Strange situation

[TRAMPLINEMAN]

Good morning.

[Brooks]

Working on a new 69KV line about 36 miles long. About half of the line is thru the desert and the other half is thru the forrest with no parallel lines, no hot crossings and never been energized. New line is 336 single conductor. Working on a 90 degree double dead-end making up jumpers. To the south, about 10 miles is already jumpered thru. To the north, about 20 miles is jumpered thru. So, we'll be picking up about 30 miles of wire, no big deal. The dead-end, a 60' steel Meyers pole. 8 guy wires, 4 in each direction with fish rod in each. One for the fiber and one for each phase. The fiber is caught off in dead-end shoes which are grounded to the pole. Each phase, from the pole out, has a sister eye to an H shackle to a 69KV polymer to a pistol grip shoe. When we arrived at this location, I told the apprentice we'll be picking up alot of wire so we'll have to be careful. We were going to make up jumpers so we put a ground from each side of the dead-end to the pole and put another ground from line to line. I had to role the sister eyes up a little to get the pistol grips to lay horizontal. I stuck my spud crescent wrench into the sister eye to role it up and while rolling, the tip of the spud contacted the pole. When this happened, I heard a snap, like putting battery jumper cables together. I also got hit with the worst case of induction I've ever encountered. I remember screaming like a little girl and thru my spud about 30 yards away. I pulled my left glove off and half of my left hand was ghost white. My ring and pinky fingers were twitching uncontrollably.

Now, I can't think of anything we did wrong. I can't think of anything we could have done differently. I can't see why this would have happened. Anybody have any ideas or suggestions? Thanks, Mike

Think capacitor - lots of wire running above the earth, wind, static....

equipotential grounding - keeps you safe...

[harley]

If the steel pole had core coat at the bottom the pole will not be a good ground. Also you might want to test your grounds to make sure the wire in the lug or clamp has not corroded. We tested all of our grounds and a vast majority of them failed. We have replaced all of our grounds now.

[Powerline]

Could it be lightning?

[OLE' SORE KNEES]

Depends on if you had on Bare-Hand boots(shunted out) you would've been the same potential, regular work boots you're probably at a difference of potential even though grounded.Sometimes even though you're grounded on Hi-Line there is a certain amount of circulating current,a type of loop thru the grounds.

[659Lineman]

Were you working out of a bucket? Insulated boom or non insulated boom? Bucket grounded? If it was a steel boom, makes for a really long ground path.

[dbrown20]

I mostly agree with that theory. An unconnected line will pick up a charge due to wind etc. Worked on a piece of 345 once and although it was grounded the clippers began to complain of it biteing them more and more. The supt. said the farther you get from the grounds the worse it will be. More grounds were added and that cured the problem. dbrown20

[toptie]

You really need to follw up on some equipotential grouding. I think either A.B. Chance or White might have a really educational film on this. It will FREAK your FREAK.

[old lineman]

I know all about EPZ grounding. Went thru two classes.
We were in an insulated bucket.
We had grounds on our structure and a set of grounds three spans down in each direction.

Anyone who wants to purchase a real good Equipotential Grounding and Bonding video should look at the www.eusa.on.ca web site. The video is current and is designed as a teaching tool.

Tramplineman, I am trying to visualize all of your steps in sequence.
The first thing I must ask is,"was there a break in the conductors at your structure. If there was you should have married both sides of the structure together first. That would equalize potentials between one side and the other.
You said that the conductors were grounded on either side of your work site. In reality they are meaningless, both for eradicating induction or bringing both sides equal. There will always remain a difference between one side and the other.
At the site grounding is the only way to attack this job.
Next you should have installed the ground clamp to the structure and the other end to the conductor with a shotgun.
Seems elementry but if you followed that procedure and got a poke from contact between the conductor and the structure something is wrong.
The first thing I would suspect is a bad connection either at the conductor grounding clamp or the other end.
Let's face it even if the grounding was poor at the structure (the grounding at the base or the sky wire) once you've brought the conductor and the structure to the same potential you cannot receive and electrical shock.
"No difference in potential, no possibility of an electrical shock"), the bird on the wire concept.
What I'm trying to say is that once you've connected those two elements together it might still have a current with a value above zero but it can't flow though you because it's an EPZ.
We used to test our grounds under load and rarely did we find a good set of grounds. In fact we changed all of our grounding clamps to threaded ferrels because the smooth compression type connectors failed repeatedly.
With a threaded ferrel once tight they can be locked with a lock washer and jamb nut.
Never use solder for grounding connections because the fault current will heat the connector instantly and blow out the solder leaving a loose connector that WILL fail to carry enough current to trip the protection. In addition the flying cable could cause injuries if it breaks loose from the clamp.
The Old Lineman

[OLE' SORE KNEES]

Some power companies in transmission have gone to bracket grounding close to the work and then use a personal ground(single point) right on the conductor where you are working.

[Bull Dog]

The only thing i can think of is it was grounded to a bad ground some how. Is this a possibility? I grouded a hot phase one time and did not know it till i looked again. Removed ground from phase and nothing happened. Was lucky i know.

[old lineman]

old lineman,

When we first got to the structure, there was a break in the conductor. The first thing we did was install the cluster mount to the pole. Then we attached a ground from the cluster to each side of the dead-end. Another ground was attached from line to line. I know two grounds should have been sufficient, one from the cluster to the line and the other from line to line, but we installed three anyway. The grounds were all installed with a shotgun.
All our grounds are the threaded ferrel type. They were just sent out from being tested. We even went so far as to wire brush the pole where the cluster attached.


It sounds like you did everything right, but something was wrong somewhere. I know that you feel that you could have gotten away with just one lead and you could have because the current flow would be small compared to a fault current, but still enough to be lethal.
Perhaps you've be breathing too much of that smoke from your truck. Ha, Ha.
The Old Lineman