electrocution

[Woody643]

I know that the rule states that if you are on a crane that has come into contact with a power-line , and on fire that you should jump from the cab. Is it possible to get out of the cab and walk to the outrigger and then jump?

 

[Birken Vogt]

You do not want to be in contact with the machine and with the ground at the same time. Jumping places you in midair so at no point are you bridging the gap with your legs. The trouble is the further you travel on the machine the more chances you are creating to bridge a gap between various parts of the machine that may be at different voltage potentials. As long as you are moving along parts solidly bolted or welded you should be fine but the outriggers riding on greased pins might be a different story. They might also be OK.

Using the outrigger is a better plan than burning, though.

I think the best thing to do is to get clear of the machine as soon as possible by jumping. The outrigger would be preferable to bridging the gap with your body.

 

[willie59]

It's just my humble opinion, but if I were in a crane that was in contact with high tension lines, and the rig were on fire, I wouldn't bother taking a stroll down the deck to an outrigger, I'm flat out bailing from the cab, even if it's gets me a broken leg. My thoughts...a broken leg is better than dead.

 

[Jumbo]

If at all possible, stay put in the seat and keep your hands where they are! Think of many concentric circles around the machine, each with a different resistance. If you jump, and fall forward, trying to catch yourself with your hand, you have just made the “best possible circuit” for the current. One foot near the machine and the hand past the next few “rings.” End result, you burn off your arm or foot, or burn up the circuits in your body that control the heart. NFPA 70 E training has some terrifying and repulsive videos caught of people trying to do what you are talking about. All result in death or dismemberment and severe burns. The old lessons are not valid anymore, besides, if your boom stays in contact with the power lines, they will burn in half usually, and shut down the circuit at the source. Damned hard to be patient though when the sparks are flying.

 

[lantraxco]

I remember being told exactly that years ago like Jumbo said, don't remember by who or why, but I was wrenching for an outfit with lots of excavators and a couple mobile cranes at the time. The machine you're in is essentially a "farraday cage" which in simple terms means the metal in it is conducting the electricity around you to ground. Fire is fire and it's a hell of a choice to stay and burn to death or try to climb out or jump and get lit up like lightning hit you, but if at all possible stay in the seat and wait until it looks like the sparks have quit at least. Most hi lines these days have auto breakers which will shut down, then after a delay pulse the line to see if it's clear and if there's no short to ground, reset automatically, so keep that in mind also. Like the linemen say, if it ain't grounded, it ain't cold.

 

[Nitelite]

A friend of mine lost his son in a work related accidental electrocution. Seems that he raised a fork lift to empty trash in the dumpster out back and contacted high voltage wires above. He was ok until his foot contacted the ground as he stepped down off of the machine. He was identified by his teeth.

 

[.RC.]

If you have to get off a machine that is in contact with lives wires you carefully jump in a way you can land with both feet together and stay upright, then you continue to jump feet together until well away from the machine...

Reason is the voltage radiates out from the machine falling to a lower voltage with distance, if you walk or fall over or whatever, some part of your body touching the ground might be at 1000V the other part on the ground might be 1500V, thus electricity will travel through you..

If you jump feet together you do not create a voltage difference for an electrical path to travel...

 

[kshansen]

.RC. That is just what I was told also. I hope to never have to try that, the urge to run like crazy would be hard to suppress.

 

[lantraxco]

Unless you are in immediate danger of being burned or blown up or crushed, close your eyes, pull your arms and legs up into a ball, and STAY inside the metal box. That is absolutely the safest place to be if the electricity is the only danger you're facing. Even if the power seems to go dead, wait for the fire or powerline crews. Some breakers will trip when they sense leakage to ground, BUT they will also in many cases try to automatically reset after a short time, they're designed like that clear tree branches and such that may contact the line.

 

[OCR]

If you have to get off a machine that is in contact with lives wires you carefully jump in a way you can land with both feet together and stay upright, then you continue to jump feet together until well away from the machine...

Reason is the voltage radiates out from the machine falling to a lower voltage with distance, if you walk or fall over or whatever, some part of your body touching the ground might be at 1000V the other part on the ground might be 1500V, thus electricity will travel through you..

If you jump feet together you do not create a voltage difference for an electrical path to travel...

:thumbsup...

http://en.wikipedia.org/wiki/Earth_potential_rise

http://en.wikipedia.org/wiki/Stray_voltage

Unless you are in immediate danger of being burned or blown up or crushed, close your eyes, pull your arms and legs up into a ball, and STAY inside the metal box. That is absolutely the safest place to be if the electricity is the only danger you're facing. Even if the power seems to go dead, wait for the fire or powerline crews. Some breakers will trip when they sense leakage to ground, BUT they will also in many cases try to automatically reset after a short time, they're designed like that clear tree branches and such that may contact the line.

:thumbsup...

http://en.wikipedia.org/wiki/Recloser




OCR


ps: Just cause it's interesting

 

[Queenslander]

Then,of course, if you are lucky enough to survive unscathed after a brush with power lines, you should be aware of the risk of tyres exploding for maybe 24 hours after the event.

 

[Garrie Denny]

Exactly Queenslander, possibly even longer, after the power contact the tyres CAN start to burn internally,unseen from outside until an almighty explosion of the tyre.

 

[OFF]

I've been on work sites where gravel trucks have contacted power lines with their boxes raised to dump. It's something to watch out for that we wouldn't normally think about as a hazard.

 

[kshansen]

I've been on work sites where gravel trucks have contacted power lines with their boxes raised to dump. It's something to watch out for that we wouldn't normally think about as a hazard.

Don't know about other areas but around here when road work like paving is being done they have someone walk the route and paint lines on the road under every overhead wire. Not saying the truck drives will see them all the time but it's an attempt.

 

[lantraxco]

I've been on work sites where gravel trucks have contacted power lines with their boxes raised to dump. It's something to watch out for that we wouldn't normally think about as a hazard.

Yeah, you reminded me of one job where the drivers were warned about the power lines and they had a laborer spotting as a precaution... one driver managed to ignore the spotter and got into the fireworks anyway... everybody hollering to stop, he slammed the throttle to the floor and managed to break the wire and drive clear... only got unemployed instead of dead, couple blown tires and a new dump cylinder for the truck. Luckily nobody else was under the wire when it came down. I think the truck went to the auction, heaven knows what it did to all the bearings in the axles, etc.

 

[Tones]

Unless you are in immediate danger of being burned or blown up or crushed, close your eyes, pull your arms and legs up into a ball, and STAY inside the metal box. That is absolutely the safest place to be if the electricity is the only danger you're facing. Even if the power seems to go dead, wait for the fire or powerline crews. Some breakers will trip when they sense leakage to ground, BUT they will also in many cases try to automatically reset after a short time, they're designed like that clear tree branches and such that may contact the line.

Just going on from that if someone is in the situation where they are injured and still in or on a machine with lines in contact with it LEAVE THEM THERE, NO RESCUE ATTEMPT SHOULD BE MADE until it's confirmed the lines are inactive usually by the power company.

 

[D11RCD]

Another good one to watch would be the electrical (not necessarily HV but still dangerous) wiring in the roof of workshops.

I would have jumped if the need arose until I read this thread... possibly should be made a sticky for novices like me?

 

[norite]

Here is what I would do if I contacted a power line.

1. If vehicle can still move, reverse or swing away from the power line until clear. If the line breaks and falls to the ground you are still in danger.

2. If not possible to break contact with the line stay in your seat until power co. tells you it is safe to get out. Power line circuit breakers often reset several times to burn off branches or trees that contact the line.

3. If machine is in contact with the line and fire makes staying put impossible, you must jump from the machine to the ground, make sure you are not touching both at the same time, keeping your feet together, you must not fall or roll on the ground.

4. Shuffle your feet, touching each other, no more than one half of your foot length at a time and move as directly away from the machine or power wire as possible. Keep this up, electrical potential can extend far from the point of contact. Shuffling your feet is recommended rather than hopping to reduce the risk of falling to the ground which could be fatal. Normal walking or running could be fatal, there may be a potential voltage of several hundred volts between your feet. Same principle as a cow getting killed when lightning strikes a tree 50 ft away, front legs and back legs are far enough apart that there could be enough voltage between them to cause electrocution.

5. Not just overhead power lines are dangerous, many high voltage power cables are buried and pose the same danger when excavating.

I recommend everyone research this and/or get training, you need to know what to do before it happens and possibly panic.

 

[92U 3406]

Been there, done that. It is a scary situation. Some unknown force was looking out for me that day. Look up and live. I take it to heart because I know that day could have easily been my last.

Unless there is an immediate threat to your life, DO NOT MOVE! Touching any part of the machine carries a risk of electric shock. If you absolutely have to bail, feet together and hop or shuffle until you are far away from line. As mentioned previously, voltage runs in concentric circles, with voltage becoming weaker the further away you get. Being in contact with 2 different voltages will cause YOU to become the short circuit.

 

[Willie B]

A knucklehead with log loader was working near a high tension power line in Bristol VT. He deliberately had a full length tree he was swinging close to the line to see if he could get an arc. He ended up collapsing the loader with tree resting on the line. The hydraulics melted disabling the loader. Ultimately setting fire to it. By the time power line crew arrived he was badly smoked up, but otherwise healthy still sitting in the operator's seat. He didn't dare climb, or jump.

I never did hear what his punishment was.

Willie