IEC 61936-1:2021 standard is the primary international guideline for the design and erection of high-voltage (HV) power installations exceeding 1 kV AC and 1.5 kV DC
. Released in July 2021, this third edition provides critical requirements to ensure the safety of people and livestock while maintaining the proper functioning of electrical systems. BSI Knowledge Core Scope and Application Voltage Range:
Applies to AC systems above 1,000V and frequencies up to 60 Hz. Key Environments:
Covers power stations, substations, outdoor switchgear, industrial electrical systems, offshore generation, and transition towers/poles. Exclusions:
Does not apply to overhead/underground lines between separate installations, electrified railways, mining equipment, or medical X-ray equipment. IEC Webstore Significant Technical Changes (2021 Update)
The 2021 revision introduced several improvements to modernize safety protocols and clarify technical requirements: Insulation Coordination: iec 6193612021 link
Clause 5 was updated with improved wording and coordination with the latest versions of other insulation coordination standards. Safety and Labelling:
New requirements for labeling were added for situations where multiple power sources must be disconnected to ensure safety. Gas-Insulated Switchgear (GIS):
Missing requirements for GIS were reintroduced to reflect current technology. Electromagnetic Compatibility (EMC):
The standard now offers clearer requirements for EMC to mitigate interference in control systems. Safe Working Procedures:
Annex F was added as an informative guideline for safe working procedures in jurisdictions that lack local regulations. Infrastructure Improvements: Safety and Labelling: New requirements for labeling were
Enhanced requirements for transformer installations, ventilation (HVAC) subclauses, and updated figures in Clause 7. IEC Webstore Who Uses This Standard? Designers and Engineers:
For substation layout and power plant insulation coordination. Utilities and Grid Operators:
To ensure new installations and upgrades meet safety compliance. Contractors and Consultants: For erection, commissioning, and site supervision. Safety Managers: To verify compliance and conduct risk assessments. iTeh Standards Accessing the Standard
Official copies and detailed summaries are available through several international and national standards bodies: IEC Webstore The primary source for the international standard. BSI Knowledge Provides the BS EN IEC 61936-1:2021 version used in the UK. iTeh Standards
Offers a comprehensive overview of the standard's requirements and applications. safety clearance and site supervision.
As renewable energy plants (Solar PV, Wind) typically connect at medium to high voltages, IEC 61936-1:2021 serves as the governing standard for the on-site substations. The shift towards higher voltage DC collection systems (HVDC) is acknowledged, though the primary focus remains on AC installations. Engineers designing grid-interconnection points must strictly adhere to these guidelines to satisfy grid operators.
No. The 2021 date only applies to Amendment 1. The core document remains the 2017 edition. You must buy the “Consolidated version” (CSV) which includes the amendment.
Control cables must be physically separated from power cables by a minimum of 0.3 meters or a metallic partition to prevent induced voltages.
All high-voltage enclosures must have a warning sign reading: “DANGER – HIGH VOLTAGE – KEEP OUT” in the local language plus the standard lightning bolt symbol.
❌ Using 2010 clearances for systems with arresters – 2021 reduces some gaps.
❌ Ignoring Annex B for soil resistivity modeling – leads to unsafe touch voltages.
❌ Applying AC rules to DC installations – that is IEC 61936-2.
❌ Overlooking fire separation between control buildings and HV equipment – clause 9.3 is strict.