Installation Location Of Primary And Secondary Surge Protectors

Surge protectors, also known as lightning arresters, are suitable for AC 50/60HZ, rated voltage 220V to 380V power supply systems to protect against indirect lightning and direct lightning effects or other transient overvoltage surges. They are suitable for surge protection requirements in residential homes, the tertiary industry, and industrial fields. According to the different levels of protection power supply, they can be divided into primary surge protectors and secondary power surge protectors.

What is the difference between the installation of primary and secondary surge protective device? How to select them?

For AC power supply lines entering buildings, at the junction of LPZ0A or LPZ0B and LPZ1 areas such as the main distribution box of the line, a surge protector of Class I test or a surge protector of Class II test should be installed as the first-level protection; at the junction of subsequent protection areas such as distribution boxes of distribution lines and distribution boxes of electronic equipment rooms, surge protectors of Class II or Class III test can be installed as post-stage protection; special important electronic information equipment power ports can be installed with surge protectors of Class II or Class III test as fine protection.

(1) A surge protection device of Class I test should be installed at the main distribution box where the power supply is introduced. The voltage protection level value (Up) of the surge protector should be less than or equal to 2.5kV. When the impulse current value of each protection mode cannot be determined, the impulse current (Iimp) should be equal to or greater than 12.5kV.

(2) When there is a line leading out of the building to other distribution devices with independent grounding devices, a surge protector of Class I test should be installed on the busbar. The impulse current value of each protection mode of the surge protector should be equal to or greater than 12.5kA when it cannot be determined; when there is no line leading out of the building, a surge protector of Class II test should be installed on the busbar. The nominal discharge current value of each protection mode of the surge protector should be equal to or greater than 5kA. The voltage protection level value of the surge protector should be less than or equal to 2.5kV.

(3) A surge protector of Class II test should be installed on the power supply side of the switch in the distribution box. Its voltage protection level should not be greater than 2.5kV, and the nominal discharge current value should be determined according to the specific situation.

(4) When a surge protector is required to be installed near the equipment to be protected, that is, at the interface between the LPZ2 zone and the higher zone, a surge protector of Class II or Class III test should be selected for the electrical system.

According to the standard, different levels of surge protectors need to be selected in different application scenarios to achieve effective protection.