This part of IEC60079 specifies general and testing requirements for electrical resistance trace heaters for application in explosive atmospheres with the exclusion of those for EPL Ga and Da. This standard covers trace heaters that comprise either factory or field (work-site) assembled units, and which may be series trace heaters, parallel trace heaters, trace heater pads, or trace heater panels that have been assembled and/or terminated in accordance with the manufacturer’s instructions. This standard also includes requirements for termination assemblies and control methods used with trace heating systems. The explosive atmospheres referred to in this standard are those defined in IEC60079-10-1 and IEC60079-10-2 . Text deleted This standard supplements and modifies the general requirements of IEC60079-0 , except as indicated in Table1. Where a requirement of this standard conflicts with a requirement of IEC60079-0 , the requirement of this standard takes precedence. Table1 Application or exclusion of specific clauses of IEC60079-0 IEC60079-0 Electrical resistance trace heaters and integral components Terminations as separate components Ed. 6.0 (2011) (informative) Clause/Subclause title (normative) Group I and Group II Group III 1 Scope Applies Applies Applies 2 Normative references Applies Applies Applies 3 Terms and definitions Applies, except ambient temperature, see 3.1 Applies, except ambient temperature, see 3.1 Applies, except ambient temperature, see 3.1 4 Equipment grouping Applies Applies Applies 4.1 Group I Applies Excluded Applies 4.2 Group II Applies, always IIC Excluded Applies 4.3 Group III Excluded Applies, outside of thermal insulation only, always IIIC Applies, outside of thermal insulation only 4.4 Equipment for a particular explosive atmosphere Excluded Excluded Applies 5.1 Environmental influences Applies Applies Applies 5.1.1 Ambient temperature Replaced by 6.1e) Replaced by 6.1e) Applies, see 3.1 5.1.2 External source of heating or cooling Applies Applies Applies 5.2 Service temperature Modified Modified Applies 5.3.1 Determination of maximum surface temperature Replaced by 4.5 in conjunction with 5.1.13 Replaced by 4.5 in conjunction with 5.1.13 only when tested in accordance with 5.1.13.3. Applies 5.3.2.1 Group I electrical equipment Applies Excluded Applies 5.3.2.2 Group II electrical equipment Applies Excluded Applies 5.3.2.3.1 Group III electrical equipment, Maximum surface temperature determined without a dust layer Excluded Applies, where the maximum sheath temperatures determined by IEC/IEEE60079-30-1 are used in place of the method for temperature determination from IEC60079-0 . Applies 5.3.2.3.2 Group III electrical equipment Maximum surface temperature with respect to dust layers Excluded Applies, where the maximum sheath temperature is determined only for those surfaces that are specified to be exposed to layers of combustible dust. Does not apply for trace heaters specified to be covered by thermal insulation. Applies 5.3.3 Small component temperature for Group I and Group II electrical equipment Excluded Excluded Applies 6.1 Requirements for all electrical equipment— General Applies Applies Applies 6.2 Mechanical strength Replaced by 4.2 Replaced by 4.2 When in direct contact with the trace heater, may be substituted by 4.2 6.3 Opening times Excluded Excluded Applies 6.4 Circulating currents in enclosures (e.g. of large electrical machines) Excluded Excluded Excluded 6.5 Gasket retention Excluded Excluded Applies 6.6 Electromagnetic and ultrasonic radiating equipment Excluded Excluded Applies 7.1.1 Non-metallic enclosures and non-metallic parts of enclosures— Applicability Replaced by the last paragraph of 4.1 Replaced by the last paragraph of 4.1 Applies 7.1.2.1 Specification of materials, General Replaced by the last paragraph of 4.1 Replaced by the last paragraph of 4.1 Applies 7.1.2.2 Specification of materials, plastic materials Replaced by the last paragraph of 4.1 Replaced by the last paragraph of 4.1 Applies 7.1.2.3 Elastomers Replaced by the last paragraph of 4.1 Replaced by the last paragraph of 4.1 Applies 7.2 Thermal endurance Replaced by requirements and tests Replaced by requirements and Applies of this standard tests of this standard 7.3 Resistance to light Replaced by 5.1.16 for trace heaters and integral components specified for outdoor exposure Replaced by 5.1.16 for trace heaters and integral components specified for outdoor exposure Applies 7.4.1 Electrostatic charges on external non-metallic materials, Applicability Excluded Excluded Applies 7.4.2 Avoidance of a build-up of electrostatic charge on Group I or Group II electrical equipment Excluded Excluded Applies 7.4.3 Avoidance of a build-up of electrostatic charge on equipment for Group III Excluded Excluded Applies 7.5 Accessible metal parts Excluded Excluded Applies 8.1 Material composition Excluded Excluded Applies 8.2 Group I Excluded Excluded Applies 8.3 Group II Excluded Excluded Applies 8.4 Group III Excluded Excluded Applies 9 Fasteners Excluded Excluded Applies 10 Interlocking devices Excluded Excluded Applies 11 Bushings Excluded Excluded Applies 12 Materials used for cementing Replaced by the last paragraph of 4.1 Replaced by the last paragraph of 4.1 Applies 13 Ex Components Applies Applies Applies 14 Connection facilities and termination compartments Covered by the requirements of this standard Covered by the requirements of this standard Applies 15 Connection facilities for earthing and bonding conductors Replaced by 5.1.15 Replaced by 5.1.15 Applies 15 Entries into enclosures Excluded Excluded Applies 17 Supplementary requirements for rotating electrical machines Excluded Excluded Excluded 18 Supplementary requirements for switchgear Excluded Excluded Excluded 19 Supplementary requirements for fuses Excluded Excluded Applies 20 Supplementary requirements for plugs and sockets Excluded Excluded Applies 21 Supplementary requirements for luminaires Excluded Excluded Excluded 22 Supplementary requirements for caplights and handlights Excluded Excluded Excluded 23 Equipment incorporating cells and batteries Excluded Excluded Applies 24 Documentation Applies Applies Applies 25 Compliance of prototype or Applies Applies Applies sample with documents 26.1 General Applies Applies Applies 26.2 Test configuration Applies Applies. Applies 26.3 Tests in explosive test mixtures Excluded Excluded Applies 26.4 Tests of enclosures Excluded Excluded Applies 26.4.1 Order of tests Excluded Excluded Applies 26.4.1.1 Metallic enclosures, metallic parts of enclosures and glass parts of enclosures Excluded Excluded Applies 26.4.1.2 Non-metallic enclosures or non-metallic parts of enclosures Excluded Excluded Applies 26.4.2 Resistance to impact Replaced by 5.1.5 Replaced by 5.1.5 Applies 26.4.3 Drop test Excluded Excluded Excluded 26.4.4 Acceptance criteria Replaced by 5.1.5 Replaced by 5.1.5 Applies 26.4.5 Degree of protection by enclosure Replaced by 5.1.8 and/or 5.1.9 Replaced by 5.1.8 and/or 5.1.9. Applies 26.5 Thermal tests Modified. Modified Applies 26.5.1 Temperature measurement Replaced by 5.1.13 Replaced by 5.1.13 Applies 26.5.2 Thermal shock test Excluded Excluded Applies 26.5.3 Small component ignition test Excluded Excluded Applies 26.6 Torque test for bushings Excluded Excluded Applies 26.7 Non-metallic enclosures or non-metallic parts of enclosures Excluded Excluded Applies 26.8 Thermal endurance to heat Replaced by 5.1.11 Replaced by 5.1.11 Applies 26.9 Thermal endurance to cold Replaced by 5.1.7 Replaced by 5.1.7 Applies 26.10 Resistance to light Replaced by 5.1.16for trace heaters and integral components specified for outdoor exposure Replaced by 5.1.16 for trace heaters and integral components specified for outdoor exposure Applies 26.11 Resistance to chemical agents for Group I electrical equipment Applies for Group I Excluded Applies 26.12 Earth continuity Excluded Excluded Applies 26.13 Surface resistance test of parts of enclosures of non-metallic materials Excluded Excluded Applies 26.14 Measurement of capacitance Excluded Excluded Applies 26.15 Verification of ratings of ventilating fans Excluded Excluded Excluded 26.16 Alternative qualification of elastomeric sealing O-rings Excluded Excluded Applies 27 Routine tests Applies Applies Applies 28 Manufacturers responsibility Applies Applies Applies 29 Marking Modified Modified Applies 30 Instructions Modified Modified Applies AnnexA Supplementary requirements for Ex cable glands Excluded Excluded Applies AnnexB Requirements for Ex components Excluded Excluded Applies AnnexC Example of rig for resistance to impact test Replaced by 5.1.5 Replaced by 5.1.5 Applies AnnexD Motors supplied by converters Excluded Excluded Excluded AnnexE Temperature rise testing of electric machines Excluded Excluded Excluded AnnexE Guideline flowchart for tests of non-metallic enclosures or non-metallic parts of enclosures (26.4) Excluded Excluded Applies NOTE1 Clause numbers in the three right-hand columns of this table refer to IEC/IEEE60079-30-1 NOTE2 The clause number in the above table is shown for information only. The applicable requirements of IEC60079-0 are identified by the clause title which is normative. Applies: this requirement of IEC60079-0 is applied without change. Excluded: this requirement of IEC60079-0 does not apply. Modified: this requirement of IEC60079-0 is modified as detailed in this standard.