IEC 60947-7-4:2019

Overview

IEC 60947-7-4:2019 is the IEC international standard for PCB terminal blocks for copper conductors, part of the Low‑voltage switchgear and controlgear series. It specifies construction, performance and test requirements for terminal blocks mounted on printed circuit boards by soldering, press‑in or equivalent methods. The standard applies to terminal blocks for copper conductors with cross‑sections from 0.08 mm² to 300 mm² (AWG 28–600 kcmil) and for use in circuits of up to 1 000 V AC (to 1 000 Hz) or 1 500 V DC. Edition 2.0 (2019) replaces the 2013 edition and introduces several technical revisions.

Key topics and technical requirements

• Scope and ratings
  • Rated voltages and currents, standard cross‑sections and maximum connectable conductor sizes.
• Mounting and mechanical construction
  • Requirements for soldered, press‑in and equivalent PCB fixing; clearances, creepage distances and terminal identification.
• Clamping units and tightening torques
  • Tests and construction requirements for screw, spring and other clamping methods; tightening torques for screw‑type clamping units are specified (see Table 4).
• Electrical performance and tests
  • Dielectric and impulse withstand tests, contact resistance verification (new criteria introduced), temperature‑rise (current‑temperature derating) tests and short‑time withstand current tests.
• Ageing and thermal tests
  • Procedures for current cycling, ageing tests and verification of long‑term performance.
• Special tests
  • New/additional test for PCB terminal blocks where contact pressure is transmitted via insulating materials.
• Electromagnetic compatibility (EMC)
  • Immunity and emission considerations for terminal blocks used in populated PCBs.
• Documentation and marking
  • Manufacturer marking, product information and additional data exchange between manufacturer and user (Annex B).

Applications and who uses this standard

IEC 60947-7-4:2019 is used by:

• Terminal block and connector manufacturers for product design, testing and certification.
• Switchgear and controlgear designers specifying PCB terminal blocks in industrial control panels, motor controllers and instrumentation.
• PCB designers and electrical engineers for layout and current‑carrying capacity decisions, including high‑current PCB design (see Annex C).
• Test laboratories and conformity assessors performing dielectric, thermal and mechanical verification.
• Procurement and compliance teams ensuring components meet rated voltages, cross‑sections and safety requirements.

Related standards

• IEC 60947 series (general requirements for low‑voltage switchgear and controlgear)
• IEC 60947‑1 referenced for broader definitions and system‑level requirements

Keywords: IEC 60947-7-4:2019, PCB terminal blocks, low‑voltage switchgear, printed circuit board, copper conductors, contact resistance, temperature‑rise test, tightening torque, clamping units, EMC.