Electrical Safety

[jimthefireman]

For some time at motor vehicle extrications there have been occasions where electrical wires have prevented us from taking action until the Utility company could arrive. More recently at extreme weather events where we had wires down all over the city, Fire crews were tied up just keeping scenes safe until overloaded Utility crews could arrive and make things safe.
What (if any) Insulated handling tools and/or procedures are used by firefighters to move wires when no better option exists?
Obviously waiting for the power company is best and safest, but sometimes that is not an option.

[fireman4949]

Many moons ago, we carried insulated linesman gloves (36,000 volt rated, IIRC) and hot sticks on a few of our trucks. To my knowledge, there was never any real training on their proper use, nor was there (again, to the best of my knowledge) any routine professional certification inspections done to insure their insulating properties were intact.

They were removed from service years ago, but I have heard various stories about some of the "old timers" using them to move energized power lines. It was only by the Grace of God, that none of them ever got fried!
I know one fella that used nothing more than a wooden pike pole to move a hot power line. He too, lived to tell the tale.

I've seen first hand what 14,000+ volts can do. I would leave the high-voltage stuff to the power company.

If you feel that it is absolutely necessary to have high-voltage equipment on your rigs, I'd strongly advise (very strongly) that you have the power company provide the necessary training, as well as provide the equipment and its routine testing/inspections.




Kevin

[jimthefireman]

We still carry the linesman's gloves, and they are tested regularly, We also carry a MODIWARK A/C detector and remote pole which could be used to move a wire if need be, but it does not grip or hold the wire which I think would be a necessity if you were going to guard against losing control and possibly having an accident.
We still woudn't pick up wires even wearing the gloves and I would hope no firefighter would go near a line of 14000 volts whatever he is wearing. Most of our problems are with 400 volt lines max.
I want to restate that the safest and best course of action is to wait for the power authority but in the very few occasions where immediate action is necessary I would like to know what options are out there.
I also agree that even with equipment, it would be best to get the power companies to do the training however, I am wary of being brushed off with the "that is impossible, just leave it to us" sort of reply that some may take and would like to be well enough informed to know the options in the debate.

[Bowbreaker]

I do not think any power company, at least not in my part of the world would instruct firefighters to move energized high voltage lines. There is to much risk. Our power companies policy is "we don't mess with their power and they won't mess with our fires".

I am an electrician and work closely with our power company. 6 of our 28 volunteer firefighters work for the power company, 5 as linesman. Our department does not and will not touch a power line until it is declared safe by the power company.

It takes more than gloves and a hotstick to safely isolate an energized high voltage power line. The line has to be off the ground and secured away from anything that can be energized. The power must be removed and the lines grounded to prevent an accidental re-energizing from happening before a downed line is safe to move.

In an emergency its tempting to try moving a power line but don't. It is too dangerous without the proper tools and knowledge of the system to take a chance.

Brad

[nmfire]

What (if any) Insulated handling tools and/or procedures are used by firefighters to move wires when no better option exists?

None and we don't do it. We had a 100K line down in the road next to an MVA last winter and we had to sit there for 45 minutes waiting for the power company to show up in a snow storm. It was quite the light show I must say, you could see the glow in the sky from almost 10 miles away.

[raricciuti]

A little off-topic, but...

I can't remember exactly where, but there is a utility company (both gas and power) in Texas that has a real "emergency response" division. A very well-equipped utility truck staffed by two technicians is available to respond to fires and crashes where there is an immediate need to shut off gas or power. And get this, it's an emergency vehicle (as in lights/sirens), and I believe the techs have EVOC training. Would be nice when you've got live primaries down on an occupied vehicle, or a gas fed fire inside a structure.

[ElectricHoser]

See also:

Energized Wires
http://forums.firehouse.com/showthread.php?t=69948

Pulling electric meters
http://forums.firehouse.com/showthread.php?t=58566

Why to call the Power Company
http://forums.firehouse.com/showthread.php?t=71941

Removing electrical meters
http://forums.firehouse.com/showthread.php?t=84176

In a nutshell: Never worth the risk. Wait for the professionals.

[dday05]

We have a Hot Stick ,but we treat every electric wire as it's hot just like everybody else.

[fdsq10]

When dealing with high voltage lines we should leave it to the power company to handle. Our policy is the same as a lot of departments wait for the arrival of the power company. We do not carry any equipment to handle high voltage lines. We have a good working relationship with Dominion Virginia Power. When they are requested for situations involving wires on vehicles or potiential hazards with high voltage lines they are not far behind us. Just remember with live high voltage lines on vehicles and the ground be aware of ground gradient current it will surprise you and your crew. Bowbreaker post should make your decision easier, great information. STAY SAFE!!!

I've had this idea that I thought about before, it's pretty simple. What if you took a long piece of rope and threw it under and past the downed line, and then had someone throw the end of the rope back over the line towards you. You could drag the line away from a wrecked vehicle assuming rope is a poor conductor while maintaining a resonably safe distance from the energized line. Is this feasible?

[Flochief]

Please don't try it. Can you tell how many volts is on the line? I work for a power company, on the power generation side. Leave moving the electric lines to the people that know, line crews. I know it is frustrating. Because I have to wait as well on my volunteer dept. We have been waiting up to 3 hours.

[ElectricHoser]

I've had this idea that I thought about before, it's pretty simple. What if you took a long piece of rope and threw it under and past the downed line, and then had someone throw the end of the rope back over the line towards you. You could drag the line away from a wrecked vehicle assuming rope is a poor conductor while maintaining a resonably safe distance from the energized line. Is this feasible?

No way, don't do it. I also work for the power company, and I have personally seen high voltage current pass through items you would never dream could conduct electricity - including dry rope. Trace moisture is a wonderful conductor, and the typical distribution voltages of 4,000 to 14,000 volts found in back alleys and neighborhoods everywhere are enough to blow your hands off your arms and your body out of your boots. All that and kill you. too.

We wouldn't dream of entering a collapse-prone structure even though we might have three or four seconds of reaction time. Why take a risk on something with a reaction time of 1/60th of a second? Your first hint that you made a bad choice would be when you wondered where all the angels came from.

[Bowbreaker]

At a safety demonstration last fall a 7200 volt line was dropped on a tire sitting on a grounded metal plate. When the line hit the tire it blew a chunk of rubber out of the tread. I never would have guessed that rubber would conduct electricity but I saw it with my own eyes. Our only guess is the rubber has enough carbon in it and with the metal in the belts and bead, the tire will conduct electricity.

There is no way to tell how much current will pass thru a rope or what ever. Like I said before, you have to isolate the downed line so it doesn't contact anything and that's not possible. The only way to safely move a downed power line is to have a qualified person remove the power and ground the line no matter how long it takes.

Here a power company employee is the one that moves the line even after the power is removed. It is not unheard of to think the line was isolated and it wasn't. It isn't worth the risk.

We're lucky on our dept. Our chief, training officer, and 4 other firemen are power company employees. We have the power companies frequencies in our radios and they have ours. There is at least 1 lineman, usually not a fireman at daytime calls, and a bucket truck at every structure fire and any other time we request assistance. Some times they beat the fire trucks. Our power company is really good to the fire department and the community.

Brad

[ElectricHoser]

Why take a risk on something with a reaction time of 1/60th of a second?

After I went home I realized that my number above was in error. 60Hz AC power means 60 cycles per second. The sine wave cycle goes from nothing to a full pulse and back in 1/60th of a second. That means that if you happened to grab the line in that millisecond when the sine wave is at zero, you will have 1/120th of a second before you get to the top of the sine wave. Assuming this amazing perfect timing, you are still dead well before the 1/120th of a second it took you to get to the top of the sine wave.

The outcome is the same. Any questions?

[drcampbell]

At a safety demonstration last fall a 7200 volt line was dropped on a tire sitting on a grounded metal plate. When the line hit the tire it blew a chunk of rubber out of the tread. I never would have guessed that rubber would conduct electricity ...

This isn't surprising at all. There are thousands of different compositions of "rubber", each with different properties. On-highway tires are deliberately made of an electrically-conductive polymer to drain away static charge. (a nuisance when exiting a vehicle; an ignition hazard at a gasoline filling station) Radiator hoses are also conductive to prevent a voltage difference between the block and radiator, to minimize galvanic corrosion.

Even if a material doesn't conduct, a layer of grime, soot or moisture on its surface might. Absent that, there might be enough capacitance to either pass reactive current (biological tissue doesn't respond any differently) or initiate an arc through the air.

60-Hz power actually rises from zero to maximum in 1/240th of a second. Not that it changes the outcome any.