Why electricity kills

Zero voltage between two points is like a plateau and, hence, there is no current flow. An object's electrical resistance measured in ohms limits the amount of current that any voltage can drive through it. The stronger the resistance, the more voltage you need to push the same amount of current. The body's natural resistance is its defense against electricity.

Internal tissue has a low resistance compared to the skin. Thus, small shocks are not a problem, but once the skin is breached, the rest of the body is defenseless. That explains why a 3-volt battery is harmless, but Old Sparky was rather deadly. Dropping an electrical appliance into the bathtub can be lethal for precisely this reason. Thus, a volt hair dryer dropped in the bathtub can kill a person but grabbing the terminals of a volt car battery with dry hands produces no meaningful shock.

Another factor is the difference between alternating current AC and direct current DC. A constant voltage between two points can drive a current that does not fluctuate DC. However, a fluctuating voltage drives an alternating current AC , in which electrons are actually being spit out of an electrical outlet and then sucked back into it roughly 60 times per second. The fluctuation rate of 60 Hz makes these currents particularly suited to screwing up the nerves that regulate heartbeat.

This can cause a heart to flutter instead of beating normally, which kills a person quickly. That's why standard AC wall current is especially dangerous to humans. It would have little potential to really hurt you. But a large river with lots of water amperage can drown you even if the speed of flow voltage is relatively slow.

Of the two, amperage is what creates the greatest risk. Different amounts of amperage affect the human body in different ways. The following list explains some of the most common effects of electrical shock at various amperage levels, according to the U. To understand the amounts involved, a milliampere mA is one-thousandth of an ampere or amp.

A standard household circuit that supplies your outlets and switches carries 15 or 20 amps 15, or 20, mA. This gives you an idea of just how much danger there is in the home wiring system we take for granted, where wires carry 15, or 20, mA.

The best way to prevent electrical shock is to follow standard safety procedures for all electrical work. Here are some of the most important basic safety rules:. Zemaitis, Michael R. Electrical Injuries. Basic Electrical Safety. Actively scan device characteristics for identification. Use precise geolocation data. Advanced Search. Search Menu. Article Navigation. Close mobile search navigation Article Navigation.

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