IEC 62305-4:2006

Gives information for the design, installation, inspection, maintenance and testing of an effective lighning protection system for information systems in or on a structure.

Deals with the requirements of Surge Protective Devices (SPDs) standardized by IEC 61643-1. These SPDs are installed according to the Lightning Protection Zones concept given by IEC 61312-1. First, starting from primary relevant threats, gives instructions for the determination of the stress for individual SPDs. For SPDs installed within a complex system, it is admissible to divide the system into simple basic arrangements, observing the rules described. When the values and directions of the partial lightining currents flowing within the system are known, the appropriate SPDs can be selected. Also deals with basic questions of the energy coordination of SPDs among each other and between SPDs and the threat at the respective place of installation are to be considered for effective coordination. The proof of the coordination of SPDs installed in a system, is described briefly.

Provides methods for the evaluation of the effectiveness of shielding measures against LEMP for structures with information equipment such as electronic systems in case of direct and nearby lightning strikes. In addition it provides rules for bonding measures inside structures and for earthing methods relating to LEMP.

IEC 62305-4:2010 provides information for the design, installation, inspection, maintenance and testing of electrical and electronic system protection (SPM) to reduce the risk of permanent failures due to lightning electromagnetic impulse (LEMP) within a structure. This second edition cancels and replaces the first edition, published in 2006, and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: 1) Isolating interfaces capable of reducing conducted surges on lines entering the structure are introduced. 2) Minimum cross-sections for bonding components are slightly modified. 3) First negative impulse current is introduced for calculation purposes as electromagnetic source of harm to the internal systems. 4) Selection of SPD with regard to voltage protection level is improved to take into account oscillation and induction phenomena in the circuit downstream of SPD. 5) Annex C dealing with SPD coordination is withdrawn and referred back to SC 37A. 6) A new informative Annex D is introduced giving information on factors to be considered in the selection of SPDs. This bilingual version (2012-06) corresponds to the monolingual English version, published in 2010-12.