UL 508C
Standard for Power Conversion Equipment

DETAILS
Edition Number:4SCC Approved:--
Edition Date:2016-05-16DOD Approved: --
Price Code:BANSI Approved: 2016-05-16
Type:ulstd

  • SCOPE

    1 Scope

    1.1 These requirements cover open or enclosed equipment that supplies power to control a motor or motors operating at a frequency or voltage different than that of the input supply. These requirements also cover power-supply modules, input/output modules, Silicon Controlled Rectifier (SCR) or Transistor output modules, dynamic braking units, and input/output accessory kits for use with power conversion equipment.

    1.2 This equipment is for use in ordinary locations in accordance with Articles 430 and 440 of the National Electrical Code, NFPA 70.

    1.3 These requirements cover devices rated 1500 volts or less.

    1.4 Equipment intended for use in hazardous locations as defined by the National Electrical Code, NFPA 70, shall be evaluated to the Standard for Explosion-Proof and Dust-Ignition-Proof Electrical Equipment for Use in Hazardous (Classified) Locations, UL 1203.

  • TABLE OF CONTENTS
    Expand All

    • Cover
    • Transmittal
    • Table of Contents
      • Body
        • INTRODUCTION
          • 1 Scope
          • 2 Glossary
          • 3 Units of Measurement
          • 4 Components
          • 5 Undated References
        • ENCLOSURE CONSTRUCTION
          • 6 Frames and Enclosure
            • 6.1 General
            • 6.2 Cast metal
            • 6.3 Sheet metal
            • 6.4 Doors and covers
            • 6.5 Polymeric
            • 6.6 Bonding
            • 6.7 Resistance measurement
            • 6.8 Openings in enclosure
            • 6.9 Accessibility of live parts
            • 6.10 Ventilating openings
            • 6.11 Forced ventilation
            • 6.12 Observation windows
            • 6.13 Wire bending space
        • ENVIRONMENTAL RATING RELATED ENCLOSURE CONSTRUCTION
          • 7 General
          • 8 Protection Against Corrosion
        • ENVIRONMENTAL RATING RELATED ENCLOSURE PERFORMANCE
          • 9 General
        • NON-ENVIRONMENTAL RATING RELATED ENCLOSURE PERFORMANCE
          • 10 General
          • 11 Securement of Snap-On Cover Test
        • INSTRUCTIONS AND MARKINGS PERTAINING TO ENCLOSURES
          • 12 Permanence of Marking
          • 13 Details
        • DEVICE CONSTRUCTION
          • 14 General
          • 15 Protection Against Corrosion
          • 16 Provisions for Mounting
          • 17 Insulating Material
          • 18 Means for Switching
          • 19 Live Parts
          • 20 Drive Protection
            • 20.1 General
            • 20.2 Control circuit wiring
            • 20.3 Control circuit transformer
            • 20.4 Control circuit wiring and transformer combination
          • 21 Capacitors
          • 22 Fuseholders
          • 23 Internal Wiring
            • 23.1 General
            • 23.2 Routing
            • 23.3 Flexing
            • 23.4 Color coding
            • 23.5 Splices and connections
            • 23.6 Splice insulation
          • 24 External Interconnections
            • 24.1 Open equipment
            • 24.2 Enclosed equipment
            • 24.3 Interconnecting cords and cables
          • 25 Transformers
          • 26 Blower Motors
          • 27 Supply Connections
            • 27.1 General
            • 27.2 Permanently connected equipment
            • 27.3 Tapped holes for conduit
            • 27.4 Knockouts
            • 27.5 Wiring terminals and leads
            • 27.6 Cord-connected equipment
          • 28 Cord-Connected Programming and Diagnostic Units
          • 29 Risk of Electric Shock
          • 30 Risk of Fire
          • 31 Lithium Battery Circuits
          • 32 Isolated Secondary Circuits
            • 32.1 General
            • 32.2 Class 2 circuits
            • 32.3 Limited voltage/current circuits
            • 32.4 Limited voltage circuits
            • 32.5 Isolated power supply circuits
            • 32.6 Limited energy circuits
            • 32.7 Limiting impedance circuits
          • 33 Limited Voltage Circuit Overcurrent Protection
            • 33.1 General
            • 33.2 Primary overcurrent protection
            • 33.3 Secondary overcurrent protection
          • 34 Separation of Circuits
          • 35 Isolation Devices
          • 36 Spacings
            • 36.1 General
            • 36.2 Spacings other than at field-wiring terminals
            • 36.3 Spacings at field-wiring terminals for pollution degree 2 environments
            • 36.4 Spacings for drives having general ratings for pollution degree 2 environments
            • 36.5 Spacings for drives having limited ratings
            • 36.6 Spacings for drives having other ratings
            • 36.7 Spacings for products with known and controlled transient voltages
            • 36.8 Spacings for drives used in pollution degree 2 environments
            • 36.9 Spacings for drives evaluated in accordance with UL 840
            • 36.10 Testing in lieu of spacings
            • 36.11 Insulating material used as a barrier in lieu of spacings
            • 36.12 Clamped insulating joints in lieu of spacings
            • 36.13 Spacings between live parts and conduit openings
          • 37 Grounding
          • 38 Accessories
        • DEVICE PERFORMANCE
          • 39 General
          • 40 Temperature Test
          • 41 Abnormal Operation Tests
            • 41.1 General
            • 41.2 Contactor overload
            • 41.3 Single phasing
            • 41.4 Inoperative blower motor
            • 41.5 Clogged filter
            • 41.6 Current limiting control
          • 42 Full-Load Motor-Running Current Tables
          • 43 Solid State Motor Overload Protection Test
            • 43.1 General requirements
            • 43.2 Test set-up
            • 43.3 Thermal memory retention test (shutdown)
            • 43.4 Thermal memory retention test (loss of power)
            • 43.5 Speed sensitivity test
          • 44 Dielectric Voltage-Withstand Test
            • 44.1 General
            • 44.2 Clamped joints
          • 45 Short Circuit Test – Standard Fault Currents
            • 45.1 General
            • 45.2 Test circuit current/voltage
            • 45.3 Input/output wiring connection
            • 45.4 Ground fuse
            • 45.5 Enclosures
            • 45.6 Mounting
            • 45.7 Openings
            • 45.8 Branch circuit short circuit protection
          • 46 Group Installation (Optional)
            • 46.1 General
            • 46.2 Sample selection
            • 46.3 Short circuit test – group installation for standard fault currents
            • 46.4 Short circuit test – group installation for high fault currents
          • 47 Calibration of Short Circuit Test Circuits.
            • 47.1 10,000 amperes or less
            • 47.2 More than 10,000 amperes
          • 48 Short Circuit Test – High Fault Currents
          • 49 Transient-Voltage-Surge Suppression Test
          • 50 Accelerated Aging Test
          • 51 Breakdown of Components Test
          • 52 Breakdown of Components Test – Group Installation for Standard Fault Currents
          • 53 Breakdown of Components Test – Group Installation for High Fault Currents
          • 54 Printed Wiring Board Abnormal Operation Test
          • 55 Secondary Circuits Test
            • 55.1 General
            • 55.2 Limited voltage/current secondary test
            • 55.3 Limited energy secondary test
            • 55.4 Isolated power supply capacity test
            • 55.5 Limited voltage secondary test
            • 55.6 Limiting impedance test
          • 56 Strain Relief Test
          • 57 Push-Back Relief Test
          • 58 Leakage Current Test
          • 59 Rating
        • DEVICE MARKING
          • 60 General
          • 61 Overload, Over-Current, and Over-Speed Protection
          • 62 Branch Circuit Short Circuit Protection
          • 63 Branch Circuit Short Circuit Protection for Group Installation
          • 64 Control Circuit Protection
          • 65 Class 2 Circuit Markings
          • 66 Wiring Terminal Markings
          • 67 Cautionary Markings
          • 68 Instructions and Markings Pertaining to Accessories
          • 69 Marking Location
        • MANUFACTURING AND PRODUCTION LINE TEST
          • 70 Circuit Functionality Evaluation
          • 71 Production-Line Dielectric Voltage-Withstand Test
          • 72 Production-Line Grounding-Continuity Test
          • 73 Production-Line Polarization-Continuity Test – Cord and Plug Connected Equipment
        • COOLING SYSTEMS
          • 74 General
          • 75 Construction
          • 76 Performance
            • 76.1 Loss of cooling medium circulation test
            • 76.2 Hydrostatic pressure test
          • 77 Plenum Rated Drives
    • APPENDIX A