Abstract: In the electrical design, the selection of the electrical safety clear distance has important impact on the reliability of electrical operation and the safety of working personnel. In the file DL/T 5352—2006“Technical Code for Designing High Voltage Electrical Switchgear”, only the safety clear distances for several conventional voltage classes were given. When the designed voltage is changed, it is unable to select the safety clear distance from the technical code directly. According to the comparison of the domestic standard with the international standards, the relation between the minimum electrical clear distance and the minimum safety distance was discussed, and the computing method of electrical safety clear distance was obtained.

Key words: minimum safety clear distance, minimum electrical safety distance, statistical operation overvoltage, computing method