What current level is typically fatal?

What current level is typically fatal?

• A. 1 mA
• B. 10 mA
• C. 100 mA
• D. 1000 mA

Answer: (C)

Current through the chest can disrupt the heart’s electrical rhythm. The heart coordinates each beat with precise electrical signals, and when a sufficient amount of current passes through, especially alternating current, it can push the heart into ventricular fibrillation—an uncoordinated, ineffective rhythm that stops proper blood circulation. This is why a level around 100 milliamps is commonly cited as a threshold where fatal outcomes become likely for a typical exposure. Smaller amounts of current are less dangerous: about 1 milliamp is usually just barely perceptible, and around 10 milliamps can cause a painful shock but not typically fatal. Much higher currents, such as one ampere, are also extremely dangerous and can cause severe injury or death, but the scenario most often associated with a fatal outcome in brief exposures is near 100 milliamps through the chest.

Current through the chest can disrupt the heart’s electrical rhythm. The heart coordinates each beat with precise electrical signals, and when a sufficient amount of current passes through, especially alternating current, it can push the heart into ventricular fibrillation—an uncoordinated, ineffective rhythm that stops proper blood circulation. This is why a level around 100 milliamps is commonly cited as a threshold where fatal outcomes become likely for a typical exposure.

Smaller amounts of current are less dangerous: about 1 milliamp is usually just barely perceptible, and around 10 milliamps can cause a painful shock but not typically fatal. Much higher currents, such as one ampere, are also extremely dangerous and can cause severe injury or death, but the scenario most often associated with a fatal outcome in brief exposures is near 100 milliamps through the chest.