LDY-50A are applied to equipotential bonding of the low voltage side of transformer or main low voltage distribution boxes inside the building, providing protection against the overvoltage arising from the lightning strike to power supply system of class I or faulty operation,but they are not applied to the system of the expected short-circuit current beyond rated breaking afterflow current.

The series fuse must be at the front-end of the product, otherwise, the surge protector may be burned out by the developed power flow current, while the product is discharging.(option from standard IEC61643-1 and GB50343)

The two electrodes are connected to the line L (or line N) and line PE respectively. An electric gap is formed between the two lectrodes. The high-impedance state exists between the two electrodes when the electric network runs under the striking voltage. If the voltage between the two electrodes surpasses the striking voltage arising from the lightning or faulty operation on the electric network, arc through the electric gap and power energy releases through arc discharge. The arc will be extinguished by the arc quenching system consisting of detached arc slices and arc quenching room and the electric gap resumes to high-impedance state.The discharge gap is totally-enclosed and No arc escape.