Deadly Detroit Crash Is A Reminder To Stay Inside Your Car If You Hit Downed Power Lines

Illustration for article titled Deadly Detroit Crash Is A Reminder To Stay Inside Your Car If You Hit Downed Power Lines
Screenshot: WDIV Local 4

In the event of a car accident involving downed power lines, one thing you should take caution never to do is touch any surrounding wires. Unfortunately, a woman in Detroit reportedly died Monday morning after driving into a utility pole, then somehow coming into contact with a live cable.

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A video from Detroit news affiliate WDIV Local 4 shows the scene of the accident, near the intersection of Southfield Freeway and Tireman Avenue. An eyewitness reportedly saw the woman touch the wire and then start shaking, though how she touched it — whether by purposefully attempting to remove it or by nudging or stepping on it — isn’t fully clear. The article reports that she “grabbed” the line, though this isn’t attributed to authorities.

It’s difficult to tell from the perspective of the footage, but it appears the downed line may have been resting on the hood of her Chrysler 200. The woman was pronounced dead at the scene, according to Detroit police. That’s all the information we have at the moment; if there are any developments, we’ll update this story.

If there are downed power lines near your vehicle and there’s no fire or any imminent danger that requires you to leave, the best advice is to stay inside your car and call for help, according to Pacific Gas & Electric. Assume all wires are power lines, and warn any bystanders from approaching your car with your horn or, if possible, by lowering your window. Never try to leave the car if you don’t have to, as the ground surrounding it may be electrified, and remain in your vehicle until first responders arrive and deem it safe to exit.

Conversely, if you are in an emergency and do need to leave your car as quickly as possible, start by opening the door while taking care not to touch any bare metal. Try to hop out in a manner where your body and clothing clears the vehicle, and plan to land on both feet simultaneously. Then, shuffle away from the scene without picking up your feet.

Staff Writer at Jalopnik. 2017 Fiesta ST. Wishes NASCAR was more like Daytona USA.

DISCUSSION

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Not sure about not picking up the feet, but the danger is this. In high voltage cases, 5000-10,000V, at some distance from the contact point the ground will be at, literally, ground potential (0V) In between that spot and the place where the wire is touching the voltage is dropping off.

If both feet are at the same distance from the contact point they will be at the same voltage, which means no current will flow through you.

If you move one foot ahead of the other that will change.

Suppose the distance is 10 feet and the line is 5000V, that is 500Volts per linear foot. If the insulation in your shoes is not better than that, you can become part of the circuit. Take a 2 foot long stride and that’s 1000 V drop between one foot and the other - getting much closer to breakdown of the shoe insulation. And it’s not just the sole of the shoe to consider - any salty sweat that has gotten to the outside of the shoe along with some dirt on the side of the sole can create a path around the side of the sole.

Fall down, and that could be 3000V between outstretched hands and knees.

So, keeping the feet together*, possibly in bunny hops, pointed directly away from the place the wire is touching the ground is the way to go. I think the distance I’ve seen line workers keep people back is at least 50 feet, so in the 30-50 foot minimum range for residential wires.

Or better yet - wait for the power company to disconnect the power and tell you they have done so.

As far as bare metal in the car? A similar condition - but most problematic if the car is at 5000V and the ground is at 0V. Getting out then is tricky. Breakdown voltage of air is around 3000 V/mm, so if you get close to metal it can spark across and complete the circuit through you. So the technique is not to touch the car and the ground at the same time.

As workers on very high voltage lines and Telsa coil demonstrations show - if you are not part of a circuit you can be safe, but knowing you are not part of a circuit after a power line falls? That’s worth waiting for the power guys if you can.

*the breakdown path could be anywhere on the shoe, so if you have long feet, that’s a shame as it could find a path on the toes on one foot and the heel on the other.