UL 60079-18
Standard for Explosive Atmospheres - Part 18: Equipment Protection by Encapsulation 'm'

Edition Number:4SCC Approved:--
Edition Date:2015-12-14DOD Approved: --
Price Code:GANSI Approved: 2019-02-07


    1 Scope

    1DV Modification of Clause 1 to replace with the following:

    This part of IEC 60079 standard gives the specific requirements for the construction, testing and marking of electrical equipment, parts of electrical equipment and Ex components with the type of protection encapsulation “m” intended for use in explosive gas atmospheres or explosive dust atmospheres.

    This part standard applies only for encapsulated electrical equipment, encapsulated parts of electrical equipment and encapsulated Ex components (hereinafter always referred to as “m” equipment) where the rated voltage does not exceed 11 kV.

    The application of electrical equipment in atmospheres, which may contain explosive gas as well as combustible dust simultaneously, may require additional protective measures.

    This standard does not apply to dusts of explosives, which do not require atmospheric oxygen for combustion, or to pyrophoric substances.

    This standard does not take account of any risk due to an emission of flammable or toxic gas from the dust.

    This standard supplements and modifies the general requirements of IEC 60079-0. Where a requirement of this standard conflicts with a requirement of IEC 60079-0, the requirement of this standard takes precedence.

    Where references are made to other IEC 60079 standards, the referenced requirements found in these standards shall apply as modified by any applicable U.S. National Differences.

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    • Cover
    • Transmittal
    • Table of Contents
    • UL Preface
    • Deviations
    • IEC Foreword
      • EXPLOSIVE ATMOSPHERES – Part 18: Equipment protection by encapsulation “m”
        • 1 Scope
        • 2 Normative references
        • 3 Terms and definitions
        • 4 General
          • 4.1 Level of protection (equipment protection level (EPL))
          • 4.2 Additional requirements for level of protection “ma” and “mb”
          • 4.3 Additional requirements for level of protection “ma”
          • 4.4 Rated voltage and prospective short circuit current
        • 5 Requirements for compounds
          • 5.1 General
          • 5.2 Specification
          • 5.3 Properties of the compound
        • 6 Temperatures
          • 6.1 General
          • 6.2 Determination of the limiting temperature
          • 6.3 Temperature limitation
        • 7 Constructional requirements
          • 7.1 General
          • 7.2 Determination of faults
          • 7.3 Free space in the encapsulation
          • 7.4 Thickness of the compound
          • 7.5 Switching contacts
          • 7.6 External connections
          • 7.7 Protection of bare live parts
          • 7.8 Cells and batteries
          • 7.9 Protective devices
        • 8 Type tests
          • 8.1 Tests on the compound
          • 8.2 Tests on the apparatus
        • 9 Routine verifications and tests
          • 9.1 Visual inspections
          • 9.2 Dielectric strength test
        • 10 Marking
    • Annex A (informative) Basic requirements for compounds for “m” equipment
    • Annex B(informative)Allocation of test samples
    • Annex C(normative)Dielectric strength test between circuits and environment
    • Bibliography