How to Select a Proper Surge Protector?

Surge Protective Device is a device designed to protect against transient overvoltages, serving as an important component of the internal lightning protection system. According to its specific usage, there are mainly three types: power surge protective device, signal surge protective device, and antenna feeder surge protective device. Now let's explore how to select the right surge protective device from its various models.

(1) For the AC power supply line of building, at junctions of the main distribution box, e.g., LPZ0A or LPZ0B and LPZI, surge protective device of class Ⅰ or Ⅱ test shall be provided for first stage of protection; at junctions of subsequent LPZs including areas of distribution boxes for both distribution lines and electronic equipment, surge protective device of class Ⅱ or Ⅲ test may be provided for post-stage protection; for particularly important electronic information equipment power port, surge protective device of class Ⅱ or Ⅲ test may be installed for dedicated protection. Information equipment using DC power supply should, based on its working voltage required, be provided with surge protective device adaptative to the DC power supply line.

(2) The stage of quality signal surge protective device shall be so set as to take factors such as protection distance, length of surge protective device connecting wire and rated impulse withstand voltage UW of the equipment to be protected into comprehensive consideration. surge protective devices at all stages shall be able to withstand the expected discharge current at the mounting point and their effective protection level UP/F shall be less than the UW of the equipment of corresponding types.

(3) When the line length between voltage switching type surge protective device and limiting type surge protective device is less than 10 meters and that between limiting type surge protective devices is less than 5 meters, a decoupling shall be added between two stages of surge protective devices. When the surge protective devices have an autonomic function of energy matching, the line length between surge protective devices is unlimited. surge protective devices shall be provided with overcurrent protection and deterioration display function.

(4) For installing power surge protective device in different positions, the surge protective device connecting wire shall be straight and short and should not be longer than 0.5 meters in total length. The effective protection level shall be less than the rated impulse withstand voltage of the equipment.

(5) The length of the line between the locality of power surge protective device and protected equipment room shall be larger than 10 meters.

(6) When the length of the line between the power surge protective device at the entrance for first stage of protection and protected equipment is larger than the specified value, an additive surge protective device shall be installed at either the distribution box for distribution lines or the protected equipment. When multiple stages of quality surge protective devices are set on one line, their energy matching shall be taken into consideration.