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The paper aims to address what types of protection can be applied to galvanic elements and batteries that are used in potentially explosive atmospheres. In order to keep electrical equipment in operation in environments with potentially explosive atmospheres under harsh conditions, including galvanic elements and batteries, a certain type of protection must be applied for safe operation. The types of protection applied to galvanic elements and batteries are made in accordance with EN 60079-0 and in compliance with the requirements of the ATEX directive - 2014-34 EU. Galvanic cells and batteries in order to be used in potentially explosive environments must meet certain conditions, namely: All galvanic cells in a battery must have the same electrochemical system, design and rated capacity, and must be made by the same manufacturer, All batteries must be installed and used so as to be within the permissible limits defined by the galvanic cell or battery manufacturer, Primary and secondary galvanic cells or batteries must not be used within the same equipment enclosure if they are easily interchangeable, The technical standard EN 60079-0 applies to all electrical equipment and covers factors directly related to the types of protection applied to electrical equipment operating in hazardous areas where the hazard may be caused by gases, vapours, mist, dust, fibres or flammable substances.

When using electrical equipment in installations operating in hazardous areas endangered by potentially explosive atmospheres, care shall be taken also to the selection of such equipment. The correct selection of equipment for use in potentially explosive atmospheres must be considered in the design phase of an installation and verified in the mounting phase. Equipment intended for use in potentially explosive atmospheres must be designed, manufactured and placed on the EU market considering the provisions of the ATEX Directive 2014/34/EU. In order to adequately select the electrical equipment, the provisions of the regulations in force must be considered together with the provisions of applicable standards.

The characteristics providing protection to explosion of equipment designed for use in potentially explosive atmospheres must be preserved during their entire period of life. Repairing is defined as the action to restore faulty equipment to its fully serviceable condition complying with the relevant standard (the standard to which the equipment or parts of equipment were originally designed). Repairing of explosion-proof equipment must be performed considering the prescription of the applicable harmonized standards and the specific type of protection(s) involved. This paper is focused on some particular aspects related to repairing of explosion-proof equipment.

The flameproof enclosure type of protection is still one of the safest because it is based on a very simple and, therefore, unlikely fallible technology. If an explosive atmosphere penetrates an enclosure producing a trigger, the explosion occurs, but it remains confined within the enclosure. EN 60079-1 standard, states that flanged flame paths are allowed in the presence of gases and vapours of Group IIB, but cannot be used with gases and vapours of Group IIC. Also, flame transmission tests for Group IIB equipment are carried out at atmospheric pressure, whereas for Group IIC equipment they are conducted (depending on the testing method applied) at a higher initial pressure. The purpose of the paper is to perform a thorough study upon the differences between testing of flameproof electric motors of Group IIC, compared to electric motors of Group IIB gases and vapours, in terms of testing conditions required by the standard and how the explosion group influences the maximum explosion pressures and explosion pressure development, when tested in explosive mixtures of gases and vapours. The purpose of this paper is to assist manufacturers in designing flameproof electric motors that satisfy the requirements of the specific standard for either Group IIB or Group IIC applications in order to smooth the path for certification.