IEC 60445:2021

Overview

IEC 60445:2021 - Basic and safety principles for man‑machine interface, marking and identification - specifies rules for the identification and marking of equipment terminals, conductor terminations and conductors. Edition 7.0 (2021) is a technical revision that replaces the 2017 edition and has the status of a basic safety publication under IEC Guide 104. The standard provides general rules for using colours and alphanumeric notations on cables, cores, busbars and electrical equipment to avoid ambiguity and support safe operation.

Key topics and requirements

• Scope: Applies to terminals of electrical equipment (e.g., resistors, fuses, relays, contactors, transformers, rotating machines) and to terminations of certain designated conductors; intended primarily for use by technical committees preparing standards.
• Identification methods: Defines permitted methods including single colours, bi‑colour combinations and alphanumeric markings for terminals and conductors.
• Colour identification: Specifies colours and combinations for designated conductors (e.g., protective, neutral, PEN/PEL/PEM) and makes the colour provisions requirements, not mere recommendations, in this edition.
• Alphanumeric notation: Rules for terminal and conductor marking using letters/numbers to avoid ambiguity in diagrams and on equipment.
• New technical content (2021):
  • Definitions aligned with IEC 60050‑195:2021 and IEC 60050‑826.
  • Colour usage for specific conductors elevated to mandatory requirements.
  • New subclause for marking protective terminals on equipment with multiple power‑supply inputs.
• Informative annexes: Colour, notation and graphical symbol tables, plus country‑specific notes on differing practices.

Practical applications

• Provides the foundational safety principles used when drafting detailed standards that govern marking and identification in equipment and installations.
• Helps ensure consistent, unambiguous identification across:
  • Control panels, switchgear and motor terminals
  • Cable harnesses, busbars and installation wiring
  • Engineering drawings, schematics and product documentation
• While the publication is primarily aimed at standards developers, the rules it contains are directly relevant to electrical engineers, panel builders, system integrators and technical authors who implement or reference mandated marking schemes in products and installations.

Intended audience

• Primary: IEC technical committees and standards developers preparing normative documents in line with IEC Guide 104 and ISO/IEC Guide 51.
• Secondary (useful reference): electrical designers, documentation specialists and safety engineers who need to align marking practices with internationally recognized basic safety principles.

Related standards

• IEC 60050‑195 and IEC 60050‑826 (terminology)
• IEC 60417 (graphical symbols for equipment)
• IEC 60617 (graphical symbols for diagrams)
• IEC Guide 104; ISO/IEC Guide 51 (safety publication principles)

Keywords: IEC 60445:2021, identification of equipment terminals, conductor identification, conductor colours, alphanumeric notation, marking, basic safety publication, man‑machine interface.