Electricity is such an integral part of modern life that we don’t even think about it. We use it for everything, from personal grooming to cleaning our carpets. But electricity is dangerous if not properly contained, and it causes over 350 fatalities each year. Here’s what you need to know about electrical safety.
How Electric Shock Happens
Electricity travels in closed circuits, normally through a conductor. As long as the electricity is contained within the intended circuit, it remains safe. But sometimes a person’s body mistakenly becomes part of the electric circuit, causing electric shock.
It can happen when a person’s body comes into contact with:
- both wires of an electric circuit
- one wire of an energized circuit and the ground
- a metal part that accidentally becomes energized due, for example, to a break in its insulation
- another ” conductor” that is carrying a current.
Effects of Electricity on the Body
An electric shock can result in anything from a slight tingling sensation to immediate cardiac arrest. The severity depends on the the amount of current flowing through the body, the current’s path through the body, the length of time the body remains in the circuit, and the current’s frequency.
- Below 1 milliampere: Generally not perceptible
- 1 milliampere: Faint tingle
- 5 milliamperes: Slight shock felt; not painful but disturbing. Average individual can let go. Strong involuntary reactions can lead to other injuries.
- 6–25 milliamperes (women): Painful shock, loss of muscular control
- 9–30 milliamperes (men): The freezing current or ” let-go” range. Individual cannot let go, but can be thrown away from the circuit if extensor muscles are stimulated.
- 50–150 milliamperes: Extreme pain, respiratory arrest, severe muscular contractions. Death is possible.
- 1,000–4,300 milliamperes: Rhythmic pumping action of the heart ceases. Muscular contraction and nerve damage occur; death likely.
- 10,000 milliamperes: Cardiac arrest, severe burns; death probable
The longer the exposure, the greater the risk of serious injury. Longer exposures at even relatively low voltages can be just as dangerous as short exposures at higher voltages. Low voltage does not mean low hazard.
A severe shock can cause considerably more damage than meets the eye. A victim may suffer internal hemorrhages and destruction of tissues, nerves, and muscles that aren’t readily visible. Electrical safety isn’t something to take lightly.
Learn more about electrical safety with our OSHA Electrical / NFPA 70E training.