Electric power does a tremendous amount of work. But because it’s such a powerful force, we need to be very careful with it. Approximately 300 people are killed and over 4,000 injured every year by electricity in the workplace. The reasons are almost always carelessness, a faulty appliance or tool, or a lack of knowledge about how electricity works. You can reduce electrical injuries and death by doing three things:
- Understanding how electricity works
- Recognizing potential electrical hazards
- Learning about safety devices that prevent shock.
Electricity naturally flows to the earth, or to ground, through anything that will conduct electrical current. There are some compounds, like wood and glass, that are not good conductors of electricity.
But electricity will pass through the human body, sometimes with fatal results, trying to get to ground. If an appliance or tool is faulty or has a shorted wire, for example, the electric current may try to find another path to ground. That’s why electrical systems should always be grounded. A safe path to ground for electricity is away from your body and confined within whatever piece of electrical equipment you’re using.
An electric shock is a reflex response to an electric current that enters the body. It is often painful and can be lethal. The severity of injury does not depend on the level of voltage that produces the shock. A small shock from static electricity may contain thousands of volts with very little current. On the other hand, extremely low voltage with an extended current duration can be fatal.
There are several effects of a shock from electricity. Extensive burns can occur from high-voltage shocks with strong currents. Around 500 to 1,000 volts may cause internal burns, and damage occurs through tissue heating in the body. Ventricular fibrillation may occur when a low voltage (110 to 220 volts) travels through the chest for a fraction of a second. If the current travels directly to the heart, an even lower voltage level can induce fibrillation, which is typically lethal because it stops the heart.