Apparatus safety in front of overvoltages coming from the power lines

The present paper deals with the problem of electronic and electrical apparatus protection against overvoltages coming from the power lines. This problem is particularly important for special structures far from another consumers. This work is executed in accordance with IEC 62305 and the source of damage S3 is considered. In contribution, the special focus is dedicated for the downstream SPD selection placed near the apparatus to be protected.