A review of IEC 62305–4 protection against lightning part 4: Electrical and electronic systems within structures

The IEC 62305 Ed 2 Protection Against Lightning series of documents was published as an International Standard in December 2010. The series comprises four parts. Part 4 deals with “protection of the electrical and electronic systems within the structure”. This new 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 a potential electromagnetic source of damage to internal systems. 4) Selection of SPDs with regard to their voltage protection level is improved to take into account oscillation and induction phenomena in the circuit downstream of the SPD. 5) The former Annex C dealing with SPD coordination, is withdrawn and referred back to the IEC SC 37A WG3 committee for development under their jurisdiction. 6) A new informative Annex D is introduced giving information on “factors to be considered in the selection of SPDs”.