The voltage a human can withstand varies widely depending on several factors such as skin condition (dry or wet), contact duration, and current flow. Generally:
- Voltages above 50 volts are potentially harmful and can drive a lethal current through the body, especially if the skin is wet or sweaty, which lowers resistance significantly
- Under dry skin conditions, the body's resistance is high (up to 100,000 ohms), meaning higher voltages (around 5000 volts) would be needed to deliver a fatal current of about 50 mA
- In wet or sweaty conditions, resistance drops to about 1000 ohms or less, so voltages as low as 50 volts can be fatal because they can drive dangerous currents through the body
- Safety standards often consider voltages below 36 volts as safe under dry conditions, with continuous contact safety voltages around 24 volts
- The critical factor for lethality is current, with currents above 50 mA considered lethal, and currents as low as 10 mA potentially causing fatal heart fibrillation if they pass through the heart
- High voltage (above 500 volts) greatly increases the risk of severe injury or death due to electric shock, but voltage alone is not the only determinant; current and path through the body are crucial
In summary, while the human body might physically withstand voltages up to several thousand volts under ideal dry conditions, voltages above 50 volts can be dangerous and potentially lethal, especially when skin is wet or contact duration is prolonged. The lethal effect depends primarily on the current flowing through the body rather than voltage alone. Safety guidelines typically recommend keeping exposure below 36 volts to avoid serious risk
