IEEE DRAFT C37.20.3 : 2001

1 Scope
2 References
3 Definitions
   3.1 Switchgear
        3.1.1 Switchgear assemblies
        3.1.2 Metal-enclosed power switchgear
        3.1.3 Metal-enclosed interrupter switchgear
   3.2 Qualifying terms
   3.3 Common or related terms
   3.4 Ambient air temperature
   3.5 Design test
   3.6 Production test
   3.7 Conformance test
   3.8 Field test
   3.9 Switch compartment
   3.10 Vertical section
4 Service conditions
5 Ratings
   5.1 General
   5.2 Voltage and insulation levels
        5.2.1 Rated maximum voltage
        5.2.2 Rated insulation levels
        5.2.3 Preferred values for voltage and insulation levels
   5.3 Rated power frequency
   5.4 Rated currents
        5.4.1 Rated continuous current
        5.4.2 Continuous current ratings
        5.4.3 Rated momentary withstand current
        5.4.4 Momentary current withstand ratings
        5.4.5 Rated short-term withstand current
   5.5 Temperature limitations
        5.5.1 Limiting temperatures
        5.5.2 Temperature limits for insulating materials
        5.5.3 Temperature limitations for buses and connections
        5.5.4 Temperature limitations for air surrounding devices
               within an enclosed assembly
        5.5.5 Temperature limitations for air surrounding insulated
               power cables
        5.5.6 Temperature limitations for external parts subject to
               contact by personnel
   5.6 Current transformer ratings
        5.6.1 Current transformer mechanical ratings
        5.6.2 Current transformer thermal ratings
        5.6.3 Current transformer ambient temperature
6 Test
   6.1 General
   6.2 Design test
        6.2.1 Dielectric test
        6.2.2 Continuous current test
        6.2.3 Short-time withstand current test
        6.2.4 Momentary withstand current test
        6.2.5 Mechanical endurance test
        6.2.6 Sheet, moulded, or cast-insulating materials for
               support of primary bus and connections
        6.2.7 Bus-bar insulation
        6.2.8 Paint qualification test
        6.2.9 Rain test for outdoor MEI switchgear
   6.3 Production tests
        6.3.1 Dielectric test
        6.3.2 Mechanical operation test
        6.3.3 Grounding of instrument transformer case test
        6.3.4 Electrical operation and control wiring test
   6.4 Conformance tests
   6.5 Field test
7 Construction
   7.1 General requirements
        7.1.1 Buses and primary connections
        7.1.2 Grounding
        7.1.3 Control and secondary circuits and devices
        7.1.4 Miscellaneous
   7.2 Materials and finish
        7.2.1 Materials
        7.2.2 Finishes and colors
   7.3 Barriers
   7.4 Buses and connections
   7.5 Interlocks
   7.6 Indoor MEI switchgear, access and ventilation
   7.7 Outdoor MEI switchgear, access and ventilation
   7.8 Shutters
   7.9 Precautionary labels
   7.10 Enclosure categories
8 Application guide for MEI switchgear
   8.1 Unusual service conditions
        8.1.1 Ambient air temperature above 40 degree C
        8.1.2 Ambient air temperature below -30 degree C
        8.1.3 Application at unusual altitudes
        8.1.4 Modification of equipment for unusual environment
   8.2 System characteristics - voltage and frequency
   8.3 Overvoltage considerations - insulation levels
   8.4 Continuous current rating and overload capability
        8.4.1 Conductor temperature
        8.4.2 Conductor terminations
   8.5 Short-circuit considerations
   8.6 Nuclear power plant application
   8.7 Exposed circuits
   8.8 Surge arresters in switchgear assemblies
   8.9 Protection and isolation of switchgear connected to
        other switching equipment
   8.10 Current transformers accuracies
9 Guide for handling, storage and installation
   9.1 General
   9.2 Handling
   9.3 Preoperation check
   9.4 Interrupter switches
   9.5 Interlocks
   9.6 Energization
Annex A Guide for enclosure categories and related requirements
         A.1 Scope
         A.2 Enclosure categories
              A.2.1 Category A enclosures
              A.2.2 Category B enclosures
              A.2.3 Category C enclosures
         A.3 Enclosure requirements
              A.3.1 Construction
              A.3.2 Painting and corrosion/protection
              A.3.3 Materials
              A.3.4 Framework
              A.3.5 Equivalent construction
              A.3.6 Access doors and covers
              A.3.7 Enclosure ventilation openings
              A.3.8 Operating handle protection
              A.3.9 Operating handles
              A.3.10 Viewing panes
              A.3.11 Accessories
              A.3.12 Outdoor enclosure requirements
              A.3.13 Exposed live parts
              A.3.14 External marking

Covers metal enclosed interrupter switchgear assemblies containing, but not limited to such devices as selector switches, power fuses, instrumentation and metering, control interrupter/switches and protective equipment. Included but not limited to, equipment for the protection and control of apparatus used in the distribution of electrical power. Covers enclosed rather than open switchgear assemblies over 1000v. Equipment included forms part of secondary and primary unit substations. Equipment not included are gas-insulated substations, or integrally mounted switching devices within transformer enclosures.