EN IEC 60947 Low Voltage Switchgear and Control Equipment

The "EN IEC 60947 Low voltage switchgear and controlgear" standard, which is based on a European standard and subsequently published by the International Electrotechnical Commission (IEC), consists of the following subsections published under the same title:

• The standard “EN IEC 60947-1 Part 1: General rules”, when required by the relevant product standard, rated voltage 1000 Volt alternating current or 1500 Volt direct current It applies to low-voltage switchgear and controlgear intended to be connected to circuits not exceeding 100%. This standard specifies general rules and common safety requirements for low-voltage switchgear and controlgear, including: definitions, characteristics, information supplied with the equipment, normal service, installation and handling conditions, decommissioning and dismantling, structural and performance requirements, verification of characteristics and performance, energy efficiency aspects and environmental aspects.
• The standard "EN IEC 60947-2 Part 2: Circuit breakers" applies to circuit breakers whose main contacts are designed for connection to circuits having a nominal voltage not exceeding 1 000 Volts alternating current or 1 500 Volts direct current, and are intended to be installed and operated by trained or skilled persons. It also includes additional requirements for circuit breakers with integral fuses. This standard applies to circuit breakers rated at 1 000 Volts alternating current and below, as well as to circuit breakers with one or more ratings above 1 000 Volts alternating current but not exceeding 1 500 Volts direct current.
• The standard "EN IEC 60947-3 Part 3: Switches, disconnectors, switch-disconnectors and fuse combination units" applies to switches, disconnectors, switch-disconnectors and fuse combination units and their specific accessories for use in distribution circuits and motor circuits whose nominal voltage does not exceed 1 000 Volts alternating current or 1 500 Volts direct current. This fourth edition repeals and replaces the third edition, Amendment 1:2012 and Amendment 2:2015, published in 2008.
• The standard “EN IEC 60947-4-1 Part 4-1: Contactors and motor starters - Electromechanical contactors and motor starters” is applicable to the following equipment intended for connection to distribution circuits, motor circuits and other load circuits and having a nominal voltage not exceeding 1000 Volts alternating current or 1500 Volts direct current:
  • Electromechanical contactors and starters, including motor protection switching devices
  • Actuators of contactor relays
  • Contacts specifically dedicated to the coil circuit of the contactor or contactor relay
  • Special accessories (e.g. special wiring, special latch accessory)
• The standard “EN IEC 60947-4-2 Part 4-2: Contactors and motor starters - Semiconductor motor controllers, starters and soft starters” applies to semiconductor motor controllers, starters and soft starters, which may include a mechanical device with series switching, designed to be connected to circuits whose nominal voltage does not exceed 1 000 Volts alternating current.
• The standard "EN IEC 60947-4-3 Part 4-3: Contactors and motor starters - Semiconductor controllers and semiconductor contactors for non-motor loads" applies to semiconductor controllers and semiconductor contactors for non-motor loads intended to be connected to circuits whose nominal voltage does not exceed 1 000 Volts alternating current. Their use is as follows
  • For changing the state of alternating current electrical circuits between on and off
  • With or without bypass switching devices
  • As a controller to reduce the amplitude of RMS alternating current voltage.
• The standard "EN IEC 60947-5-1 Part 5-1: Control circuit devices and switching elements - Electromechanical control circuit devices" applies to control circuit devices and switching elements designed for control, signaling, interlocking and similar functions in switchgear and control devices. This standard applies to control circuit devices having a nominal voltage not exceeding 1000 Volts alternating current (at a frequency not exceeding 1000 Hz) or 600 Volts direct current.
• The standard “EN IEC 60947-5-2 Part 5-2: Control circuit devices and switching elements - Proximity switches” applies to inductive and capacitive proximity switches that detect the presence of metallic or non-metallic objects, ultrasonic proximity switches that detect the presence of sound-reflecting objects, photoelectric proximity switches that detect the presence of objects and non-mechanical magnetic proximity switches that detect the presence of objects with a magnetic field.
• The standard "EN IEC 60947-5-3 Part 5-3: Control circuit devices and switching elements - Requirements for proximity devices with defined behavior under fault conditions (PDDB)" provides additional requirements to those given in EN IEC 60947-5-2. It addresses the fault performance aspects of proximity devices with defined behavior under fault conditions (PDDB). Other features that may be required for specific applications are not addressed in this standard.
• The standard "EN IEC 60947-5-4 Part 5-4: Control circuit devices and switching elements - Method for evaluating the performance of low-energy contacts - Specific tests" applies to separable contacts used in the intended field of use, such as switching elements for control circuits. This standard considers two nominal voltage areas:
  • Above 10 Volts (typically 24 Volts inclusive) where contacts are used to switch loads with potential electrical wear, such as programmable controller inputs
  • Below 10 Volts (usually 5 Volts) there is negligible electrical wear, such as electronic circuits.
• The standard "EN IEC 60947-5-5 Part 5-5: Control circuit devices and switching elements - Electrical emergency stop device with mechanical interlocking function" applies to electrical control circuit devices and switching elements used to provide an emergency stop signal. Such devices can be supplied either with their own enclosure or installed in accordance with the manufacturer's instructions.
• The standard "EN IEC 60947-5-6 Part 5-6: Control circuit devices and switching elements - DC interface for proximity sensors and switching amplifiers (NAMUR)" applies to proximity sensors connected to the control input of a switching amplifier for operation via a two-wire connecting cable. The switching amplifier contains direct current. It is the source that supplies the control circuit and is controlled by the variable internal resistance of the proximity sensor. These devices can be used in explosive atmospheres if they comply with IEC 60079-11.
• The standard "EN IEC 60947-5-7 Part 5-7: Control circuit devices and switching elements - Proximity devices with analogue output" specifies the requirements for proximity devices corresponding to the scope of EN IEC 60947-5-2, with analogue output (PDAO) or digital output, to transmit the corresponding digital value representing the detected sensing input. These devices may provide additional parameters.
• The standard "EN IEC 60947-5-8 Part 5-8: Control circuit devices and switching elements - Three-position enabling switches" specifies the requirements for three-position enabling switches. These switches are used as components that enable devices to provide signals,
  • When enabled, allows the machine's operation to be initiated by a separate start control
  • When disabled, it initiates a stop function and prevents the machine from starting.
• The standard "EN IEC 60947-5-9 Part 5-9: Control circuit devices and switching elements - Flow rate switches" applies to flow rate switches that sense the flow rate of a gas, liquid or granular solid. These switches change their output state when a preset value for the flow rate is exceeded. These flow rate switches are self-contained, have a semiconductor switching element(s) and are designed for connection to circuits having a nominal voltage not exceeding 250 Volts 50/60 Hz alternating current or 300 Volts direct current.
• The standard “EN IEC 60947-6-1 Part 6-1: Multifunctional equipment - Transfer switching equipment” applies to transfer switching equipment used to ensure continuity of supply in power systems and to enable energy management of the facility by transferring loads between power sources whose nominal voltage does not exceed 1000 Volts alternating current or 1500 Volts direct current.
• The standard "EN IEC 60947-6-2 Part 6-2: Multifunctional equipment - Control and protective switching devices (or equipment) (CPS)" applies to control and protective switching devices (or equipment) (CPS) whose main contacts are intended to be connected to circuits with a nominal voltage not exceeding 1 000 Volts alternating current or 1 500 Volts direct current. This standard covers the following types of control and protective switching devices:
  • Providing protection and control functions for circuits and motors
  • The control function is operated not only manually but also in another way
  • Ensuring continuity of service after overcurrent conditions
  • Having additional functions such as isolation or communication
• The standard "EN IEC 60947-7-1 Part 7-1: Auxiliary equipment - Terminal blocks for copper conductors" specifies the requirements for terminal blocks and test disconnect terminal blocks in accordance with Annex D, with screw or screwless type clamping units, primarily intended for industrial or similar use and intended to be fixed to a support to provide the electrical and mechanical connection between copper conductors. This standard applies to terminal blocks, with or without special preparation, designed to connect round copper conductors with a cross-sectional area between 0,05 mm2 and 300 mm2, intended for use in circuits with a nominal voltage of 1 000 V alternating current up to 1 000 Hz or 1 500 V direct current. Tests on terminal blocks are carried out with alternating current or direct current in accordance with the requirements specified in the relevant clauses of this document.
• The standard "EN IEC 60947-7-2 Part 7-2: Ancillary equipment - Protective conductor terminal blocks for copper conductors" specifies the requirements for protective conductor terminal blocks with PE function up to 120 mm² and protective conductor terminal blocks with screw or screwless clamping units for PEN function from 10 mm² and larger, primarily intended for industrial applications. Protective conductor terminal blocks are used to create the electrical and mechanical connection between copper conductors and the fixing support. This applies to protective conductor terminal blocks for the connection of round copper conductors with or without special preparation having a cross-sectional area between 0,2 mm² and 120 mm² and intended for use in circuits having a rated voltage not exceeding 1 000 V alternating current up to 1 000 Hz or 1 500 V direct current, often in combination with terminal blocks in accordance with IEC 60947-7-1. This standard can be used as a guide for:
  • Protective conductor terminal blocks that require special devices to be fixed to the conductors, e.g. quick-connect terminations or wrap-around connections
  • Protective conductor terminal blocks that provide direct contact to conductors via edges or points that penetrate the insulation, e.g. insulation displacement connections
• EN IEC 60947-7-3 Part 7-3: Ancillary equipment - Safety requirements for fuse terminal blocks This standard applies to fuse terminal blocks having screw or screwless type clamping units for connecting rigid (solid or stranded) or flexible copper conductors for receiving cartridge fuse connectors in accordance with EN IEC 60127-2. They are primarily intended for industrial or similar use in circuits not exceeding 1 000 Volts alternating current, up to 1 000 Hz or 1 500 Volts direct current, and have a maximum short-circuit breaking capacity of 1 500 A. They are intended for installation in electrical equipment having enclosures surrounding the fuse terminal blocks that are accessible only by means of a tool. For some applications, for example in control circuits, fuse terminal blocks may be designed for short-circuit protection only. The purpose of this standard is to specify the safety requirements and test methods for the mechanical, electrical and thermal characteristics of fuse terminal blocks in order to ensure compatibility between the terminal blocks and standard fuse-links. This standard can be used as a guide for:
  • Fuse terminal blocks that require special devices to be fixed to the conductors, such as quick-connect terminations or wrap-around connections
  • Fuse terminal blocks that provide direct contact with conductors via edges or points that penetrate the insulation, e.g. insulation displacement connections
• The standard "EN IEC 60947-7-4 Part 7-4: Auxiliary equipment - PCB terminal blocks for copper conductors" specifies the requirements for printed circuit board terminal blocks primarily designed for industrial or similar use. Mounting and fixing to the printed circuit board are carried out by soldering, crimping or equivalent methods to ensure electrical and mechanical connection between the copper conductors and the printed circuit board. This standard applies to PCB terminal blocks designed to connect copper conductors with cross sections between 0,08 mm2 and 300 mm2, with or without special preparation, and intended for use in circuits with a nominal voltage of 1 000 V alternating current up to 1 000 Hz2e or 1 500 V direct current.
• The standard "EN IEC 60947-7-5 Part 7-5: Auxiliary equipment - Terminal blocks for aluminium conductors" specifies the requirements for terminal blocks with screw or screwless type clamping units, primarily intended for industrial or similar use, which must be fixed to a support to provide electrical and mechanical connections. This document can be used for terminal blocks used for connections between aluminium conductors or aluminium-copper conductors. This regulation applies to terminal blocks designed to connect round conductors with cross-sections between 2,5 mm² and 300 mm², with or without special preparation, and intended for use in circuits having a nominal voltage not exceeding 1 000 Volts alternating current (up to 1 000 Hz) or 1 500 Volts direct current.
• The standard “EN IEC 60947-8 Part 8: Internal thermal protection (PTC) control units for rotating electrical machines” specifies requirements for control units that control a switching device in response to PTC thermistors incorporated into rotating electrical machines and industrial application.
• The standard "EN IEC 60947-9-1 Part 9-1: Active arc fault reduction systems - Arc extinguishing devices" covers low-voltage arc extinguishing devices designed to eliminate arc faults in low-voltage assemblies (typically low-voltage switchgear and controlgear conforming to the IEC 61439 series of standards). These devices are designed to eliminate arc faults in low-voltage assemblies (typically low-voltage switchgear and controlgear conforming to the IEC 61439 series of standards) by creating a lower-impedance current path, allowing the arc current to be transferred to the new current path. This new current path is maintained until the short-circuit protective device interrupts the short-circuit current. Arc extinguishing devices are installed in low-voltage assemblies connected to the main circuit, as close as possible to all primary power sources. Their rated voltage does not exceed 1000 Volts alternating current or 1500 Volts direct current.

The following are outside the scope of this standard:

• Sensors designed to detect arc faults
• Devices designed to trigger arc extinguishing device operation
• Devices for interrupting arc fault current
• Special requirements for arc extinguishing devices for use in explosive atmospheres (e.g. ATEX)

• Detects internal arc faults in low-voltage switchgear and controlgear assemblies by processing the optical effect of (at least) an internal arc fault
• Operating the reduction device (external or combined) to minimize the effects of internal arc fault

• Semiconductor circuit breakers have semiconductor switching elements and mechanical switching elements connected in series for the isolating function.
• Semiconductor hybrid circuit breakers are circuits in which semiconductor switching elements and mechanical switching elements are connected in parallel and, in addition, mechanical switching elements are connected in series for the isolation function.

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