Configuration Of Surge Protector In Main Power Distribution Cabinet Of Building - Selection Is The Key

From the main distribution cabinet of the building to the outdoor lighting distribution box, if the main distribution cabinet in the building has been equipped with a first-level (or second-level) surge protector, should the surge protector configured for this outdoor distribution box be a first-level or a second-level one?

The above situation depends on whether the cable is overhead and buried, the shielding situation, and whether the distribution box is within the direct lightning protection range.

1. When the cable is led out to the lighting distribution box, the lighting box needs to be equipped with a first-level SPD (Iimp: 12.5kA, Up＜2.5kV, 10／350us), and a backup protector SCB is added to the front end of the SPD;

2. When the cable is led out to the lighting distribution box, and the lighting box is within the direct lightning protection range, the lighting box can be equipped with a second-level SPD (Imax: 40KA, Up＜1.8kV, 8／20us), and a backup protector SCB is added to the front end of the SPD; can Imax: 40KA be changed to In: 30KA

3. When the cable is buried and led out to the lighting distribution box through a pipe, the lighting box can be equipped with a second-level SPD (Imax: 40KA, Up＜1.8kV, 8／20us), and a backup protector SCB is added to the front end of the SPD.