IEC 60999-2:2003

Overview

IEC 60999-2:2003 is an international safety standard developed by the International Electrotechnical Commission (IEC) that specifies requirements for screw-type and screwless-type clamping units used for connecting electrical copper conductors. This standard is specifically focused on clamping units suitable for conductors with cross-sections above 35 mm² and up to 300 mm², including equivalent American Wire Gauge (AWG)/kcmil sizes. It addresses both rigid stranded and flexible copper conductors compliant with IEC 60228, for electrical circuits with rated voltages not exceeding 1,000 V a.c. (up to 1,000 Hz) and 1,500 V d.c.

This document provides guidance to manufacturers, technical committees, equipment designers, and test laboratories to ensure the safe and reliable connection of large copper conductors in electrical systems. IEC 60999-2 serves as a group safety publication according to IEC Guide 104 and should be utilized in conjunction with IEC 60999-1 for comprehensive requirements.

Key Topics

• Scope and Applicability:

  • Applies to clamping units as separate devices or as integral parts of electrical equipment.
  • Covers connections for unprepared copper conductors above 35 mm² up to and including 300 mm² (and equivalent AWG/kcmil).
  • Excludes clamping units for crimping, soldering, and certain non-universal types.

• Conductor Compatibility:

  • Defines requirements for rigid stranded and/or flexible copper conductors.
  • Standardized rated cross-sections: 50 mm², 70 mm², 95 mm², 120 mm², 150 mm², 185 mm², 240 mm², and 300 mm².
  • Guidance provided on the use of international wire gauge systems (AWG/kcmil).

• Constructional Requirements:

  • Main current-carrying parts must be made of copper or copper alloys with specific minimum copper content, or other corrosion-resistant metals with equivalent properties.
  • Clamping units should accept unprepared conductors and clearly indicate compatibility with rigid or flexible types if limited.
  • Connection and disconnection processes for screwless types should utilize common tools or integrated mechanisms.

• Testing and Safety:

  • Specifies test procedures for verifying insertion and clamping of conductor sizes, as well as durability through multiple connection/disconnection cycles.
  • Mechanical strength, conductor retention, and prevention of conductor strand escape are critical aspects.
  • Compliance checked by inspection and prescribed mechanical and electrical tests.

Applications

IEC 60999-2:2003 is relevant for a variety of electrical applications where large copper conductors are used. Common areas of use include:

• Low-voltage energy distribution panels
• Industrial switchgear and controlgear assemblies
• Power equipment such as busbars, switchboards, and motor control centers
• Electrical installations in commercial and infrastructure projects requiring robust connections for high-capacity circuits

The standard is essential for manufacturers and product designers to ensure compliance and safety in heavy-duty electrical connector systems. Test laboratories also use these guidelines to certify products that involve large conductor connections.

Related Standards

• IEC 60999-1: Connecting devices - Electrical copper conductors - Safety requirements for screw-type and screwless-type clamping units - Part 1: General requirements and particular requirements for clamping units for conductors from 0.2 mm² up to 35 mm².
• IEC 60228: Conductors of insulated cables (specifies conductor types and sizes referenced in this standard).
• IEC Guide 104: Provides principles for group safety publications.

Practical Value

Adhering to IEC 60999-2:2003 ensures electrical safety, reliable performance, and international compliance for devices connecting large copper conductors. It reduces the risk of loose connections, overheating, and potential system failures, supporting the safe operation and maintenance of high-capacity electrical installations worldwide. Manufacturers and electrical engineers benefit from the structured requirements and clear guidance provided, facilitating safe and standardized product development and application.