IEC 61386-21:2021

Overview

IEC 61386-21:2021 - "Conduit systems for cable management - Part 21: Particular requirements - Rigid conduit systems" - specifies requirements, tests and documentation for rigid conduit systems used for cable management. This second edition (2021) cancels and replaces the 2002 edition and is a technical revision. It is to be used together with IEC 61386-1:2008 and IEC 61386-1:2008/AMD1:2017 and supplements or modifies their clauses where indicated.

Key Topics and Requirements

• Scope and classification
  • Defines classification rules specific to rigid conduits and notes national restrictions (e.g., certain classifications not allowed in France).
• Marking and documentation
  • Continuous marking along conduit length (preferably every 1 m, max 3 m) and documentation of minimum inside diameter and classification (see 7.1.101–7.1.102).
  • New requirement (7.1.103): manufacturer must declare whether the conduit is bendable and supply bending instructions and aids if needed.
• Dimensions and threads
  • Threads and outside diameters follow IEC 60423; tables in the standard give thread lengths and maximum entry diameter / minimum entry length for sizes (e.g., sizes 6–75).
• Construction and mechanical properties
  • Detailed mechanical tests (compression, bending, collapse) and pass/fail criteria.
  • Compression test guidance: Annex AA provides calculation and tolerances for applying a constantly increasing force (10.2.4) - ensures uniform force ramp (example: 750 N test force → 25 N/s over 30 s).
  • Bending test (10.4): conduits declared bendable are tested (e.g., metallic sizes 16, 20, 25 bent to 90° ±5° with inside radius = 6×nominal diameter); post-test checks for cracking, seam opening and section distortion.
• Other properties
  • Electrical, thermal, fire-hazard, external influences and electromagnetic compatibility requirements are referenced and supplemented from Part 1.
• Annexes and figures
  • Normative annexes cover classification coding, material thickness determination and additional tests; informative Annex AA explains force application for compression testing. Figures illustrate bending apparatus and gauges.

Practical Applications

• Specifies how to manufacture, test and label rigid conduit systems for:
  • Electrical accessory manufacturers and component suppliers
  • Test laboratories and conformity assessors
  • System specifiers, designers and engineers for buildings, industrial and infrastructure projects
  • Installers and contractors needing to verify product documentation and marking
• Helps ensure mechanical integrity, safe installation (bending guidance) and traceability for cable protection systems.

Who Should Use This Standard

• Product designers, quality managers, testing labs, certification bodies, electrical contractors and procurement teams specifying rigid conduit systems for compliance and safety.

Related Standards

• IEC 61386-1:2008 (General requirements) - mandatory companion document
• IEC 61386-1:2008/AMD1:2017 (Amendment)

Keywords: IEC 61386-21:2021, rigid conduit systems, conduit systems for cable management, bending test, compression test, marking, conduit classification, IEC standard