Bear Grylls Worst Case Scenario - Truth or Mis Truth?

If there's not enough potential to arc between the car metalwork and ground (across the few inches between say the wheelrims and the ground), there certainly wouldn't be enough to flash over to someone a couple of feet away.

There may be enough to jump the half-inch or so of a shoe sole - I wouldn't risk setting foot on the ground while in contact with the car, but I'd say a short jump away should do the trick.

Only reason I can see for the crawling (rapidly) away would be if there's a chance of a fuel explosion - or maybe to minimise the chance of the HT cable slipping off the car an contacting you - but on balance I'd say you'd have a better chance running.

Few things those surprise me.

How come telephone pole was having power cables? Or Are you calling telephone wires as power cables? If that is the case I cant digest if that can be a issue of safety until unless vehicle don't caches fire.

Second thing is when and where did it happen? Here in my country I don't see any active telephone poles for last 10 to 12years. as everything gone underground in fiber-optics.

May be there are toppings in the story.

This is television. It's pretend. Entertainment.

There are millions of wooden poles that support electrical power lines here in the USA.

Here's the bottom line. None of the advice given during the episode would cause more harm, if followed. But it made for good entertainment, right? How could the show have gone on if the "hero" just opened the door and jumped out?

I saw the show. It's hype.

Cheers.

Welcome to CR4.

so instead of staying in the car, he leaps from it, only his lace on his survival boot gets caught on the seat buckle and trips, making contact full contact between the car and the wet ground its on top of.

The producer is heard saying are we still rolling.....keep rolling, this is gold. The producer then begins to narrate the mishap for Bear.

it seems that Bears unfortunate accident he became the electrical conduit between the electrified car and the ground. As Bear is quivering and convulsing on the ground, Wait,.....I believe Bear just wet his pants making matters worst by adding to the contact with the his own urine which is dielectric.

Oh the humanity.

He's all alone on this desolate road, with no one in site......If you look close, Bear is starting to smoke.....

_{(can we do one where he slips on the boiling transformer oil spewed all over the roof?)}

His advice makes sense for higher voltage transmission lines (> 15 kV) and for lightning strikes. In these cases, rubber car tires and shoes are insufficient insulation and voltage potentials between your feet, from the dissipating ground currents, can be lethal.

For the standard telephone pole (more accurately called a utility pole), the voltages are usually less than 15 kV. All power utility lines carry lethal voltages and currents and any contact is VERY dangerous, as can be seen here:

http://www.youtube.com/watch?v=jR7guj9U2bM&feature=related

Bear's advice may be overly cautious, but it should cause no harm. Better safe than sorry dead.

Let me preface my post by saying that I'm not an engineer, so I'm completely out of my depth here. I only found this thread/forum because I also happened to be wondering about the accuracy of that episode. But, based on my extremely limited understanding of physics, if the rubber tires are insufficient to insulate the car from the ground (or if sheet-metal was grounding the vehicle), then wouldn't the occupants have been electrocuted (or at least severely shocked) the second the power line touched the car?

Also, just because something is television or entertainment, that doesn't mean it's necessarily 100% inaccurate; nor does it mean that one can't discuss the information presented in a documentary-style show. Yea, Discovery Channel's programming quality has really gone down in the past couple years, but they still have technical advisers and occasionally get things right. It's not like we're arguing over how the Deathstar was destroyed by a "proton torpedo" or how a lightsaber works. Even _if_ WCS were a TV drama, electricity is a very real physical phenomena, and there's nothing wrong with asking "how would this scenario really play out in real life?"

But I'm not one of those people who feels that you should just "turn off your brain" whenever you sit down in front of a TV. To me, the quality of a documentary show is reflected in how well they research their subject and the accuracy of their info. There's almost no point in watching a documentary series (instead of something like 24, Lost, etc.) if it's not reasonably true to reality.

Point well made. The occupants inside the vehicle will not have to worry about an electric shock from a voltage wire on the vehicle, regardless of the chassis being grounded or not. All of the occupants will be at the same potential voltage, so no electrocution can occur. The initial danger will be making the transition from the vehicle to ground if the vehicle is not grounded and the voltage cable is still live in contact with the car. This leads to the high drama scenario of leaving the vehicle with power still applied. This can be done by hopping off the vehicle so that at no time does a person touch both the ground and the electrified chassis simultaneously. This does not have to be a big leap, but just enough that a person does not complete the current path to ground. It's actually better that the leap be small and well controlled for precisely the next hidden reason. Ground itself is a poor conductor, so not all locations on the ground will be at the same potential. To prevent a person from electrocuting themselves on any step away from the downed wire, its a good idea to not stride or run away from the downed wire. Instead shuffle or slide your feet along the ground so that your feet are never far apart from each other.

As I mentioned in my other posting, I did not see this episode so I have no idea what Bear Grylls did. But in general the first response when anyone confronts an accident scene is to call for help. Getting emergency responders on the way to the scene is the first priority. After that, unless an imminent hazard exists that must be corrected it is better to stay with the injured and wait for people with the correct tools and knowledge to assist. Of course, if nobody can come then caution should still be your guide.

You're right. Many years ago (Christ! All my sentences start like that anymore) I was working for a utility company and we had a medium voltage tower up in PA go bad. It was steel, sitting on concrete but, for whatever reason, the concrete was a lousy conductor. So, the steel was up near 20 000 V (we thought) and a couple guys (no, not me) actually took running leaps and jumped onto the tower and climbed up far enough to pull a switch (This was one of the old style, big knife disconnects).

Ah, of course. Like I said, I'm completely out of my depth here. That makes sense though, and it explains redfred's statement.

Bear's statements made in the short clip below are reasonable.

http://dsc.discovery.com/videos/worst-case-scenario-downed-powerline.html

It is OK to question his advice and to learn why it may be good (or bad) advice. I think it is prudent to question anything you see on TV.

Now that I've seen this quick clip I agree that this is all reasonable advice after making a bad initial choice. I don't like that at no time did Bear Grylls attempt to call for help, but there was precisely this advice in the text introduction. What I dislike is the idea of getting into a vehicle with nobody else there just because there might be an imminent threat. This is like a confined space safety watch person running into the confined space before getting help. You are looking at a trap that has already trapped somebody. Going in alone on a reflex response makes the likelihood of being trapped, too. I also disliked the running urgency displayed, acting before thinking makes for more dead people.

While this is television hype, there are a variety of scenarios that are not well known in this that can make this a dangerous condition if one guesses wrong what is actually happening. I did not see this specific show so I have no idea how much was covered and what wasn't.

First, one should not assume that the vehicle is or is not electrically isolated from earth. This is an accident scene, sheet metal maybe embedded into the ground thus grounding the vehicle. The power wires may not be touching the car, they maybe resting in the cooling water that's leaking onto the ground. This latter scenario will mean that a voltage gradient can be distributed across the ground. By jumping, falling and catching yourself with the natural response of extending your arms out to brace the fall, your hands can conceivably land across a sufficiently large enough ground voltage gradient to deliver a shock directly to the heart.

My point is that one must make assumptions in this scenario that will then determine which path will be safer. But a wrong assumption can make the chosen path more dangerous.

Also, an unconscious person involved in an automobile accident should not be moved by an unqualified individual. Moving an unconscious person without an appropriate fracture analysis and/or supporting equipment to prevent further injury can compound the injuries. Bear Grylls was not playing the part of an EMT, Physician, or even a fireman. He was portraying a good Samaritan. Always call for qualified help first. Unless there is obvious imminent danger that a good Samaritan can mitigate, wait for help to arrive.

Good points about the various possible scenarios - but I maintain that there are few in which crawling away could lead to salvation.

A large potential gradient across the surface of the ground (assuming it could exist) would be best dealt with by a series of jumps or "loping strides" from one foot to another - only one foot touching ground at a time, or by shuffling along penguin-style (whilst making a rapid departure). Lying down and crawling would certainly not help!

_{No penguins were harmed in formulating this comment.}

I knew an oilfield Toolpusher(my boss) who only had one hand.

He lost the other one, when he reached down to see if the ground was HOT,,it was.The downed telephone pole wire was barely touching the top of his car.

A Good man.He knew drilling rigs.

Joe in Texas

It's a TV show. It is not a training exercise for first responders.

Yes, this is a TV show. This is a TV show that instead of giving the populace information that will minimize harm to viewers or which will grant viewers a better appreciation of what a first responder needs to grasp, this is a TV show that shows what should be done after doing it wrong. I guess they know their audience.

You are assuming that the populace is watching the show for information and not titillation.

Populace doesn't want to be informed, they want stimulation!

Cheers.

When I was surfing through the guide and saw ..

Worst Case Scenario! Bear caught in car under downed power line!

Worst Case Scenario! Bear rescues two boaters!

I think his name is misleading.

..shuffle your feet while you scoot away?

...he also pushed her car out of the way .. with his truck.. with the spare tire lashed onto his bumper as an insulator.. he also made a neck brace out of his jacket and moved the victim.. a lot was happening

but I never saw a bear..

odd show.. good tv? not 100% sure

It is correct in principal and complies with emergency services training.

The big jump he performs is a good example of "nearly going wrong".

The jump should only be big enough to bring you clear of the vehicles body work by say a foot or two. A jump like his risks over balance and putting your hands down, or falling backwards, even into the vehicle; All may bridge fatal voltage.

All actions should be poised and calculated.

The shuffling technique is exactly correct and important with 11kV and very for higher voltage.

A note on tyres. The carbon content becomes conductive at high voltage so the car is grounded via a resistance. If current flows for a significant time the tyres will catch fire.

On things aside; I would see if the window wound down first. I would turn off the ignition.

Of other interest on handling the injured; Had he not sat the victim upright - she would likely suffocate in a few minutes. This is quite a common occurrence with unconscious victims where onlookers are afraid to 'move them'.

This one may already be dead. With that in mind:

Above all else I would not go charging over to a car that had hit a pole - at night especially - without carefully looking at the state, disposition and type of the wires!

So what Bear should have done is call the Fire brigade first, while he was doing that hazard inspection.

And perhaps the other options available to save the victim from suffocation or the incineration risk he left hanging, may have filtered into his 'activist brain'.

(see "All actions..." - above)

But the shuffling is correct and the reasons accurate. The rest is "interpretation" by an idiot who may have died on approach - and no one would have known about either of them.

All of you have raised some valid and very worthwhile points. First of all, having spent a life time in the electrical utility business I'll get my pet peeve out of the way. It is what confuses the person from India - - it is a UTILITY POLE! Unfortunately the mentality is that if it is a pole it is a "telephone pole" but if it is a wire down it is an "electric wire". I've worked hundreds of calls that were cable TV drops or phone drops laying across a street or driveway. However; it is good that the public errs on the side of safety and calls the electric company to identify and remove such wires. On the subject of exiting the car, Bear is pretty much right. His jump is over-exaggerated for TV audiences but he is pretty much right on with his advice. BTW, I have three words for all of you that are thinking about RUBBER tires being insulators - - - STEEL BELTED RADIALS.

Now for the Vagabonds real life knowledge. In about 1975 or '76 a transmission line crew working for Georgia Power (USA) were doing maintenance work on an energized 115KV line out in the woods of Georgia. I can't remember if they were in the swampy south or the nice conductive, red-clay north of the State. The crew Supervisor was sitting in his parked pick-up truck approximately 130 feet from the two pole "H" structure talking with a Journeyman Lineman who was "tooled up" prior to climbing the wooden structure with his "spurs". The lineman had one hand on the body of the truck when some equipment on the pole made contact with the 115KV line. Due to the step potential of the ground and the position of the lineman by the pickup truck the lineman at the pickup truck was killed instantly. He was the ONLY PERSON at the site that received any kind of shock at all. As a job steward at that company I was tasked with reading the accident investigation report to the assembled workforce in my District. That has stuck with me for over 40 years as to how step potential kills.

One thing that Bear may not have said is that if the passengers in the car are OK and the car is not in danger of burning (you don't see or smell smoke, etc.) then switch the car off and stay in the vehicle until rescue personnel get you out. Have a safe day! I got a helicopter to catch.