Product selection guide for surge protectors

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: