How much volt power can be deadly if the individual is well grounded?

• A. 60 volts
• B. 120 volts
• C. 240 volts
• D. 480 volts

Answer: (B)

Current through the body is what makes electricity dangerous, not the voltage alone. When a person is well grounded, the path to earth has low impedance, so more current can flow for a given voltage. The heart can be disrupted by relatively small currents—on the order of about 100 mA or more—so a voltage that can push that much current through a person under typical wet or damaged-skin conditions is potentially fatal. At 120 V AC, the body’s impedance in realistic contact scenarios can allow currents in that dangerous range, making 120 volts capable of delivering a lethal shock to a well-grounded person. Higher voltages like 240 or 480 volts increase the risk further, while lower voltage like 60 volts is less likely to be fatal under normal dry conditions. So the 120-volt level is the one most associated with potentially deadly shocks when someone is well grounded.