Leakage current

Leak current flows from the power input line to the ground. According to the Electrical Equipment Technical Standards, the leakage current must be 1mA or less. When the insulation resistance decreases due to faulty insulation at terminal sections or moisture in electrical and electronic devices, the leakage current increases. If the leakage current becomes large, it can not only cause equipment failure but also pose a risk of electric shock.
A ground fault circuit interrupter cuts off the circuit when this leakage current exceeds the specified value. Normally, it operates when the current exceeds 30mA, which is the threshold considered safe for the human body.