A Bird’s Eye View of Electricity
We talk about it all the time: Stay away from power lines or you may get electrocuted. Well, how is it that when we drive down the road and see birds sitting on a wire, they are perfectly fine?
I ask this question when I’m giving safety demonstrations to 4th graders. The answers I get back have been very interesting; I think my favorite answer from a student so far was “because birds have hollow bones.” They generally do, but that’s not the reason.
So, how can birds sit on a wire that is not insulated with 7200 volts of electricity going through it?
The answer is that birds — and our bodies — are conductors, but they do not get electrocuted unless they make contact with an energized line and the ground, or something in a different “potential.” Electricity flows by the movement of electrons through conductors. For electrons to move, there must be what we call a “difference in electrical potential.” The electricity flowing through a single power line at any voltage will continue along the path of least resistance and right past birds on a wire — because there is no difference in electrical potential.
However, if a bird touches the ground while sitting on a wire or flaps its wings and touches another electric wire with a different voltage or phase, the bird will be electrocuted. This is because the bird’s body becomes a path for the electricity to reach either the ground (which has no voltage) or the wire with a different voltage or phase.
Lightning always wants to move toward the ground, and electricity does, too. Therefore, if you have a hot wire and touch it while standing on the ground, the electrons will go through your body to get to the ground. Your body would act as a conductor, and you would get electrocuted in the process.
That is why we must never touch or go near a downed line. If you see a downed power line, always stay clear and keep a distance of at least 30 yards. Be aware that the line could make contact with tree limbs, vehicles, puddles, fences or anything else that is a conductor. There is no way of knowing whether that downed power line is still live. We must always assume it is hot and treat it like it is. Don’t risk your life on a guess — the odds are not in your favor.
Operators of farm equipment or vehicles must also know what to do if their vehicle comes in contact with a power line. Stay on the equipment, warn others to stay away, and call 911. Do not get off the equipment until the utility crew says it is safe to do so.
If you are safe in your vehicle, stay in the vehicle. If it is on fire, or you are not safe and must exit the vehicle, please follow these steps:
- Open the door or exit and jump clear of the vehicle.
- Land with your feet together and make sure you do not touch the vehicle. Remember: If you touch the ground and the vehicle at the same time, electricity will travel through you to the ground, and you could get electrocuted.
- After you have jumped clear from the vehicle and landed with your feet together, start to shuffle so that the toe of one foot shuffles forward along the length of the other foot, ensuring that both feet are in constant contact and always touching the ground. Shuffling will keep you in the same potential if any current is going into the ground.
- Once you get away from the vehicle, never attempt to get back in or even touch the vehicle until the utility crew says it is safe.
Please follow these rules to stay safe around electricity.