What is the meaning of In, Imax, Un, Us.max, Up, Uc, Uchoe?

In is the rated discharge current, which is the current value that the surger can pass 20 times (8/20 microseconds) when it is not damaged.
Imax is the maximum discharge current, and the surger can only pass the current value once (8/20 microseconds). Imax is greater than In.
Un is the rated working voltage of the low-voltage power distribution network.
Us.max is the highest operating voltage of the low-voltage power distribution network.
Up indicates the voltage protection level of the surger (2.5-2-1.8-1.5-1.2-1KV), which corresponds to In. When Up is applied to the surge device, the surge device acts to make a large inrush current In pass quickly and then return to normal, thus playing a protective role.
Uc is the maximum continuous operating voltage, which can be added to both ends of the surge device without causing changes in the characteristics of the surge device and the maximum voltage to activate the protection element.
Uchoe is the impulse withstand voltage of electrical equipment. According to the regulations of IEC60364-4, the impulse withstand voltage of electrical equipment with 3-phase grid voltage of 230V/440V is divided into 4 categories: 1.5-2.5-4-6KV.