IEC 60947-7-2:2009

Overview

IEC 60947-7-2:2009 is an international standard published by the International Electrotechnical Commission (IEC) that specifies requirements for protective conductor terminal blocks used with copper conductors in low-voltage switchgear and controlgear. Part 7-2 of IEC 60947 focuses on ancillary equipment, namely protective conductor terminal blocks with PE (protective earth) and PEN (combined protective earth and neutral) functions.

These terminal blocks are designed for industrial applications and allow secure electrical and mechanical connections between copper conductors and fixing supports. The standard covers terminal blocks suitable for round copper conductors with cross-sections from 0.2 mm² to 120 mm² (AWG 24 to 250 kcmil), intended for circuits rated up to 1000 V AC (up to 1000 Hz) or 1500 V DC.

This edition includes updated requirements for tightening torques and improved test procedures, particularly for short-time withstand current testing, ensuring enhanced safety and reliability in electrical installations.

Key Topics

• Scope and Application
  Covers protective conductor terminal blocks for copper conductors, including PE function blocks (up to 120 mm²) and PEN function blocks (from 10 mm² with screw or screwless clamping units) primarily for industrial use.

• Product Types and Features
  Includes screw-type and screwless-type clamping units designed for reliable mechanical and electrical connections. Supports round conductors with or without special preparation.

• Technical Requirements
  Specifies rated cross-sections, rated connecting capacities, rated voltages, short-time withstand current, temperature rise limitations, dielectric properties, and voltage drop criteria to ensure optimal performance.

• Testing and Verification
  Defines comprehensive mechanical, electrical, thermal, and electromagnetic compatibility (EMC) tests, including temperature-rise tests, voltage drop verification, dielectric tests, and ageing tests for screwless terminal blocks.

• Marking and Identification
  Requires clear marking of terminal blocks for safe identification and compliance tracking, facilitating inspection and maintenance.

• Compatibility
  Designed for use alongside terminal blocks covered in IEC 60947-7-1 for comprehensive low-voltage switchgear assemblies.

Applications

IEC 60947-7-2 compliant protective conductor terminal blocks are essential components in electrical distribution and control systems, especially in industrial installations requiring:

• Safe and reliable protective earth connections to prevent electrical shock hazards.
• Secure mechanical fixation for copper conductors in switchgear and controlgear assemblies.
• Support for quick-connect terminations and insulation displacement connections, enabling efficient wiring practices.
• Use in circuits with rated voltages up to 1000 V AC or 1500 V DC, featuring high short-time withstand current capacity.
• Industrial environments where robust electrical connections and compliance with international safety standards are mandatory.

These terminal blocks are widely used in manufacturing plants, machinery control panels, electrical distribution boards, and other industrial electrical systems requiring high standards of protective conductor connection integrity.

Related Standards

• IEC 60947-1:2007 – General rules for low-voltage switchgear and controlgear, providing foundational requirements applicable to IEC 60947-7-2.
• IEC 60947-7-1:2009 – Requirements for terminal blocks for copper conductors without PE function, complementing IEC 60947-7-2.
• IEC 60947 series – Comprehensive standards for low-voltage switchgear and controlgear covering various components and ancillary equipment.
• ISO/IEC Directives Part 2 – Guidelines for the drafting and format of international standards ensuring consistency and quality.

By adhering to IEC 60947-7-2, manufacturers and engineers ensure protective conductor terminal blocks meet rigorous international benchmarks for safety, performance, and interoperability in low-voltage electrical installations.