How Electrical Current Affects the Human Body![]()
![Lightening Striking in a City]( "Lightening Striking in a City")
Three primary factors affect the severity of the shock a person receives
when he or she is a part of an electrical circuit:
when he or she is a part of an electrical circuit:
- Amount of current flowing through the body (measured in amperes).
- Path of the current through the body.
- Length of time the body is in the circuit.
Other factors that may affect the severity of the shock are:
- The voltage of the current.
- The presence of moisture in the environment.
- The phase of the heart cycle when the shock occurs.
- The general health of the person prior to the shock.
Effects can range from a barely perceptible tingle to severe burns and immediate cardiac arrest. Although it is not known the exact injuries that result from any given amperage, the following table demonstrates this general relationship for a 60-cycle, hand-to-foot shock of one second's duration:
| Current level (Milliamperes) | Probable Effect on Human Body |
| 1 mA | Perception level. Slight tingling sensation. Still dangerous under certain conditions. |
| 5mA | Slight shock felt; not painful but disturbing. Average individual can let go. However, strong involuntary reactions to shocks in this range may lead to injuries. |
| 6mA - 16mA | Painful shock, begin to lose muscular control. Commonly referred to as the freezing current or "let-go" range. |
| 17mA - 99mA | Extreme pain, respiratory arrest, severe muscular contractions. Individual cannot let go. Death is possible. |
| 100mA - 2000mA | Ventricular fibrillation (uneven, uncoordinated pumping of the heart.) Muscular contraction and nerve damage begins to occur. Death is likely. |
| > 2,000mA | Cardiac arrest, internal organ damage, and severe burns. Death is probable. |
References
- NIOSH [1998]. Worker Deaths by Electrocution; A Summary of NIOSH Surveillance and Investigative Findings. Ohio: US Health and Human Services.
- Greenwald EK [1991]. Electrical Hazards and Accidents - Their Cause and Prevention. New York: Van Nostrand Reinhold.
| If the extensor muscles are excited by the shock, the person may be thrown away from the circuit. Often, this can result in a fall from elevation that kills a victim even when electrocution does not. |
| Note that a difference of less than 100 milliamperes exists between a current that is barely perceptible and one that can kill. |