IEC 60445:2017

Overview

IEC 60445:2017 - Basic and safety principles for man‑machine interface, marking and identification - specifies principles for the identification and marking of equipment terminals, conductor terminations and conductors. It applies to terminals of electrical equipment (resistors, fuses, relays, contactors, transformers, rotating machines, assemblies) and to the terminations of certain designated conductors. The publication is a basic safety publication (IEC Guide 104) and the 2017 sixth edition updates terminology and colour/notation rules to reduce ambiguity and improve safety in electrical installations and documentation.

Key topics and technical requirements

• Scope and purpose: establishes general rules for marking terminals and designated conductors to ensure clear man‑machine interface and safe operation.
• Methods of identification: covers marking techniques for terminals, terminations and conductors (colours, bi‑colour combinations, alphanumeric notations and graphical symbols).
• Identification by colours: normative guidance for permitted single colours and bi‑colour combinations used to identify neutral, line conductors (AC and DC), protective conductors and functional earthing conductors. (Table A.1 provides the consolidated colour and notation references.)
• Alphanumeric notation: principles for terminal and conductor labelling where colour alone is not sufficient or practical - includes conventions for neutral, protective (PE), PEN, PEL, PEM, mid‑point, functional earthing and functional bonding conductors.
• Terminal marking principles: rules for marking single elements, multi‑terminal devices and grouped equipment so that function and interconnections are unambiguous.
• Edition changes: sixth edition adds colour codes for DC line conductors, a colour code for functional earthing conductors, updates Table A.1, converts non‑mandatory notes to normative text, and aligns terminology with IEC 60050‑195.

Practical applications

• Use as a reference when defining conductor colouring and terminal marking in standards, wiring diagrams and technical documentation.
• Helps prevent misidentification of conductors and terminals during design, installation, maintenance and troubleshooting, reducing risk of electrical faults and safety incidents.
• Applicable to cables/cores, busbars, electrical equipment and installations where consistent marking is needed.

Who uses this standard

• Primary audience: IEC technical committees and standards writers preparing normative documents in line with IEC Guide 104.
• Secondary audiences: electrical engineers, system designers, panel builders, safety engineers and specifiers who reference IEC 60445 when adopting marking conventions in product or installation standards (note: the document itself is primarily intended for use by technical committees).

Related standards

• IEC Guide 104 (basic safety publications)
• ISO/IEC Guide 51 (safety aspects in standards)
• IEC 60050‑195 (terminology alignment)
• IEC 60417 and IEC 60617 (graphical symbols)

Keywords: IEC 60445, conductor identification, terminal marking, colour code, alphanumeric notation, functional earthing, protective conductor, man‑machine interface.