Electrical equipment for machine safety

Equipment such as machine tools and robots has been used extensively in a variety of manufacturing sectors for decades. Individuals working with, or in close proximity to, these machines are reliant on their safe operation for protection, as are nearby installations.

Any industrial machine that may cause accidents must be safeguarded.  The addition of electrical equipment such as electromechanical sensors and switches that can activate safeguarding mechanisms - to keep operators at a safe distance or halt operation automatically in case of danger - can prevent accidents occurring or reduce their severity.

Among the many IEC TCs that prepare International Standards for these devices, IEC TC 44 is notable as it aims to protect users from the risks posed by all kinds of machines by preparing standards for electrical equipment associated with machinery.

Industrial machines may be powered by kinetic, electrical, hydraulic or pneumatic energy. Whatever the source, there are often similar safety issues. By adding electrical equipment, individuals can be prevented from coming too close to, or interfering with, machinery in operation. The addition also enables machines to be shut down in case of malfunction or failure. The added equipment may help prevent injuries or even death occurring.

International Standards developed by TC 44 include general and specific requirements for different types of electrical equipment used with machines. They may concern indication, marking and actuation - including visual, acoustic and tactile signals - as well as the location and operation of actuators.

TC 44 International Standards also cover ESPE (electro-sensitive protective equipment), such as various kinds of AOPDs (active optoelectronic protective devices) and other equipment designed to detect human presence. TC 44 was created in 1957 to develop safety-related standards for electrical equipment associated with industrial machines, particularly machine tools and large machinery. Its present activities comprise three main elements: preparation of International Standards relating primarily to non-portable electrotechnical equipment and machinery systems, including machinery assemblies; preparation of International Standards for electrotechnical equipment and systems relating to the protection of persons from specific machinery hazards, taking into account a coordinated systems approach; coordination with ISO (International Organization for Standardization) on all matters concerning the safety of machinery.

The following technology tends have an impact on the TC’s work: safety functions; functional safety, including software; development and application of smart sensors; remote diagnostics of plant and equipment; use of communication networks (bus systems) for machinery safety-related control functions; cableless control; switching devices on semiconductor basis.

Market trends also drive safety considerations. Industrial machines are not produced, traded and operated in a single country but globally. International customers expect to be presented with common solutions that can be used in several countries. This allows them to harmonise their sites and plants globally to rationalise their production procedures and to save costs through the globally organised purchase of production equipment. These TC 44 International Standards are increasingly applicable worldwide.

For developing International Standards covering a wide range of equipment, TC 44 is organised into 4 WGs (Working Groups), one Project Team that looks at requirements for the electrical equipment for machine tools, 7 MTs (Maintenance Teams) for existing standards, and a JWG (Joint Working Group) with ISO TC 199: Safety of machinery.

TC 44 aims to keep its International Standards up to date to reflect new and changing technologies and to ensure they are state of the art at the time they are drafted. It states that it will work with ISO TC 199 to merge IEC 62061 and ISO 13849-1 into a dual logo IEC/ISO standard. As industrialisation extends to more and more countries, and automation is introduced to all sectors, the safety of industrial machines, which are traded on a global scale, becomes ever more important. The work of IEC TC 44 experts, which is constantly being updated and expanded, will, therefore, remain essential to ensure that the safe operation of machinery throughout the world continues to increase.