ARC Distance

[jackjet]

Could someone please tell me how far 765,000VAC under a 3000 ampere load can arc ? I suppose once it started you could "pull" it out quite aways right?
This really is a serious question.

Thanks guys.

Jack Williams
Hesperia,Ca.
Want to be a powerlineman someday before I am too old...52 years old.

[500 KVA]

Good luck with that!

There may be some formula out there to give you an accurate distance. I don't know it. There are alot of variables though.

Where do you come up with 3,000 amps? You need to know how much fault current is available at the location of the arc. How far is the fault location from the feed? What is the fault the result of? Phase to phase or phase to ground?

In other words, are there any other conductors that will become involved should an arc begin? Will they also add to the arc?

Altitude also plays a factor. The density of the air surrounding the conductors. How much ozone will be produced in the arc, and how far it will be able to travel from the source of the arc before it dissipates?

Conductor size and composition. 1,000 MCM Copper, 2,000 MCM Aluminum?

How long will the protective breaker stay closed before locking open? They tend to open and lock out very quickly on EHV transmission faults. Will the breaker operate properly when needed to?


Just food for thought until you get an answer from somebody on here who might know what you want to know.

[wtdoor67]

Jack I think you're jacking with us. Go to the nearest university with an electrical engineering program and pose this question to them.

If you get into an apprenticeship you should be able to retire about the time you make journeyman. Good luck.

An arc of that voltage and amperage would probably never go out in open air unless you had about a mile to pull it.

[Ski_Digger]

Serious Question
What is so [U]Serious[U] about it?
Sound like I would like to hear the story behind the question.
All I know is I would not like to be close to it or have it be my falt for having it.
Good luck
Ski

[old lineman]

Could someone please tell me how far 765,000VAC under a 3000 ampere load can arc ? I suppose once it started you could "pull" it out quite aways right?
This really is a serious question.

Thanks guys.

Jack Williams
Hesperia,Ca.
Want to be a powerlineman someday before I am too old...52 years old.


In a laboratory setting the general measurement is 1 inch per 10,000 volts so 76".
Factor in all the variables and you have a potpourri.
Wind, humidity, current, temperature, etc.
The Old Lineman

[buzzit125]

Those men on the flying platform fuzz on to 750,000 volts with a wand.
The arc looks to be about 2.5 to 3ft before they make contact to the conductor.
The size is 1750 ACSR
Relative humidity at 50%
Dew point at 3
Clear skies, 75 deg f.

[old lineman]

Those men on the flying platform fuzz on to 750,000 volts with a wand.
The arc looks to be about 2.5 to 3ft before they make contact to the conductor.
The size is 1750 ACSR
Relative humidity at 50%
Dew point at 3
Clear skies, 75 deg f.

I barehanded 735,000 volts and you can't count that arc because it was just arcing to a suspended object be it human or otherwise.
Approach with a dead short (ground ), thats another kettle of fish.
The Old Lineman

[oldlineman55]

The old rule of thumb is 1 inch per every 10,000 volts in clean air. So 750,000 volts would be 43 inches. I used to barehand up to 500,000 (phase to phase) and when we took the bucket towards the conductor to check for leakage across the boom it would start arcing what seemed to be about two feet.
500,000 volts phase to phase computes out to 288,683 volts phase to ground so that would arc at around 28 inches. Of course I don't think I would reach out from a tower and get anyway near that.

[wtdoor67]

The question posed here is a load arc, not a charging current. Some difference I think.

[Squizzy]

I seem to recall the insulation value of air is 2.14kV per millimeter. That would be for an arc from cunductor to conductor and not including an arc that has formed and ionised the air which will then get alot longer especially as hot air rises......
http://www.youtube.com/watch?v=A5YxdRfAe14

[jackjet]

Thanks guys for the replys-

Belive it or not ,I like experimenting with HV electricity-I have neon sign transformers (15kvac-300ma) - would like to build a really LARGE Tesla Coil- with a output of at least 900kv.I know that would arc a long way....right up the street there is a 765 kv line - and I am trying to figure how to do this without getting electrocuted. I can hear the corona and static when I stand under it. How can I do this ? Please help. Maybe a long insulated pole with a wire grounded and then I could pull the arc out from one of the phases ?
Thanks.
Jack

[wtdoor67]

Tell you what Jack. If you intend to try something like that, would it be alright with you if I purchased an insurance policy on your life?

Please arrange for witnesses so I can collect as there may not be enough left of you to identify.

[jackjet]

Tell you what Jack. If you intend to try something like that, would it be alright with you if I purchased an insurance policy on your life?

Please arrange for witnesses so I can collect as there may not be enough left of you to identify.

Why can't someone tell me how to do this? Is it really that dangerous ? With enough insulation - isnt the risk minimal ?
Thanks.
Jack

[cololinehand]

Jack,
Have you noticed where you have posted your supposed question? That's right, in a SAFETY FORUM.

We as J/Ls try to NOT create an arc. You sound like a first class moron you when you say:

"I know that would arc a long way....right up the street there is a 765 kv line - and I am trying to figure how to do this without getting electrocuted. I can hear the corona and static when I stand under it."

If you haven't noticed in this SAFETY FORUM, there have been a rash of ACCIDENTS that have happened to professional lineman and line apprentices. What you are purporting to try is an INTENTIONAL close call that all of us avoid like the plague.

Please do your family a huge favor and find another hobby.

C

[old lineman]

Jack,
Have you noticed where you have posted your supposed question? That's right, in a SAFETY FORUM.

We as J/Ls try to NOT create an arc. You sound like a first class moron you when you say:

"I know that would arc a long way....right up the street there is a 765 kv line - and I am trying to figure how to do this without getting electrocuted. I can hear the corona and static when I stand under it."

If you haven't noticed in this SAFETY FORUM, there have been a rash of ACCIDENTS that have happened to professional lineman and line apprentices. What you are purporting to try is an INTENTIONAL close call that all of us avoid like the plague.

Please do your family a huge favor and find another hobby.

C


Amen to that brother.
To every action there must be an objective, what is it? Suicide.
The Old Lineman

[wtdoor67]

Jack, why don't you start out with a low voltage and work your way up. Say maybe 480 volts, then 2400 volts, then 7200 volts, then maybe 14400 volts, then about 12 KV, then 19.8 and so on.

When you get up to about 155 KV, give me a call. I'll come watch. If you make it to 765 KV, I'll bring my video camera, I know damn well Leroy ain't never seen an arc like that.

If you get hung up on anything technical just contact Swampgas. He's real technical.

[500 KVA]

You have to be, or you are the stupidest Mother Fu$ker alive at the moment!

Where did you get this idea? You mess around with 120 Volts and under the right circumstances you will die.

I would have never offered anything to you if I knew you would be some stupid idiot with the brain the size of a pea.

DO NOT DO IT! STAY AWAY FROM IT, AND NEVER ATTEMPT IT AT ANY VOLTAGE!

[rowdy2133]

I would just like to add to the general opinion of the group, if you ever try this let me know, it would be the best acr/flash video ever made, too bad it would involve you! This is a website for lineman and aspiring lineman, you dont sound like either, of course thats just my opinion....Rowdy!

[Squizzy]

Is this what you had in mind?
http://www.youtube.com/watch?v=bdup-WrnLng&feature=related

[jackjet]

Is this what you had in mind?
http://www.youtube.com/watch?v=bdup-WrnLng&feature=related

Thanks Squizzy,
That is just what I want to build. Thanks for the kind reply. I wonder why the other linemen on here are so mean?

Anyway thanks again.

Jack

[jackjet]

Jack, why don't you start out with a low voltage and work your way up. Say maybe 480 volts, then 2400 volts, then 7200 volts, then maybe 14400 volts, then about 12 KV, then 19.8 and so on.

When you get up to about 155 KV, give me a call. I'll come watch. If you make it to 765 KV, I'll bring my video camera, I know damn well Leroy ain't never seen an arc like that.

If you get hung up on anything technical just contact Swampgas. He's real technical.

Thanks for your answer.

Jackjet

[wtdoor67]

We weren't being mean Jack. I think everyone just thought you were messing with us.

Fooling with this stuff can get rather serious. Most have seen or know friends in this industry get either maimed or killed.

Plenty of house hold voltages will kill easily under the right circumstances. That's from 120 on up. If not killed outright you can get a severe flash burn just from the arc.

If you're serious go to your nearest college with an electrical engineering program and quiz them. There are many factors that govern a question such as yours. Many have already been alluded to.

[jackjet]

Thanks linemen for your answers.

I will leave the 765kv stuff alone - and build me a Tesla Coil.

Thanks again
Jackjet