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Author Topic: Ice Bucket Challenge & High Voltage Power Lines  (Read 9785 times)

Mike Sokol

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Ice Bucket Challenge & High Voltage Power Lines
« on: August 22, 2014, 07:30:36 AM »

A firetruck's ladder got too close to a high voltage power line during an ice bucket challenge and an arc jumped to the ladder, injuring the four firefighters in the bucket. I'm speculating that all the water mist in the air made it easier for the arc to jump a longer distance than normal. But until I see a report on just how close they were to the line, it's only a guess. In any event, make sure you know where ALL overhead lines are before you put anything up in the air. I've driven Pettibone lifts a lot of times that could easily have touched a power line. I'm usually pretty good about watching for power lines, but I'll be REALLY careful after seeing this accident.

Mike Sokol

 A charity stunt that has grown into a social media phenomenon went terribly wrong for four Kentucky firefighters when a fire truck's ladder got too close to a power line after they dumped water on college students who were taking part in an "ice bucket challenge."

Campbellsville Police Chief Tim Hazlette said the power line was never touched Thursday morning, but it carried such a high voltage that it was able to energize the ladder truck, shocking the firefighters.

The two in the bucket were at a hospital burn unit early Friday. One was in critical condition and the other was in fair condition, the hospital said. The other firefighters were treated and released.

The firefighters had just taken part in the challenge that helps raise money for ALS research. They dumped water on the Campbellsville University's marching band, but most of the students had already left the area and no students were hurt.

University nursing student Julie Smith said she was nearby and spoke to a couple of friends who witnessed the firefighters being shocked and said "they are taking it really hard."

"It's tragic, I feel for all the band members who were still there when it happened, that they had to see that," Smith said. Smith later led a prayer vigil with about 100 people on the campus Thursday night.

Power was knocked out for about an hour to 4,500 customers, including the school, said Natasha Collins, a spokeswoman for Kentucky Utilities, which owns the line.

The ice bucket challenge has been sweeping social media websites. The ALS Association said it has raised more than $41 million.

Police said Capt. Tony Grider, 41, and Simon A. Quinn, 22, were in the fire truck bucket. Grider, a 16-year veteran of the department, was in critical condition at the University of Louisville Medical Center Burn Unit. Quinn, a part-time firefighter, was listed in fair condition there.

Firefighter Keith Bricken, who has worked with Grider for about three years, said he was a tough firefighter who trained colleagues.

"He's real outgoing. He loves to help in any way he can," Bricken said.

Also injured was Capt. Steve Marrs, 37, who has been with the department for 11 years, and Alex Johnson, 28, who has been there three years.

Campbellsville University, a private college, is a Christian institution that has about 3,600 students, according to its website. It is about 65 miles south of Louisville.

"A number of our students, of course, the entire marching band, witnessed the event and so we're concerned about them and the tragedy of this accident," university president Michael Carter told WHAS-TV ( http://bit.ly/1nfKGZ6 ).

http://abcnews.go.com/US/wireStory/ice-bucket-challenge-awry-firefighters-hurt-25075552

Stephen Swaffer

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Re: Ice Bucket Challenge & High Voltage Power Lines
« Reply #1 on: August 22, 2014, 09:09:53 AM »

IIRC the minimum clearance from overhead allowed by NFPA 70E is 10 feet-and it goes up from there depending on voltage.  Common 4000-7000-13K lines won't jump that far, but you have to allow for line movement as well as equipment sway.  Even though my bucket truck is insulated for70kV, I heed that 10 foot "line" religiously.  Non insulated stuff - aluminum ladders, truss etc should never be where they can fall within that distance-and personally I would probably double it unless I had a very good pressing reason.

Since the students had left, I wonder if they just let their guard down since they were done and packing up?  That is way too easy to do.
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Steve Swaffer

Art Welter

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Re: Ice Bucket Challenge & High Voltage Power Lines
« Reply #2 on: August 22, 2014, 10:36:48 AM »

Even though my bucket truck is insulated for70kV, I heed that 10 foot "line" religiously. 
20 gallons of water is around 160 pounds, once two guys throw that much weight off there would no doubt be quite a swing at the bucket end of a ladder, which could put them a lot closer to the arc zone than when they started, even more so if they had brought up several containers of water to start with.
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John Roberts {JR}

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Re: Ice Bucket Challenge & High Voltage Power Lines
« Reply #3 on: August 22, 2014, 11:05:09 AM »

I've told this story before, but back in the '70s some lawyer asked me to be an expert witness in court when his client claimed that voltage had jumped from the power drop going to his house to his aluminum ladder knocking him off it.

Since those power drops are two opposite polarity legs of 120V, I advised the lawyer that his client would have to be so close to the wire that he was effectively touching it. I did not get hired to say that in court. :-)

Of course higher voltage lines are a different story and I would say the spacing they use up on the poles is by definition generally adequate, but these high voltage lines deserve a lot of respect and distance.

JR
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Bill McIntosh

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Re: Ice Bucket Challenge & High Voltage Power Lines
« Reply #4 on: August 22, 2014, 11:14:51 AM »

20 gallons of water is around 160 pounds, once two guys throw that much weight off there would no doubt be quite a swing at the bucket end of a ladder, which could put them a lot closer to the arc zone than when they started, even more so if they had brought up several containers of water to start with.

Pictures I saw looked more like they were using the hoses and spraying the students, but that detail was not included in the reports I have seen.

Some of the reports noted the lines were carrying 65kV. 

FWIW my daughter attends Campbellsville U, but she is not on campus yet, so I have no first hand knowledge.

Link to a local TV news page with some photos: http://www.wave3.com/story/26338512/campbellsville-firefighters-injured
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Andre Vare

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Re: Ice Bucket Challenge & High Voltage Power Lines
« Reply #5 on: August 22, 2014, 11:48:20 AM »

Link to a local TV news page with some photos: http://www.wave3.com/story/26338512/campbellsville-firefighters-injured
The details are varied right now. The 4th paragraph in the news item that you linked starts with this sentence:

Sources say the incident happened when the fire truck's aerial basket touched power lines.

Andre
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Bill McIntosh

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Re: Ice Bucket Challenge & High Voltage Power Lines
« Reply #6 on: August 22, 2014, 12:27:40 PM »

The details are varied right now. The 4th paragraph in the news item that you linked starts with this sentence:

Sources say the incident happened when the fire truck's aerial basket touched power lines.

Andre

Yes, they are not consistent.  Some news accounts quote students as saying the bucket or the ladder touched the lines.

The KY State Trooper in charge of the investigation stated that the ladder did not touch the lines, but there was arcing when it passed close by.  One account states that Capt. Grider was hit directly by the arc. 

Regardless of what happened, he remains in critical condition in the burn unit here in Louisville.
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John Roberts {JR}

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Re: Ice Bucket Challenge & High Voltage Power Lines
« Reply #7 on: August 22, 2014, 01:26:10 PM »

There may be some CYA going on in statements after the accident but you do not need to literally touch 65kV to draw an arc, I suspect you do need to get within a few inches. Some spark plugs run up into tens of kV.

A rouge event like a static discharge could ionize the path like lightning's up-strike before the down-strike. Once there is a conductive path the current could sustain the larger arc. That said I expect most bucket trucks to use anti static treatments.

Even if you need to get pretty close, why risk it?

JR

 
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Mike Sokol

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Re: Ice Bucket Challenge & High Voltage Power Lines
« Reply #8 on: August 22, 2014, 03:00:28 PM »

A number of the reports I've read from the BIG power companies putting high tension lines (110 to 250+ KV or more?) over farm fields suggest that a 14 ft minimum clearance must be maintained from these lines. There's supposed to be a 28 ft minimum clearance to the ground and since road vehicles are limited to 13' 6", then you should be able to drive under one without danger. However, they warn you that standing on top of a 13' 6" vehicle under a 28 ft high power line can result in an arc flash-over to your head. Ouch... :o

Every year there's reports of farmers and construction crews who drive conveyors and ladder trucks with the booms up directly into power lines, with many arc-flash and electrocution deaths. I really don't want to know how close you can get, but certainly the 14 ft distance would be my absolute minimum. But it's really hard to judge and I'm not going to get my tape measure out.

Stephen Swaffer

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Re: Ice Bucket Challenge & High Voltage Power Lines
« Reply #9 on: August 22, 2014, 05:34:27 PM »

There are different types of bucket trucks-some are insulated others are not, my guess is a telescoping ladder would be very difficult/impossible to insulate effectively.  A couple of things working against the firefighters-stabilizer arms firmly grounding the chassis (chassis should be grounded anyway), and secondly no PPE.   When working, no lineman-or firefighter -would be in a bucket without a hardhat (designed to insulate) providing some protection from the highest/closest point to the power line. My guess is that SOP during a fire would be a spotter watching the lines for clearance. Also, turn out gear would provide protection from even a severe arc flash .  Not trying to blame the injured-they are obviously good people doing a good thing-just observing a lesson for all of us.  Even when we take time off for fun, hazards do not, so we need to be aware of safety even when "playing".

I agree with Mike on staying clear.  My personal comfort zone?  In a truck insulated and tested to 70 kV,  I feel like I can safely-with proper PPE -work on circuits not exceeding 120 volts to ground so say a 500x safety factor? :)   
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Steve Swaffer

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Re: Ice Bucket Challenge & High Voltage Power Lines
« Reply #9 on: August 22, 2014, 05:34:27 PM »


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