If a broken powerline touches the metal body of my car, can I touch any metal parts of my car while sitting inside of it?

Question

Consider the following situation. I parked my car underneath some high-voltage lines – let’s say 380 kV-lines. Suddenly, one of the lines breaks in the middle due to a storm and one end of the (still energized) line now touches the metal body of my car.

Now I know that it’s obviously best to stay in the car unless it’s absolutely necessary to get out. I’m also aware of touch and step potential. The thing that I’m interested in is this: If I’m still sitting in my car and not touching any part of the ground outside, will I get shocked if I touch any metal part of my car?

Some sources that I checked claim that one cannot touch any metal parts of the car, while other videos that I’ve seen on youtube clearly show how the instructors touch metal parts of their vehicle before hopping out. For instance I remember an educational video where an instructor walks down the metal steps of his truck before jumping out.

My reasoning (I’m not a physicist/scientist by the way) goes like this: The metal frame of the car should be a very good conductor. So as soon as the car is contacted by the powerline, current will flow through the chassis, through the tires to ground. Now since the metal body of the car is a good conductor, all parts of it should roughly be at the same potential (ideally the potential difference between any two points on the car should be zero, much like in an ideal circuit where there are no voltage drops along the wire). So since all parts of the metal body are at the same potential, I should be good if I touch anything (again, while sitting completely inside the car and without touching the ground outside). I’m not sure if this reasoning is correct though. Could anyone explore this scenario more in-depth?

I guess another way to view this would be the following: If current flows through the car to ground and I’m touching, say, the ceiling and floor of the car simultaneously, there is now a network of parallel resistors through which current can flow. Since my resistance should be >> resistance of the car, no current (at least no lethal or harmful current) should pass through me. But again, I’m not sure if this reasoning is waterproof.

On a side note: If there are several passengers sitting in my car and one of them were to get out while touching both the car and the ground, would only this person get electrocuted or could this also electrocute everyone else sitting inside the vehicle?

Sorry, I guess I asked two questions now. But I’m kind of fascinated and intrigued by this whole topic.

PS: I also asked this question on physics.stackexchange.com, but I didn't get any answers there. I thought this forum might be more appropriate for the question.

Answer 1

The reality is that a 380 kV power line will find a path to earth across the surfaces of your tyres and, in all likelihood melt the types in a second or two thus causing your vehicle to collapse to the earth. You will then have bare metal touching earth and the current flow will be enough to melt the metal of your vehicle and kill everyone inside.

Your fuel tank will almost certainly rupture and the fuel will explode.

If there are several passengers sitting in my car and one of them were to get out while touching both the car and the ground, would only this person get electrocuted or could this also electrocute everyone else sitting inside the vehicle?

I doubt that there would be enough time to do this.

Answer 2

I think you underestimate the weight of a cable: if one end "touches" your car, more likely than not you have a structural integrity problem with your car. "Current will flow ... through the tires": significant current through the tires would burst them. After a high voltage line breaks, it will likely get switched off within a short time span. It may remain dangerous since it might brush other lines that are still operative.

The expectation would be that as long as you stay in the car, you'll be in a Faraday cage protecting you. After all, that works for lightning bolts. If the cable mainly touches the radio antenna (after all, most of the car's outer metal is painted over), you may have a dashboard problem.

Generally, most information concerning lightning strike will apply to some degree though lightning is momentary, comes with a hot plasma channel and quite higher voltages. The current is "just" an order of magnitude larger than what a high voltage line might nominally run at.