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: