Surge Current Protector and Surge Voltage Protector
Surge Current Protector is used for voltage limiting, which has 100KA, 60KA, 20KA, 5KA etc. It continuously limits hundreds thousands of lightning voltage to 3000V, 2000V, even 1000V below.
Standard requires 1000V Surge Protection for L-N wires and 2000V Surge Protection for L-GND, N-GND and L-N-GND, so manufacturers have to consider surge voltage protection 1000V of L-N and 2000V of -GND for their products.
Sometimes, some countries is not good for electric protection for management. We have to consider some Surge Voltage Projector like 10KV for products protection.