GB 16895.12-2001

Electrical installations of buildings-Part 4: Protection for safety-Chapter 44: Protection against overvoltages-Section 443: Protection against overvoltages of atmospheric origin or due to switching (TEXT OF DOCUMENT IS IN CHINESE)

This standard establishes Part 4 of the standard "Electrical Installations of Buildings": Protection against transient overvoltages of atmospheric origin induced by power supply and distribution systems as well as protection against overvoltages due to switching caused by equipment within electrical installations.

The following aspects should be considered: overvoltages which may take place at power incoming port of electrical installations; local expected lightning strike level; location and characters of devices for protection against overvoltages. The purpose of taking the above into consideration is to lower the possibility of causing accidents by overvoltages to the permitted level for the safety of personnel and property as well as for uninterrupted power supply of equipment.

The value of transient overvoltages depends on the types of power supply and distribution systems (underground or overhead), the possibility of having low-voltage protection devices at power side of power incoming port of electrical installations and voltage withstand level of power supply and distribution systems.

This standard provides guidance to two kinds of protection measures against overvoltages, including self suppression (depending on insulation level of the systems themselves) or protective suppression (depending on installing electrical appliances for protection against overvoltages). If protection against overvoltages is not provided according to the requirements in this standard, insulation coordination cannot be ensured. Therefore, risk evaluation of overvoltages should be made.