UL 508
Standard for Industrial Control Equipment

DETAILS
Edition Number:18SCC Approved:--
Edition Date:2018-03-30DOD Approved: 1989-06-05
Price Code:DANSI Approved: 2018-03-30
Type:ulstd

  • SCOPE

    1 Scope

    1.1 These requirements cover industrial control devices, and devices accessory thereto, for starting, stopping, regulating, controlling, or protecting electric motors. These requirements also cover industrial control devices or systems that store or process information and are provided with an output motor control function(s). This equipment is for use in ordinary locations in accordance with the National Electrical Code, NFPA 70. These requirements do not include requirements for the evaluation of equipment intended for use in functional safety applications.

    1.2 These requirements cover devices rated 1500 volts or less. Industrial control equipment covered by these requirements is intended for use in an ambient temperature of 0 – 40°C (32 – 104°F) unless specifically indicated for use in other conditions.

    1.3 Examples of industrial control devices described in 1.1 are:

    a)    Manual, magnetic, and solid-state starters and controllers.

    b)    Thermal, magnetic, and solid-state overload relays.

    c)    Pushbutton stations, including selector switches and pilot lights.

    d)    Control circuit switches and relays.

    e)    Float, flow, pressure, and vacuum-operated switches.

    f)    Resistors and rheostats.

    g)    Proximity switches.

    h)    Time-delay relays and switches.

    i)    Resistors and rheostats intended for industrial heating and lighting, including those for motor generator fields.

    j)    Control devices intended for industrial heating and lighting.

    k)    Solid-state time-delay relays.

    l)    Programmable controllers.

    m)    Numerical control systems.

    n)    Lighting dimmer systems and controls.

    o)    Mercury-tube switches.

    p)    Definite purpose controllers.

    q)    Solid-state logic controllers.

    r)    Industrial microprocessor/computer systems.

    s)    Variable voltage autotransformer.

    t)    Motor starting autotransformer.

    1.4 Industrial control panels are covered by the requirements in the Standard for Industrial Control Panels, UL 508A.

    1.5 Fire pump controllers are covered by the requirements in the Standard for Fire Pump Controllers, UL 218.

    1.6 An adjustable-speed drive and accessories or modules for use with an adjustable-speed drive are covered by the Standard for Power Conversion Equipment, UL 508C.

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

    1.8 Devices that regulate temperature and/or control refrigeration equipment are covered by the Standard for Temperature-Indicating and -Regulating Equipment, UL 873, and other applicable standards. Compliance with the Standard for Automatic Electrical Controls for Household and Similar Use, Part 1: General Requirements, UL 60730-1, and/or the applicable Part 2 standard from the UL 60730 series fulfills these requirements.

    1.9 Electrical instruments are covered by the Standard for Electrical Analog Instruments– Panel Board Types, UL 1437.

    1.10 Products consisting of interlocked controllers and similar assemblies, intended to transfer power to a common load or output between multiple inputs or sources, are covered by the Standard for Transfer Switch Equipment, UL 1008.

  • TABLE OF CONTENTS
    Expand All

    • Cover
    • Transmittal
    • Table of Contents
      • Body
        • Part
          • INTRODUCTION
          • 1 Scope
          • 2 Glossary
          • 3 Units of Measurement
          • 4 Components
          • 5 Undated References
          • 6 Installation and Operation Instructions
        • PART I – ALL EQUIPMENT
          • ENCLOSURE CONSTRUCTION
          • 7 Frames and Enclosure
            • 7.1 General
            • 7.2 Cast metal
            • 7.3 Sheet metal
            • 7.4 Doors and covers
            • 7.5 Polymeric
            • 7.6 Bonding
            • 7.7 Resistance measurement
            • 7.8 Openings in enclosure
            • 7.9 Ventilating openings
            • 7.10 Barriers used with ventilation openings
            • 7.11 Forced ventilation
            • 7.12 Observation windows
            • 7.13 Transformer or autotransformer
            • 7.14 Motor controller wire bending space
            • 7.15 Specific enclosures
            • 7.16 Components for use on specific enclosures
            • 7.17 Accessibility of live parts
          • 8 Protection Against Corrosion
            • 8.1 General
            • 8.2 Outdoor enclosures
          • ENCLOSURE PERFORMANCE
          • 9 General
          • 10 Securement of Snap-On Cover Test
          • INSTRUCTIONS AND MARKINGS PERTAINING TO ENCLOSURES
          • 11 Permanence of Marking
          • 12 Details
          • DEVICE CONSTRUCTION
          • 13 General
          • 14 Protection Against Corrosion
          • 15 Provisions for Mounting
          • 16 Insulating Material
          • 17 Means for Switching
          • 18 Live Parts
          • 19 Protective Devices
            • 19.1 General
            • 19.2 Protection of internal primary and secondary control circuit conductors
            • 19.3 Protection of control circuit transformer
            • 19.4 Low-voltage protection
            • 19.5 Phase loss protection
            • 19.6 Phase-reversal protection
          • 20 Capacitors
          • 21 Fuseholders
          • 22 Internal Wiring
            • 22.1 General
            • 22.2 Routing of internal wiring
            • 22.3 Clamps and guides
            • 22.4 Flexing of internal wiring
            • 22.5 Additional insulation
            • 22.6 Splices and connections
            • 22.7 Splice insulation
          • 23 External Interconnections
            • 23.1 Open equipment
            • 23.2 Enclosed equipment
            • 23.3 Interconnecting cords and cables
          • 24 Transformers
          • 25 Blower Motors
          • 26 Supply Connections
            • 26.1 General
            • 26.2 Permanently connected equipment
            • 26.3 Tapped holes for conduit
            • 26.4 Knockouts
            • 26.5 Size of wiring terminals and leads
            • 26.6 Evaluation of pressure wire connectors
            • 26.7 Evaluation of quick connect terminals
            • 26.8 Evaluation of wire binding screws
            • 26.9 Evaluation of field wiring leads
            • 26.10 Evaluation of spring type terminations
            • 26.11 Cord-connected equipment
          • 27 Cord-Connected Programming and Diagnostic Units
          • 28 Coil Windings
          • 29 Risk of Electric Shock
          • 30 Risk of Fire
          • 31 Lithium Battery Circuits
          • 32 Non-Lithium Battery Circuits
            • 32.1 General
            • 32.2 Primary non-rechargeable
            • 32.3 Secondary rechargeable/non-rechargeable
          • 33 Isolated Secondary Circuits
            • 33.1 General
            • 33.2 Class 2 circuit requirements
            • 33.3 Limited voltage/current circuit requirements
            • 33.4 Limited voltage circuit requirements
            • 33.5 Isolated power supply circuit requirements
            • 33.6 Limited energy circuit requirements
            • 33.7 Limiting impedance circuit requirements
            • 33.8 Limited Power Source circuit requirements
          • 34 Limited Voltage Primary Circuit
          • 35 Separation of Circuits
          • 36 Isolation Devices
          • 37 Spacings
          • 38 Insulating Barriers
          • 39 Clamped Insulating Joints in Lieu of Spacings
          • 40 Clearance and Creepage Distances
          • 41 Protection of Service Personnel
          • 42 Grounding
            • 42.1 General
            • 42.2 Internal insulated bonding, grounding, and grounded circuit conductors
            • 42.3 Transformer secondary grounding
          • 43 Accessories
          • DEVICE PERFORMANCE
          • 44 General
          • 45 Temperature Test
          • 46 Overvoltage and Undervoltage Test
          • 47 Overload Test
          • 48 Endurance Test
          • 49 Endurance Test for Relays for Television Applications
          • 50 Calibration Test
          • 51 Dielectric Voltage-Withstand Test
            • 51.1 General
            • 51.2 Coils
            • 51.3 Secondary circuits
          • 52 Short Circuit Test – General
            • 52.1 General
            • 52.2 Enclosure
            • 52.3 Sample preparation
          • 53 Standard Fault Current Circuits
            • 53.1 Protective devices
            • 53.2 Sample selection for overload relay
            • 53.3 Parameters
          • 54 High-Available Fault Current Circuits (Optional)
            • 54.1 General
            • 54.2 Sample selection
            • 54.3 Procedure
          • 55 Group Installation (Optional)
            • 55.1 General
            • 55.2 Sample selection
            • 55.3 Group installation for standard fault circuit ratings
            • 55.4 Group installation for high capacity short circuit ratings
          • 56 Standard and High Fault Acceptance Criteria
          • 57 Calibration of Test Circuits
            • 57.1 Circuit characteristics
            • 57.2 Alternating-current circuits
            • 57.3 Direct current circuits
            • 57.4 Instrumentation for test currents above 10,000 amperes
            • 57.5 Calibration characteristics for protective device
          • 58 Transient-Voltage-Surge Suppression Test
          • 59 Accelerated Aging Test
          • 60 Breakdown of Components Test
          • 61 Strain Relief Test
          • 62 Push-Back Relief Test
          • 63 Wire Flexing
          • 64 Printed Wiring Board Abnormal Operation Test
          • 65 Secondary Circuits Test
            • 65.1 General
            • 65.2 Limited voltage/current secondary test
            • 65.3 Limited energy secondary test
            • 65.4 Isolated power supply capacity test
            • 65.5 Limited voltage secondary test
            • 65.6 Limiting impedance test
          • 66 Leakage Current Test
          • 67 Protection Against Contact with Live Parts of Door Mounted Components Test
          • 68 Electronic Fluorescent Ballasts
          • DEVICE RATING
          • 69 Details
          • MARKING
          • 70 General
          • 71 Wiring Terminal Markings
          • 72 Cautionary Markings
          • INSTRUCTIONS AND MARKINGS PERTAINING TO ACCESSORIES
          • 73 Details
          • 74 Marking Location
          • MANUFACTURING AND PRODUCTION TESTS
          • 75 Production-Line Dielectric Voltage-Withstand Test
          • 76 Production-Line Grounding-Continuity Test
          • 77 Production-Line Polarization-Continuity Test – Cord and Plug Connected Equipment
        • PART II – MAGNETIC MOTOR CONTROLLERS
          • CONSTRUCTION
          • 78 General
          • PERFORMANCE
          • 79 General
          • RATING
          • 80 Details
          • MARKING
          • 81 Marking
        • PART III – MANUAL MOTOR CONTROLLERS
          • CONSTRUCTION
          • 82 General
          • PERFORMANCE
          • 83 General
          • 84 Temperature Test
          • 85 Endurance Test (Motor Disconnect)
          • 86 Dielectric Voltage Withstand Test
          • 87 Short Circuit Test (Motor Disconnect)
          • 88 Voltage-Withstand Test (Disconnect)
          • 89 Magnetic Trip Out Test
          • 90 Calibration – 200 Percent
          • 91 Short Circuit Tests for Tap Conductor Protection
            • 91.1 Short circuit interrupting ability
            • 91.2 High fault short circuit test
          • RATING
          • 92 Details
          • MARKING
          • 93 Details
        • PART IV – COMBINATION MOTOR CONTROLLERS
          • CONSTRUCTION
          • 94 General
          • PERFORMANCE
          • 95 General
          • 96 Temperature Test
          • 97 Dielectric Voltage Withstand Test
          • 98 Current Withstand Test
          • 99 Contactor Overload Test
          • 100 Voltage-Withstand Test
          • 101 Magnetic Trip-Out Test
          • 102 Combination Short Circuit Test
          • 103 Interrupting Ability (Short Circuit) Test
          • 104 Endurance Test
          • 105 Calibration Test – 200 Percent
          • 106 High Available Short Circuit Current Test
          • 107 Coordination Test
          • RATINGS
          • 108 Details
          • MARKING
          • 109 Details
        • PART V – REDUCED-VOLTAGE STARTERS
          • CONSTRUCTION
          • 110 General
          • PERFORMANCE
          • 111 Operation Test
          • 112 Duty Cycle Test
          • RATINGS
          • 113 Details
          • MARKING
          • 114 Details
        • PART VI – SOLID-STATE AC MOTOR CONTROLLERS
          • CONSTRUCTION
          • 115 General
          • PERFORMANCE
          • 116 General
          • 117 Temperature Test
          • 118 Dielectric Voltage-Withstand Test
          • 119 Overvoltage and Undervoltage Test
          • 120 Overload Test
          • 121 Endurance Test
          • 122 Short Circuit Test
            • 122.1 Evaluation of short circuit test
            • 122.2 Selection of samples
            • 122.3 Test procedure
            • 122.4 Test circuit
          • 123 Breakdown of Components Test
          • 124 Operation Tests
            • 124.1 General
            • 124.2 Controller overload
            • 124.3 Single phasing
            • 124.4 Inoperative blower motor
            • 124.5 Clogged filter
            • 124.6 Current limiting control
          • RATING
          • 125 Details
          • MARKING
          • 126 Details
        • PART VII – FLOAT- AND PRESSURE-OPERATED SWITCHES
          • GENERAL
          • 127 Glossary
          • CONSTRUCTION
          • 128 General
          • 129 Supply Connections – Permanently-Connected Devices
          • 130 Supply Connections – Cord- and Plug-Connected Devices
          • PERFORMANCE
          • 131 General
          • 132 Overload Test
          • 133 Endurance Test
          • 134 Pressure Tests
            • 134.1 General
            • 134.2 Parts contained in an enclosure
            • 134.3 Parts not contained in an enclosure
          • 135 Hub and Nipple Tests
            • 135.1 General
            • 135.2 Pullout
            • 135.3 Bending
            • 135.4 Torque
          • 136 Float SwitchTests
            • 136.1 General
            • 136.2 Immersion
            • 136.3 Dielectric voltage-withstand
            • 136.4 Tensile strength and ultimate elongation
            • 136.5 Insulation resistance test
          • RATING
          • 137 Details
          • MARKING
          • 138 Details
        • PART VIII – SEMICONDUCTOR RELAYS AND SWITCHES
          • CONSTRUCTION
          • 139 General
          • PERFORMANCE
          • 140 General
          • 141 Temperature Test
          • 142 Overvoltage and Undervoltage Test
          • 143 Overload Test
          • 144 Endurance Test
          • 145 Dielectric Voltage-Withstand Test
          • 146 Breakdown of Components Test
          • RATING
          • 147 Details
          • MARKING
          • 148 General
        • PART IX – MERCURY TUBE SWITCHES
          • CONSTRUCTION
          • 149 General
          • PERFORMANCE
          • 150 General
          • 151 Overvoltage and Undervoltage Test
          • 152 Short Circuit Test
          • RATING
          • 153 Details
          • MARKING
          • 154 Details
        • PART X – AUXILIARY DEVICES
          • CONSTRUCTION
          • 155 General
          • PERFORMANCE
          • 156 General
          • 157 Temperature Test
          • 158 Overvoltage and Undervoltage Test
          • 159 Overload Test
          • 160 Endurance Test
          • RATING
          • 161 Details
          • MARKING
          • 162 Details
        • PART XI – MECHANICAL OVERLOAD RELAYS
          • CONSTRUCTION
          • 163 General
          • PERFORMANCE
          • 164 General
          • 165 Overload Test
          • 166 Endurance Test
          • RATING
          • 167 Details
          • MARKING
          • 168 Details
        • PART XII – ELECTRONIC OVERLOAD RELAYS
          • CONSTRUCTION
          • 169 General
          • PERFORMANCE
          • 170 General
          • 171 Short-Circuit Test for Devices Provided with a Current Transformer
          • 172 Short-Circuit Test for Devices Not Provided with a Current Transformer
          • 173 Calibration Test
          • 174 Breakdown of Components Test
          • RATING
          • 175 Details
          • MARKING
          • 176 Details
        • PART XIII – DEFINITE PURPOSE CONTROLLERS
          • CONSTRUCTION
          • 177 General
          • PERFORMANCE
          • 178 General
          • 179 Overvoltage and Undervoltage Test
          • 180 Overload Test
          • 181 Endurance Test
          • 182 Locked Rotor Endurance Test
          • 183 Part Winding Endurance Test
          • 184 Short Circuit Test
          • RATING
          • 185 Details
          • MARKING
          • 186 Details
        • PART XIV – SERVICE EQUIPMENT
          • 187 General
        • PART XV – LAMP DIMMERS
          • CONSTRUCTION
          • 188 General
          • PERFORMANCE
          • 189 General
          • 190 Temperature Test
          • 191 Operation Test
          • 192 Abnormal Operation Test
          • 193 D-C Offset Test
          • RATING
          • 194 Details
          • MARKING
          • 195 Details
        • PART XVI – MISCELLANEOUS DEVICES
          • CONSTRUCTION
          • 196 General
          • PERFORMANCE
          • 197 General
          • 198 Input Test
          • 199 Temperature Test
          • 200 Normal Operation Test
          • 201 Abnormal Operation Test
          • 202 Burnout Test
          • 203 Inoperative Blower Motor Test
          • RATING
          • 204 Details
          • MARKING
          • 205 Details
        • PART XVII – PROGRAMMABLE CONTROLLERS
          • GENERAL
          • 206 Details
          • CONSTRUCTION
          • 207 General
          • 208 Spacings
          • 209 Separation of Circuit Barriers
          • 210 Bonding
          • PERFORMANCE
          • 211 General
          • 212 Temperature Test
          • 213 Overvoltage and Undervoltage Test
          • 214 Overload Test
          • 215 Endurance Test
          • 216 Dielectric Voltage-Withstand Test
          • 217 Breakdown of Components Test
          • 218 Impedance Test
          • RATING
          • 219 Details
          • MARKING
          • 220 Details
          • 221 Signal Circuits
        • PART XVIII – PROXIMITY SWITCHES
          • GENERAL
          • 222 Details
          • 223 Glossary
          • CONSTRUCTION
          • 224 General
          • PERFORMANCE
          • 225 General
          • 226 Lasers, Ultraviolet and Infrared Emissions
          • 227 Power-Supply Cord Tests
            • 227.1 General
            • 227.2 Tensile strength and elongation tests
            • 227.3 Oven conditioning
            • 227.4 Oil conditioning
            • 227.5 Ultraviolet light (UV) conditioning
            • 227.6 Cold bend test
          • 228 Cable Gland Connector Tests
            • 228.1 General
            • 228.2 Oven conditioning (rubber composition)
            • 228.3 Oven conditioning (thermoplastic composition)
            • 228.4 Flexing test
            • 228.5 Strain relief test
          • 229 Strain Relief Test
          • 230 Tests for Environmental Type Enclosures
          • RATING
          • 231 Details
          • MARKING
          • 232 Details
    • INDUSTRIAL CONTROL EQUIPMENT FOR MARINE USE
    • APPENDIX A
    • INDEX