What is the let-go threshold on a 60-hertz AC circuit in milli-amperes?

The let-go threshold refers to the amount of electrical current that can pass through the body before a person is unable to voluntarily let go of an electrical conductor. In a 60-hertz AC circuit, this threshold typically ranges between 10 to 40 milli-amperes (mA).

At current levels below 10 mA, most individuals can maintain their grip on an electric conductor, while current levels in the range of 10 to 40 mA can induce muscle contractions severe enough to prevent a person from releasing their grip, leading to the risk of prolonged exposure to the electrical source. Above 40 mA, the potential for serious injury or fatality significantly increases as the associated physiological effects can include fibrillation or other critical reactions.

Understanding this threshold is vital for electrical safety practices, as it helps inform procedures to minimize the risk of injury when working with or around electrical equipment. Proper training emphasizes recognizing these ranges and adhering to safety protocols to prevent accidental contact with electrical circuits.