IEC 60947-5-8:2020 PDF

Low-voltage switchgear and controlgear - Part 5-8: Control circuit devices and switching elements - Three-position enabling switches

First page of standard IEC 60947-5-8:2020

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Title (English):

IEC 60947-5-8:2020

Low-voltage switchgear and controlgear - Part 5-8: Control circuit devices and switching elements - Three-position enabling switches

Document status:: Active
Format:: Electronic (PDF)
Number of pages:: 77
Publication date:: August 12, 2020
Edition:: IEC IS 60947 edition 2 version 1
ICS:: 29.130.20

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Description (English):

IEC 60947-5-8:2020 specifies requirements for three-position enabling switches. These switches are used as components of enabling devices to provide signals that, - when activated, allow machine operation to be initiated by a separate start control, and - when de-activated, -- initiate a stop function, and -- prevent initiation of machine operation. This second edition cancels and replaces the first edition published in 2006. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - due to the increasing range of useful applications of three-position enabling switches, note of scope, operational characteristics and tests are reviewed; - figures for example of devices incorporating enabling switch are added in Annex A; - new Annex B for procedure to determine reliability data for the switch used in functional safety applications is added.

Technical details

Technical committee: SC 121A - Low-voltage switchgear and controlgear
SKU: IEC 60947-5-8:2020

Abstract

Overview

IEC 60947-5-8:2020 is the International Electrotechnical Commission (IEC) standard that defines requirements for three-position enabling switches used in low-voltage switchgear and controlgear. Edition 2.0 (2020) replaces the 2006 edition and updates scope, operational characteristics and tests. The standard covers three-position enabling switches intended for electrical control circuits with rated voltages up to 250 V AC (50/60 Hz) or 300 V DC. It specifies construction, performance, testing and product information for switches that form part of enabling devices used to permit, prevent or stop machine operation.

Key topics and technical requirements

Function and definition: A three-position enabling switch has three sequential actuator positions; the enabling contact is closed only in the mid position and open in the rest and fully depressed positions.
Scope of use: Intended as components of enabling devices that, when continuously actuated, allow machine operation to be initiated by a separate start control, and when deactivated, initiate a stop and prevent restart.
Construction & performance: Requirements for actuating systems, contact elements, number of poles, and mechanical characteristics are specified (see clauses on characteristics, construction and tests).
Environmental & mechanical tests: Normal service, mounting and transport conditions plus tests for shock, vibration and durability are included (referenced from IEC 60068 series).
Product information & marking: Manufacturers must provide key product information and ratings for safe integration.
Functional safety support: Annex B (new in 2020) provides a procedure to determine reliability data for use in functional safety applications (useful for safety lifecycle and risk assessments).
Examples: Annex A (informative) adds figures showing typical devices incorporating three-position enabling switches (grip, pendant, foot-actuated, joystick, etc.).

Applications and who should use this standard

Machine builders and integrators designing human-operated safety controls (grip handles, push-buttons, foot pedals, teaching pendants).
Functional safety engineers performing risk assessments and calculating reliability data for safety-related control systems.
Switch manufacturers and designers developing three-position enabling switches and needing to meet IEC performance and testing requirements.
Test laboratories and certification bodies verifying compliance for low-voltage control devices. Practical applications include assembly robots, hand-held and portable machine controls, operator pendants and any system requiring a deliberate enabling function to allow safe machine operation.

Related standards

IEC 60947-1 (General rules for low-voltage switchgear and controlgear)
IEC 60947-5-1 (Electromechanical control circuit devices)
IEC 60204-1 (Safety of machinery - electrical equipment of machines) These documents should be used in conjunction with IEC 60947-5-8 for complete compliance and system-level safety design.

Keywords: IEC 60947-5-8, three-position enabling switches, low-voltage switchgear, enabling device, machine safety, functional safety, reliability data, enabling contact.

Related standards

Standards mentioned in the description

Abstract

Overview

Key topics and technical requirements

Function and definition: A three-position enabling switch has three sequential actuator positions; the enabling contact is closed only in the mid position and open in the rest and fully depressed positions.
Scope of use: Intended as components of enabling devices that, when continuously actuated, allow machine operation to be initiated by a separate start control, and when deactivated, initiate a stop and prevent restart.
Construction & performance: Requirements for actuating systems, contact elements, number of poles, and mechanical characteristics are specified (see clauses on characteristics, construction and tests).
Environmental & mechanical tests: Normal service, mounting and transport conditions plus tests for shock, vibration and durability are included (referenced from IEC 60068 series).
Product information & marking: Manufacturers must provide key product information and ratings for safe integration.
Functional safety support: Annex B (new in 2020) provides a procedure to determine reliability data for use in functional safety applications (useful for safety lifecycle and risk assessments).
Examples: Annex A (informative) adds figures showing typical devices incorporating three-position enabling switches (grip, pendant, foot-actuated, joystick, etc.).

Applications and who should use this standard

Machine builders and integrators designing human-operated safety controls (grip handles, push-buttons, foot pedals, teaching pendants).
Functional safety engineers performing risk assessments and calculating reliability data for safety-related control systems.
Switch manufacturers and designers developing three-position enabling switches and needing to meet IEC performance and testing requirements.
Test laboratories and certification bodies verifying compliance for low-voltage control devices. Practical applications include assembly robots, hand-held and portable machine controls, operator pendants and any system requiring a deliberate enabling function to allow safe machine operation.

Related standards

IEC 60947-1 (General rules for low-voltage switchgear and controlgear)
IEC 60947-5-1 (Electromechanical control circuit devices)
IEC 60204-1 (Safety of machinery - electrical equipment of machines) These documents should be used in conjunction with IEC 60947-5-8 for complete compliance and system-level safety design.

Keywords: IEC 60947-5-8, three-position enabling switches, low-voltage switchgear, enabling device, machine safety, functional safety, reliability data, enabling contact.

IEC 60947-5-8:2020 PDF

Technical details

Abstract

Overview

Key topics and technical requirements

Applications and who should use this standard

Related standards

Related standards

Abstract

Overview

Key topics and technical requirements

Applications and who should use this standard

Related standards

Related standards

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