Let-Go Current is the maximum electrical current level at which a person can voluntarily release a conductor or an object carrying the current. If the current exceeds this value, the electrical stimulation causes involuntary muscle contractions, making it impossible to let go of the object.
Key Characteristics of Let-Go Current:
- Different for Men and Women: For men, the let-go current is approximately 9mA, for women, it is approximately 6mA.
- Below the let-go current a person may feel a tingling sensation but retains control over their muscles. At or above the let-go current: Muscles seize involuntarily, causing the individual to "grip" the conductor and be unable to release it.
- Dependence on Frequency - Alternating Current (AC), particularly at frequencies between 25–60 Hz, tends to have a stronger effect on muscle control than Direct Current (DC), making the let-go threshold more critical for AC.
- Relevance to Electrical Safety: Let-go current is a key consideration in designing safety protocols and equipment, as currents exceeding this threshold can result in prolonged exposure, increasing the risk of severe injury or death.
Practical Example of Let Go Current:
- If a person accidentally touches a live wire and the current flowing through their body is below the let-go threshold, they may pull their hand back instinctively. However, if the current exceeds the let-go current, their muscles will contract involuntarily, causing them to remain in contact with the wire, potentially leading to fatal consequences.
- This is why electrical safety equipment like insulated gloves and circuit breakers are essential when working with or near live electrical systems.
