Low voltage - 600 Volts or Less
The list below summarizes what usually happens for a range of currents with a duration of one second at typical household voltages of 600 volts or less.
Longer exposure times increase the danger to the shock victim. For example, a current of 100 mA applied for 3 seconds is as dangerous as a current of 900 milliamps (mA) applied for a fraction of a second (0.03 seconds).
Higher voltages will cause more severe burns. Differences in muscle and fat content affect the severity of shock.
- 1 mA: Just a faint tingle.
- 5 mA: Slight shock felt. Disturbing, but not painful. Most people can "let go." However, strong involuntary movements can cause injuries.
- 6-25 mA (women) and 9-30 mA (men): Painful shock. Muscular control is lost. This is the range where "freezing currents" start. It may not be possible to "let go".
- 50-150 mA: Extremely painful shock, respiratory arrest (breathing stops), severe muscle contractions. Flexor muscles may cause holding on; extensor muscles may cause intense pushing away. Heart fibrillation possible. Death is possible.
- 1-4.3 amps: Rhythmic pumping action of the heart ceases. Muscular contraction and nerve damage occur; death likely.
- 10 amps: Cardiac arrest and severe burns occur. Death is probable.
- 15 amps: Lowest overcurrent at which a typical fuse or circuit breaker opens a circuit! This means if you short out a 15 amp circuit, you could die.
Knowledge Check Choose the best answer for the question.
2-2. Cardiac arrest, severe burns, and death is probable if a worker receives an electrical shock of _____.
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