries Table(s).

Performing a search on "HV Electrical Contact" via the internet and on such sites as the University of Chicago and the University of Colorado may yield more significant scientific testing DATA results.

"Sweat"???

High Voltage usually attracts IDIOTS lol. ( present company excluded ? )

Many descriptions and videos exist.

There is a physiological repulsion. As an apprentice I received a shock from an open frame board. My RH little finger got the brunt of it. Ever since then if I approach live open gear it tucks itself in to the palm of my hand out of harms way.

I know we're not supposed to work on live gear but we did, it was normal practice then.

Like SHOCKISCAN I've walked (limped) away from 10KV line to earth, it bloody hurts. I still limp to this day after I was thrown against the wall, the wall came out of it better than I did.

No there isn't. If you would like to know what an all encompassing electrical shock is like just ask someone who has an implanted heart defibrillator that has activated at some time. It is an all-encompassing overpowering internal shock to the body that makes the heart stop and restart and activates most of the muscles in the body all at the same time. To say the least, you certainly know what has happened and your body feels like someone has stuck you with a 20KV knife. It neither attracts or repels the human body. It does it all at the same time.

Go ahead, ask someone who has experienced it. Get the information first hand from the one who really knows.

Good Luck, Old Salt

No. Observe that birds land on and take off from high voltage lines without being affected.

It think you are assuming AC will attract objects such as a static charge. They are not the same at all. Static charges build and negatively charged objects will attract positively charged objects.

I do not think AC attracts or repels anything. I have seen birds perch on relatively high voltage lines. I am sure animals can sense the voltage either by sound. We now know at least some birds can sense magnetism and know where magnetic north is. Animals keep clear of unfamiliar things and live longer that way.

I too know of someone that survived 440V, not truly high voltage but still a killer. Again the muscles that tensed made him jump with inhuman power saving his life.

All high voltage lines generate an EMF around the conductors. You can detect it with an antenna connected to a scope. The scope can then measure amplitude, frequency, and spectral shape.

The human holding the antenna is subjected to the same EMF. No one has ever proven that such EMF is harmful to humans, but no one is building houses close to them any longer!