Creepage detection circuit

The invention provides a creepage detection circuit. The creepage detection circuit comprises a rectifying branch circuit, a capacitor, a bidirectional thyristor and an alarm module, wherein the rectifying branch circuit is electrically coupled to an equipment casing and consists of a resistor and a diode which are serially connected with each other; one electrode of the capacitor is electrically coupled to the rectifying branch circuit, and the other electrode of the capacitor is electrically coupled to the zero line end of a power socket; the bidirectional thyristor is electrically coupled to the capacitor; and the alarm module is electrically coupled to the capacitor and the bidirectional thyristor. When the equipment casing has a creepage phenomenon, the capacitor executes circulating operation of charging, discharging and recharging; and when voltage at the two ends of the capacitor is more than or equal to starting voltage of the bidirectional thyristor, the bidirectional thyristor is switched on and the alarm module outputs an alarm signal. After adoption of the creepage detection circuit, when the equipment casing has the creepage phenomenon, creepage voltage charges the capacitor, and when the voltage at the two ends of the capacitor is more than or equal to the starting voltage of the bidirectional thyristor, the bidirectional thyristor is switched on and the alarm module outputs the alarm signal, so that an operator is protected from personal injury caused by creepage of the casing.