IEC 61936-1-2021 PDF

Full title and description

IEC 61936-1:2021 — Power installations exceeding 1 kV AC and 1,5 kV DC — Part 1: AC. This international standard gives requirements for the design and erection of electrical power installations with nominal voltages exceeding 1 kV AC (up to 60 Hz) to ensure safety and correct functioning for the intended use, including substations, switchgear, transformers and associated auxiliary systems.

Abstract

IEC 61936-1:2021 sets out common rules, safety measures and design requirements for high‑voltage AC power installations (nominal voltages > 1 kV AC). It covers fundamental design principles, clearances, insulation levels, equipment layout, earthing systems, protection and automation, electromagnetic compatibility, inspection and testing, and documentation required for safe operation and maintenance. The standard also lists specific exclusions (for example certain overhead/underground line interconnections, railway rolling stock, and marine/offshore installations covered by other IEC series).

General information

• Status: Current international standard (widely adopted as EN/BS/UNE national adoptions and with recent European amendment activity).
• Publication date: 2021 (published in national/adopted forms in Sept–Oct 2021; national publishers list dates such as 8 Sep 2021 and 1 Oct 2021).
• Publisher: International Electrotechnical Commission (IEC). National/adopted publications are available from CENELEC members and national bodies (BSI, AENOR, etc.).
• ICS / categories: 29.020 (Electrical engineering in general); 29.080.01 (Electrical insulation in general); 29.240.20 / 29.240.01 (Power transmission and distribution / networks).
• Edition / version: Edition 2021 (IEC 61936-1:2021).
• Number of pages: National/adopted versions typically list between about 126 and 130 pages (example counts: 126 pages in BSI listing; 130 pages in some national listings).

Scope

IEC 61936-1:2021 applies to the design and erection of electrical power installations in systems with nominal voltages exceeding 1 kV AC and nominal frequency up to and including 60 Hz, including substations, power stations on a single site, outdoor switchgear and transformers located outside a closed operating area, industrial and commercial power installations, and certain offshore installations. The standard does not apply to standalone overhead/underground lines between separate installations, railway rolling stock and electrified track systems, mining installations, fluorescent lamp installations, or ships/offshore units covered by IEC 60092 and IEC 61892 (those subjects are addressed by the relevant series instead).

Key topics and requirements

• Fundamental safety and design principles for high‑voltage AC installations (layout, segregation, access and safe working provisions).
• Minimum clearances, insulation coordination and rated insulation levels for equipment and system components.
• Earthing (grounding) system design, touch‑voltage and step‑voltage criteria and testing/maintenance requirements.
• Protection, automation and auxiliary systems — selection, coordination and basic EMC considerations.
• Cable and busbar installation rules, switchgear and transformer installation guidance, and mechanical/supporting structure considerations.
• Inspection, testing, commissioning, and operation & maintenance documentation (including required manuals and verification tests).
• Informative annexes providing example values (rated insulation levels, minimum clearances) and design flow aids; national annexes/notes may be added in adopted EN versions.

Typical use and users

This standard is used by electrical engineers, substation designers, installation contractors, utility planners, asset owners, safety & compliance teams, testing/commissioning engineers, and regulatory authorities involved in the design, erection, verification and maintenance of high‑voltage AC power installations (substations, switchyards, industrial power systems and related facilities).

Related standards

Key related documents include earlier editions/amendments of IEC 61936-1 (for historical reference), IEC 61936-2 / IEC TS 61936-2 (Part 2: DC installations — now published as IEC 61936-2:2023), IEC 60092 and IEC 61892 (marine and offshore), EN/BS national adoptions and CENELEC amendments (for example EN IEC 61936-1:2021/A11:2025), and other guidance such as IEEE 80 (touch‑voltage guidance) and EN 50522 (earthing in certain national contexts) where referenced or used in conjunction.

Keywords

High‑voltage installations; substations; switchgear; clearances; insulation coordination; earthing; touch voltage; protection systems; EMC; inspection and testing; design rules; IEC 61936.

FAQ

Q: What is this standard?

A: IEC 61936-1:2021 is an international standard that specifies design and erection requirements for AC power installations with nominal voltages above 1 kV, aimed at ensuring safety and correct functioning of those installations.

Q: What does it cover?

A: It covers fundamental design rules, clearances and insulation coordination, earthing systems and touch‑voltage criteria, protection and automation basics, EMC issues for control systems, installation of equipment (switchgear, transformers, busbars, cables), inspection and testing, and operation/maintenance documentation. It also specifies exclusions where other IEC series apply.

Q: Who typically uses it?

A: Electrical designers and engineers, utilities and grid operators, substation and plant contractors, testing and commissioning teams, safety/compliance officers and national standards/adoption bodies use this standard as a baseline for high‑voltage AC installations.

Q: Is it current or superseded?

A: IEC 61936-1:2021 is the current international edition (2021). In the European/national context there have been later amendments and European common modifications (for example EN IEC 61936-1:2021/A11:2025 published as a CENELEC amendment in late 2025 / early 2026); users should check national adoption documents and amendments that may apply locally.

Q: Is it part of a series?

A: Yes — IEC 61936 is a multi‑part work. Part 1 covers AC installations (this document) and Part 2 addresses DC installations (IEC 61936-2:2023). There are also related IEC technical specifications and national/EN adoptions that form the broader family of guidance for high‑voltage power installations.

Q: What are the key keywords?

A: High‑voltage, substations, switchgear, earthing, touch voltage, insulation coordination, clearances, protection systems, inspection and testing, IEC 61936-1.