IEC 62305-4:2010(E) provides information for the design, installation, inspection, maintenance and testing of electrical and electronic system protection (LPM) 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oscillation and induction phenomena in the circuit downstream of SPD. 5) Annex C dealing with SPD coordination is withdrawn and referred back to SC 37A. 6) A new informative Annex D is introduced giving information on factors to be considered in the selection of SPDs.