Okay, you’re alegedly very safe if in a car and lightning strikes it. But what if it stikes the sun roof? Could it go right through the glass?
Glass is an insulator. the arc probably could go through the glass, but why would it want to when there’s all that metal surrounding it?
Reading the question made me wonder what happens when lightning strikes an elevated train. I’m sure it happens – though L (el if you’re out East) lines are usually surrounded by buildings, there are places where elevated lines are the highest metal objects around.
I can’t imagine the result would be the same as with autos. Trains are connected to steel rails through steel wheels and axles (as opposed to rubber tires operating on an asphalt or concrete road). More to the point, elevated trains are directly connected to an electric supply that flows INTO the train, at 600 volts or more. Suddenly a major flow of electricity comes in the “wrong” direction.
So what happens? Obviously, the motors, etc., under the cars are isolated from the metal exterior of the cars, or one would get a shock just from touching the outside of the train. But how good is that isolation? And if there’s damage, does it happen to the train only or does the lightning pass into the third rail and damage the power distribution system too?
First, you’re never 100% safe from lightning in a car.
However, it is one of the safest places to be because it’s reasonably well insulated on the inside and a pretty good conductor on the outside.
To understand why lightning can’t strike through a sun roof, you need to understand the basic mechanics of lightning. Lightning occurs due to a build up of opposite charges in a cloud and the ground. Before the stroke (the damaging part of lightning) there are ‘leaders’ that extend from the cloud toward the Earth and from the Earth toward the cloud. There can be many of these leaders and the ones that represent the shortest path to ground will be the ones that meet first. When the leaders meet, then the stroke has a path to ground and we can get a lightning strike. When you’re in your car and it’s about to get hit by lightning, the leaders have already traveled up your wet tires to your wheels, then the axel, the frame, and finally the body of the car and beyond. The path that lightning is going to take has been predefined by the leaders at that point and that path cannot be through your glass sun roof.
You should avoid contact with metal in your car during a thunderstorm because you might inadvertently create an alternate, less resistive path to ground through your body. This would not be good…
By the way, you can feel the ionized air when a leader passes through your body. Of this I can attest from personal experience. I was nearly struck by lightning as a young boy. I was in a thunder storm, soaking wet, crossing a vacant parking lot (OK, so I wasn’t a very bright lad). All of a sudden, I felt a tingling and the hair on my arms, despite being wet, stood on end. I quickly dived to the ground and lightning struck a small tree about 20-30 feet away.
John,
Sorry, overlooked your question. Essentially, it’s the same story (assuming the outer hull of the rail car is conductive). Think of it like this - essentially the hull is a lightning rod. As long as you’re not in the electrical path between the lightning rod and the ground, you’re pretty safe.
Lightning is in a hurry and it doesn’t bother to take detours that have no chance of getting it to ground…