What this part covers
IEC 62305-4 specifies requirements for design, installation, inspection, maintenance and testing of surge protection measures intended to reduce permanent failure of internal electrical/electronic systems caused by LEMP.
Why external LPS is not enough
A roof and down-conductor system does not by itself protect sensitive power, automation, data and control equipment from conducted or induced surges. Internal measures must be coordinated with the building services and system architecture.
Project information needed
Electrical SLD, service-entry details, earthing/bonding arrangement, sensitive equipment, cable routing, telecom/data interfaces, PV/DC circuits where applicable, and existing SPDs are needed for a meaningful SPM/SPD design.
2024 additions
IEC notes new informative material on current sharing, PV installations, system-level testing and induced voltages in SPD-protected installations.
Engineering Reference Table
| Protection layer | Typical review |
|---|---|
| Equipotential bonding | Metallic services and conductive parts. |
| SPD coordination | Power, control, telecom/data, PV/DC where applicable. |
| Cable routing / shielding | Reduce coupling and LEMP effects. |
| Inspection / maintenance | Verify continued effectiveness of protection measures. |
Project Implementation Checklist
For an actual project, record the applicable standard edition, risk-assessment assumptions, approved drawings, selected design method, calculation revision, component specification, inspection/testing requirements and final engineering approval.
Official Source
Use the official issuing body's publication for the controlled standard text and current status.