Is it necessary to do first-level lightning protection for the distribution box installed outdoors?

May 23, 2022

Is it necessary to do first-level lightning protection for the distribution box installed by Anxun Lightning Protection Company? Original article, source

In practical projects, many distribution boxes are installed outdoors. In view of this situation, should the lightning arrester be installed with a primary or secondary lightning arrester?

First of all, we need to clarify the role of the primary lightning arrester and the secondary lightning arrester. The test waveform of the primary lightning arrester in the T1 test is 10/350us, which simulates the waveform of direct lightning strike, so if the outdoor distribution box is an overhead line When the risk of direct lightning surge intrusion is introduced, a first-level lightning arrester should be selected. When there is no direct lightning surge intrusion, the secondary lightning arrester can be selected. In fact, the secondary lightning arrester 40~80KA lightning arrester can already play a good protective effect.
However, according to the national standard GB50057 lightning protection standard division, the outdoor distribution box belongs to the LPZO area and enters the LPZ1 area, and should be equipped with a first-level lightning protection device for the T1 test.

In addition to considering this item, it is also necessary to consider the relationship between the protection level of the surge protector and the withstand voltage level of the equipment. The protection level of the first-level surge protector is generally around 2000V. When the withstand voltage of the equipment is too low, a first-level surge protector may be installed. When the surge arrester invades, the equipment will still be damaged, and the secondary lightning protection can be selected from products with various protection levels, such as the single-phase 220V final-level lightning arrester AM20C275, the protection level is 1.2kV. Therefore, the actual withstand voltage level of the equipment should also be considered when selecting a model.

The price of secondary surge protector is generally lower than that of primary surge protector. If the cost is excluded, you can choose the first-level surge protector of Anxun B+D composite type. AM-L/N-BD has both a Advantages of primary and secondary lightning protection