IEC 62305-4:2010

Overview

IEC 62305-4:2010 - Protection against lightning: Part 4: Electrical and electronic systems within structures gives guidance for the design, installation, inspection, maintenance and testing of surge protective measures (SPM) to reduce the risk of permanent failures caused by lightning electromagnetic impulse (LEMP) inside buildings and structures. This second edition (2010) updates the 2006 edition and introduces technical changes such as isolating interfaces, revised bonding cross-sections, and improved criteria for surge protective device (SPD) selection.

Keywords: IEC 62305-4, lightning protection, LEMP, surge protection, SPDs, SPM, earthing, bonding, lightning protection zones (LPZ).

Key Topics

• Scope and objectives: Focus on preventing failures of electrical and electronic systems (D3 type damage) due to electromagnetic effects of lightning.
• Design of SPM: Principles for creating protection layers and mitigation measures for internal systems.
• Lightning Protection Zones (LPZ): Definition and implementation of LPZs to manage electromagnetic environments inside structures.
• Earthing and bonding: Requirements and best practices for earth-termination systems, bonding networks and bonding bars to limit potential differences. (Minimum cross-sections were updated in this edition.)
• Magnetic shielding & line routing: Methods to reduce induced currents and magnetic coupling to sensitive equipment.
• Coordinated SPD systems: Guidance on arranging SPDs to protect different parts of a distribution network and improved SPD selection that accounts for downstream oscillation and induction.
• Isolating interfaces: New provisions for interfaces that reduce conducted surges on lines entering the structure.
• SPM management: Inspection, maintenance, documentation and lifecycle management of protection measures.
• Annexes: Informative Annex A–D provide evaluation methods, retrofit guidance, SPD coordination references (Annex C referred to SC 37A), and new Annex D on SPD selection factors.

Applications

IEC 62305-4 is used to develop practical protection strategies for:

• Data centers and server rooms
• Industrial control and process plants
• Telecommunications and broadcast facilities
• Healthcare facilities (hospitals)
• Critical infrastructure and utilities The standard informs system design, installation contracts, acceptance testing and periodic inspection programs to reduce downtime and equipment loss from LEMP.

Who uses this standard

• Electrical and EMC engineers
• Lightning protection and earthing designers
• Facility and asset managers
• Installers and maintenance teams
• Safety and risk assessors
• Standards committees and certification bodies

Related Standards

• IEC 62305 series (Parts 1–3 cover general principles, risk management, and physical damage)
• IEC/SC 37A (SPD coordination guidance referenced by this edition)

For procurement or compliance, refer to the full IEC text of IEC 62305-4:2010 for normative details, diagrams and annexed evaluation methods.