IEC 62305-4:2010 Protection against lightning - Part 4: Electrical and electronic systems within structures

International Standard IEC 62305-4 has been prepared by IEC technical committee 81:
Lightning protection.
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5) Annex C dealing with SPD coordination is withdrawn and referred back to SC 37A.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.