Direct current voltage as low as how many volts has been known to cause fatalities?

• A. 30 V
• B. 42 V
• C. 60 V
• D. 120 V

Answer: (B)

Understanding how dangerous a voltage is depends on the current that can flow through the body, not just the number on the dial. The body’s impedance plays a big role, and conditions like wet or sweaty skin, cuts, or a path that goes through the chest can dramatically lower resistance and allow a dangerous current to pass through vital organs. In practice, fatalities have been reported with direct current at surprisingly low voltages, around 42 volts, when the conditions permit enough current to reach the heart or brain for a sustained moment. That’s why 42 volts is often cited as a hazardous DC level. The other higher voltages would also be dangerous, but the historical documentation of fatalities at about 42 V makes that value the best choice in this context. Always treat voltages in the tens of volts range as potentially dangerous in real-world work, especially in environments with moisture or conductive contaminants.