How to choose in 4 easy steps the proper Surge Protective Devices (SPD) to protect your installation according to IEC/EN 61643 standard.
1) Note the characteristics of the power supply in order to find out the maximum working DC and AC voltage for each line. Select the SPDs providing: Uc > maximum working voltage of the line.
2) Select the SPD type and its maximum current depending on the effects it should withstand:
Current that can reach the SPD | Type of SPD |
Direct lightning current: | Type 1 |
Lightning secondary effects: | Type 2 |
Attenuated surges: | Type 3 |
3) Select the SPD residual voltage according to the equipment to be protected. For example, for power supply lines it is recommended:
Equipment to be protected | Residual voltage (1.2/50μs) |
Very robust equipment (large motors, air conditioning, …): | < 4kV |
Non-sensitive or internally protected equipment: | < 1,5kV |
Very sensitive or non-protected against electromagnetic disturbances equipment: | < 1kV |
4) Select the model of SPD according to the aforementioned parameters and to the type of installation, as follows: