IEC 60947-4-1:2018

Overview

IEC 60947-4-1:2018 is the fourth-edition international standard for low-voltage switchgear and controlgear covering electromechanical contactors and motor‑starters, including motor protective switching devices (MPSD), contactor-relay actuators, coil‑circuit contacts, and dedicated accessories. It applies to equipment intended for distribution, motor and other load circuits with rated voltages up to 1 000 V AC or 1 500 V DC. This 2018 edition replaces the 2009 edition and Amendment 1:2012 and includes significant technical revisions and new annexes.

Key topics and technical requirements

• Scope & classification: Defines kinds of equipment, poles, current types (AC/DC), utilization categories (AC-2/3/3e/4) and rated values.
• Constructional requirements: Materials, current-carrying parts, clearances/creepage, terminals, enclosures, limited energy and stored-charge circuits, and provisions for isolation and earthing.
• Performance & testing: Temperature-rise, dielectric properties, normal/overload performance, short‑circuit behaviour, and detailed type, routine and sampling tests. New requirements include pickup power measurement and tests for higher locked‑rotor currents to meet efficiency classes.
• Motor protective switching device (MPSD): New dedicated requirements, including short‑circuit breaking tests, coordination under short‑circuit conditions and overload relay characteristics.
• Safety aspects: General safety, limited energy circuits, electronic circuits, and an assessment procedure for electromechanical overload protection (Annex L).
• New annexes & additions:
  • Annex L: safety assessment for overload protection
  • Annex M: DC requirements for photovoltaic applications
  • Annex O: load monitoring indicators
  • Annex P: short‑circuit breaking tests of MPSD
  • Annex Q: coordination between MPSD and short‑circuit protective devices
• EMC, marking & documentation: Immunity/emission limits, marking, instructions for installation, maintenance and environmental information.
• Alignment & references: Aligned to IEC 60947‑1 editions and references IEC 62683‑1.

Applications and who uses it

• Manufacturers of contactors, motor‑starters and MPSDs for product design, conformity and test specifications.
• Test laboratories and certification bodies performing type and routine testing.
• Electrical engineers, panel builders and system integrators specifying low‑voltage motor control gear for industrial, commercial and photovoltaic systems.
• Safety assessors and maintenance teams ensuring correct selection, installation and coordination of protective devices.

Related standards

• IEC 60947‑1 (general rules for low‑voltage switchgear and controlgear) - alignment referenced throughout.
• IEC 62683‑1 - referenced for specific requirements.
• See also other parts of the IEC 60947 series for complementary device classes and auxiliary functions.

Keywords: IEC 60947-4-1, low-voltage switchgear and controlgear, electromechanical contactors and motor-starters, MPSD, photovoltaic DC requirements, short-circuit tests, load monitoring indicators.