View Full Version : Tree Worker Electrocuted In Haddam Conn
10-24-2007, 06:07 AM
Officials: Man Was Standing Near Truck That Touched Power Lines
POSTED: 1:37 pm EDT October 22, 2007
UPDATED: 7:06 pm EDT October 22, 2007
EAST HADDAM, Conn. -- A tree trimmer was killed in East Haddam Monday morning after being electrocuted, according to police.
The man has been identified as Peter Sokolovsky, 30, of Brooklyn.
State police said Sokolovsky was on the ground in front of the bucket truck when it came in contact with or near power lines after 9 a.m. An electrical surge traveled from the truck to the ground and into Sokolovsky, officials said.
Connecticut Light & Power told Eyewitness News that Sokolovsky was part of a five-person crew of contractors working for Texas-based ABC Tree Pros.
"It's a very, very tough day and our hearts go out to the family of the young man," said Mitch Gross of CL&P. "He was just doing his job and it looks like it was an accident."
CL&P told Eyewitness News that the trees were being cut back so that power lines can be upgraded for a new elementary school.
Sokolovsky was pronounced dead at the scene and another man, who was in the truck's bucket at the time of the electrocution, was transported to an area hospital for evaluation.
Police closed a stretch of North Moodus Road during the investigation.
Police and the Occupational Health and Safety Administration are investigating.
10-24-2007, 05:28 PM
So another ground borne voltage gradient death that probably caused no internal injury other than putting the workers heart into a state of fibrillation. Do I need to say the rest?
10-25-2007, 06:33 PM
It was not a voltage gradient, from what i heard there were entrance wounds on his hand and abdomen and exit wounds on his foot. He grabbed the truck while it was energized. And not to get into too great a detail, but supposedly he was also on fire.
10-25-2007, 11:05 PM
10-26-2007, 06:18 AM
Understanding step potential is one of the biggest challenges in maintaining worker protection. A step potential is defined as the voltage difference between two points on the ground, separated by the distance of one pace or 1 meter.
When an object such as a pole accidentally makes contact with an exposed live conductor, electrical current flows into the earth (ground fault). At the point where the pole touches the ground, there is a rise in voltage relative to any earth farther away from the base of the pole. This current can take many paths as it flows through the earth. As the current flows away from the pole, the earth acts as a resistor, usually lowering the voltage as it gets father away from the base of the energized pole.
This voltage also has been called ground gradients, potential gradients or step potentials. It behaves like a ripple in a puddle after dropping a stone in the middle. As the ripple moves away from the base, a voltage difference develops between each ring of ripples, typically decreasing with each ring farther from the center.
Step potentials (accidents) occur when a worker gets one foot on a high-voltage ring near the base of the pole and the other foot on a lower voltage ring farther away from the pole.
When a fault-to-ground occurs, the current will flow through the earth back toward the source through the easiest paths available. In other words, during a ground fault there is no way to know where and how far the ground gradients will travel. The return flow can be into the earth, back up any ground wires to the neutral, along fences, creek beds and so on. If the derrick truck is grounded to the neutral, then the return path for much of the current could be back to the truck and up to the neutral.
If anything makes contact with a high voltage power line, such as a tree or an uninsulated boom on a truck, or if a broken power line falls to the ground or lands on a vehicle, electricity will flow to the ground and spread out in concentric circles like the ripples in a pool of water.
Voltage is very high at the point where electricity makes contact with the ground. The level of intensity decreases as the distance increases from the point of contact. Zero voltage is approximately 10 metres (33 feet) from the point of contact.
Due to the difference in voltage as one moves towards or away from the source of electricity it is possible to "step" between high and low voltage differences. As the human body is usually a better conductor of electricity than the ground the electricity can flow between the feet through the body with sometimes devastating results. This is referred to as "step potential".
Trees can be very conducive. If a tree comes into contact with a high voltage power line and a person is touching the tree, or touching a ladder leaning against the tree, there will be a high to low voltage difference between the person and the ground. This will force electrical current to flow through them to the ground and may easily result in serious injury or worse. This is referred to as "touch potential".
Shuffle or Hop
If the ground becomes energized, hopefully youre wearing dielectric footware, if not, you can avoid shock by keeping your feet close together and taking short, shuffle-like steps, never allowing the heel of one foot to move beyond the toe of the other, until you are clear of the energized area, approximately 10 metres (33 feet). Alternately, you can hop with both feet together, again to a minimum distance of 10 metres (33 feet).
10-26-2007, 09:07 AM
Well said CPOPE.
This appears to be a case of contact voltage as opposed to step and touch potential where there were entry and exit wounds.
If you are going to work in the primary zone you should probably have insulated booms, and for Heaven's sake, if you are on the ground when the truck is in the primary area avoid contact with the vehicle.
My thoughts and prayers are with the family.
10-26-2007, 01:44 PM
Yeah, from the perspective of the entry and exit wounds it suggests a fairly massive current flow.
So just for perspective. An 11kV line drops on the grounds and if the voltage did gradient out to near zero at 33 feet then that would still mean a potential difference across the ground of over 300 volts per foot. Assuming a stance with the feet 24" apart that would equate to about 600 V across the body minus any insulation value of footwear. Footwear tends to end up damp through sweat (which is highly conductive) so a good amount of current is likely to be forced through the general body mass.
I did an experiment once that involved passing a limited AC current up one leg and down the other. Even at just 30mA the legs locked and balance was lost. In that scenario a hand placed on the ground as a worker fell would then create another route through the body of even greater distance and potential. Perhaps 1kV or more.
10-26-2007, 06:42 PM
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