UL 508
Standard for Industrial Control Equipment

DETAILS
Edition Number:17SCC Approved:--
Edition Date:1999-01-28DOD Approved: 1989-06-05
Price Code:DANSI Approved: 2013-03-15
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 .

    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 Deleted December 2, 2003

    1.4 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.

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


    1.5 revised December 2, 2003

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


    1.6 revised December 2, 2003

    1.7 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 .

    1.8 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 revised October 16, 2013

    1.9 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 revised October 16, 2013

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

    1.11 A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of fire or of electric shock or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conflict with specific requirements or provisions of this standard does not comply with this standard. Revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard.


    1.11 revised August 22, 2000

    1.12 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.


    1.12 added September 19, 2008

  • TABLE OF CONTENTS
    Expand All

    • Cover
    • Transmittal
    • Table of Contents
    • UL Foreword
      • Body
        • Part
          • INTRODUCTION
          • 1 Scope
          • 2 Glossary
          • 3 Units of Measurement
          • 4 Components
          • 4A Undated ReferencesSection 4A added March 15, 2013
          • 5 Installation and Operation Instructions
        • PART I – ALL EQUIPMENT
          • 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 Ventilating openings
            • 6.10 Barriers used with ventilation openings
            • 6.11 Forced ventilation
            • 6.12 Observation windows
            • 6.13 Transformer or autotransformer
            • 6.14 Motor controller wire bending space
            • 6.15 Specific enclosures
            • 6.16 Components for use on specific enclosures
            • 6.17 Accessibility of live parts
          • 7 Protection Against Corrosion
            • 7.1 General
            • 7.2 Outdoor enclosures
          • ENCLOSURE PERFORMANCE
          • 8 General
          • 9 Securement of Snap-On Cover Test
          • INSTRUCTIONS AND MARKINGS PERTAINING TO ENCLOSURES
          • 10 Permanence of Marking
          • 11 Details
          • DEVICE CONSTRUCTION
          • 12 General
          • 13 Protection Against Corrosion
          • 14 Provisions for Mounting
          • 15 Insulating Material
          • 16 Means for Switching
          • 17 Live Parts
          • 18 Protective Devices
            • 18.1 General
            • 18.2 Protection of internal primary and secondary control circuit conductors
            • 18.3 Protection of control circuit transformer
            • 18.4 Low-voltage protection
            • 18.5 Phase loss protectionSection 18.5 Revised March 15, 2013
            • 18.6 Phase-reversal protection
          • 19 Capacitors
          • 20 Fuseholders
          • 21 Internal Wiring
            • 21.1 General
            • 21.2 Routing of internal wiring
            • 21.3 Clamps and guides
            • 21.4 Flexing of internal wiring
            • 21.5 Additional insulation
            • 21.6 Splices and connections
            • 21.7 Splice insulation
          • 22 External Interconnections
            • 22.1 Open equipment
            • 22.2 Enclosed equipment
            • 22.3 Interconnecting cords and cables
          • 23 Transformers
          • 24 Blower Motors
          • 25 Supply Connections
            • 25.1 General
            • 25.2 Permanently connected equipment
            • 25.3 Tapped holes for conduit
            • 25.4 Knockouts
            • 25.5 Size of wiring terminals and leads
            • 25.5A Evaluation of pressure wire connectors
            • 25.5B Evaluation of quick connect terminals
            • 25.5C Evaluation of wire binding screws
            • 25.5D Evaluation of field wiring leads
            • 25.5E Evaluation of spring type terminations
            • 25.6 Cord-connected equipment
          • 26 Cord-Connected Programming and Diagnostic Units
          • 27 Coil Windings
          • 28 Risk of Electric Shock
          • 29 Risk of Fire
          • 30 Lithium Battery Circuits
          • 31 Non-Lithium Battery Circuits
            • 31.1 General
            • 31.2 Primary non-rechargeable
            • 31.3 Secondary rechargeable/non-rechargeable
          • 32 Isolated Secondary Circuits
            • 32.1 General
            • 32.2 Differences between the level of evaluation required within each type of secondary circuit
            • 32.3 Class 2 circuit requirements
            • 32.4 Limited voltage/current circuit requirements
            • 32.5 Limited voltage circuit requirements
            • 32.6 Isolated power supply circuit requirements
            • 32.7 Limited energy circuit requirements
            • 32.8 Limiting impedance circuit requirements
          • 33 Limited Voltage Primary Circuit
            • 33.1 General
            • 33.2 Overcurrent protection– primary circuits
            • 33.3 Overcurrent protection – secondary circuits
          • 34 Separation of Circuits
          • 35 Isolation Devices
          • 36 Spacings
          • 37 Insulating Barriers
          • 38 Clamped Insulating Joints in Lieu of Spacings
          • 39 Clearance and Creepage Distances
          • 39A Protection of Service Personnel
          • 40 Grounding
            • 40.1 General
            • 40.2 Internal insulated bonding, grounding, and grounded circuit conductors
            • 40.3 Transformer secondary grounding
          • 41 Accessories
          • DEVICE PERFORMANCE
          • 42 General
          • 43 Temperature Test
          • 44 Overvoltage and Undervoltage Test
          • 45 Overload Test
          • 46 Endurance Test
          • 47 Endurance Test for Relays for Television Applications
          • 48 Calibration Test
          • 49 Dielectric Voltage-Withstand Test
            • 49.1 General
            • 49.2 Coils
            • 49.3 Secondary circuits
          • 50 Short Circuit Test – General
            • 50.1 General
            • 50.2 Enclosure
            • 50.3 Sample preparation
            • 50.4 Group fusing
          • 51 Standard Fault Current Circuits
            • 51.1 Protective devices
            • 51.2 Sample selection for overload relay
            • 51.3 Parameters
          • 52 High-Available Fault Current Circuits (Optional)
            • 52.1 General
            • 52.2 Sample selection
            • 52.3 Procedure
          • 52A Group Installation (Optional)
            • 52A.1 General
            • 52A.2 Sample selection
            • 52A.3 Group installation for standard fault circuit ratings
            • 52A.4 Group installation for high capacity short circuit ratings
          • 53 Standard and High Fault Acceptance Criteria
          • 54 Calibration of Test Circuits
            • 54.1 Circuit characteristics
            • 54.2 Alternating-current circuits
            • 54.3 Direct current circuits
            • 54.4 Instrumentation for test currents above 10,000 amperes
            • 54.5 Calibration characteristics for protective device
          • 55 Transient-Voltage-Surge Suppression Test
          • 56 Accelerated Aging Test
          • 57 Breakdown of Components Test
          • 57A Strain Relief Test
          • 57B Push-Back Relief Test
          • 58 Wire Flexing
          • 59 Terminal Torque Test
          • 60 Printed Wiring Board Abnormal Operation Test
          • 61 Secondary Circuits Test
            • 61.1 General
            • 61.2 Limited voltage/current secondary test
            • 61.3 Limited energy secondary test
            • 61.4 Isolated power supply capacity test
            • 61.5 Limited voltage secondary test
            • 61.6 Limiting impedance test
          • 61A Leakage Current Test
          • 61B Protection Against Contact with Live Parts of Door Mounted Components Test
          • 61C Electronic Fluorescent Ballasts
          • DEVICE RATING
          • 62 Details
          • MARKING
          • 63 General
          • 64 Wiring Terminal Markings
          • 65 Cautionary Markings
          • INSTRUCTIONS AND MARKINGS PERTAINING TO ACCESSORIES
          • 66 Details
          • 67 Marking Location
          • MANUFACTURING AND PRODUCTION TESTS
          • 67A Production-Line Dielectric Voltage-Withstand Test
          • 67B Production-Line Grounding-Continuity Test
          • 67C Production-Line Polarization-Continuity Test – Cord and Plug Connected Equipment
        • PART II – MAGNETIC MOTOR CONTROLLERS
          • CONSTRUCTION
          • 68 General
          • PERFORMANCE
          • 69 General
          • RATING
          • 70 Details
          • MARKING
          • 71 Marking
        • PART III – MANUAL MOTOR CONTROLLERS
          • CONSTRUCTION
          • 72 General
          • PERFORMANCE
          • 73 General
          • 73A Temperature Test
          • 73B Endurance Test (Motor Disconnect)
          • 73C Dielectric Voltage Withstand Test
          • 73D Short Circuit Test (Motor Disconnect)
          • 73E Voltage-Withstand Test (Disconnect)
          • 73F Magnetic Trip Out Test
          • 73G Calibration – 200 Percent
          • 73H Short Circuit Tests for Tap Conductor Protection
            • 73H.1 Short circuit interrupting ability
            • 73H.2 High fault short circuit test
          • RATING
          • 74 Details
          • MARKING
          • 75 Details
        • PART IV – COMBINATION MOTOR CONTROLLERS
          • CONSTRUCTION
          • 76 General
          • PERFORMANCE
          • 77 General
          • 77A Temperature Test
          • 77B Dielectric Voltage Withstand Test
          • 78 Current Withstand Test
          • 79 Contactor Overload Test
          • 80 Voltage-Withstand Test
          • 81 Magnetic Trip-Out Test
          • 82 Combination Short Circuit Test
          • 82A Interrupting Ability (Short Circuit) Test
          • 83 Endurance Test
          • 84 Calibration Test – 200 Percent
          • 85 High Available Short Circuit Current Test
          • 86 Coordination Test
          • RATINGS
          • 87 Details
          • MARKING
          • 88 Details
        • PART V – REDUCED-VOLTAGE STARTERS
          • CONSTRUCTION
          • 89 General
          • PERFORMANCE
          • 90 Operation Test
          • 91 Duty Cycle Test
          • RATINGS
          • 92 Details
          • MARKING
          • 93 Details
        • PART VI – SOLID-STATE AC MOTOR CONTROLLERS
          • CONSTRUCTION
          • 94 General
          • PERFORMANCE
          • 95 General
          • 96 Temperature Test
          • 97 Dielectric Voltage-Withstand Test
          • 98 Overvoltage and Undervoltage Test
          • 99 Overload Test
          • 100 Endurance Test
          • 101 Short Circuit Test
            • 101.1 Evaluation of short circuit test
            • 101.2 Selection of samples
            • 101.3 Test procedure
            • 101.4 Test circuit
          • 102 Breakdown of Components Test
          • 103 Operation Tests
            • 103.1 General
            • 103.2 Controller overload
            • 103.3 Single phasing
            • 103.4 Inoperative blower motor
            • 103.5 Clogged filter
            • 103.6 Current limiting control
          • RATING
          • 104 Details
          • MARKING
          • 105 Details
        • PART VII – FLOAT- AND PRESSURE-OPERATED SWITCHES
          • GENERAL
          • 105A Glossary
          • CONSTRUCTION
          • 106 General
          • 107 Supply Connections – Permanently-Connected Devices
          • 108 Supply Connections – Cord- and Plug-Connected Devices
          • PERFORMANCE
          • 109 General
          • 110 Overload Test
          • 111 Endurance Test
          • 112 Pressure Tests
            • 112.1 General
            • 112.2 Parts contained in an enclosure
            • 112.3 Parts not contained in an enclosure
          • 113 Hub and Nipple Tests
            • 113.1 General
            • 113.2 Pullout
            • 113.3 Bending
            • 113.4 Torque
          • 114 Float SwitchTests
            • 114.1 General
            • 114.2 Immersion
            • 114.3 Dielectric voltage-withstand
            • 114.4 Tensile strength and ultimate elongation
            • 114.5 Insulation resistance test
          • RATING
          • 115 Details
          • MARKING
          • 116 Details
        • PART VIII – SEMICONDUCTOR RELAYS AND SWITCHES
          • CONSTRUCTION
          • 117 General
          • PERFORMANCE
          • 118 General
          • 119 Temperature Test
          • 120 Overvoltage and Undervoltage Test
          • 121 Overload Test
          • 122 Endurance Test
          • 123 Dielectric Voltage-Withstand Test
          • 124 Breakdown of Components Test
          • RATING
          • 125 Details
          • MARKING
          • 126 General
        • PART IX – MERCURY TUBE SWITCHES
          • CONSTRUCTION
          • 127 General
          • PERFORMANCE
          • 128 General
          • 129 Overvoltage and Undervoltage Test
          • 130 Short Circuit Test
          • RATING
          • 131 Details
          • MARKING
          • 132 Details
        • PART X – AUXILIARY DEVICES
          • CONSTRUCTION
          • 133 General
          • PERFORMANCE
          • 134 General
          • 135 Temperature Test
          • 136 Overvoltage and Undervoltage Test
          • 137 Overload Test
          • 138 Endurance Test
          • RATING
          • 139 Details
          • MARKING
          • 140 Details
        • PART XI – MECHANICAL OVERLOAD RELAYS
          • CONSTRUCTION
          • 141 General
          • PERFORMANCE
          • 142 General
          • 143 Overload Test
          • 144 Endurance Test
          • RATING
          • 145 Details
          • MARKING
          • 146 Details
        • PART XII – ELECTRONIC OVERLOAD RELAYS
          • CONSTRUCTION
          • 147 General
          • PERFORMANCE
          • 148 General
          • 149 Short-Circuit Test for Devices Provided with a Current Transformer
          • 150 Short-Circuit Test for Devices Not Provided with a Current Transformer
          • 151 Calibration Test
          • 152 Breakdown of Components Test
          • RATING
          • 153 Details
          • MARKING
          • 154 Details
        • PART XIII – DEFINITE PURPOSE CONTROLLERS
          • CONSTRUCTION
          • 155 General
          • PERFORMANCE
          • 156 General
          • 157 Overvoltage and Undervoltage Test
          • 158 Overload Test
          • 159 Endurance Test
          • 160 Locked Rotor Endurance Test
          • 161 Part Winding Endurance Test
          • 162 Short Circuit Test
          • RATING
          • 163 Details
          • MARKING
          • 164 Details
        • PART XIV – SERVICE EQUIPMENT
          • 165 General
        • PART XV – LAMP DIMMERS
          • CONSTRUCTION
          • 166 General
          • PERFORMANCE
          • 167 General
          • 168 Temperature Test
          • 169 Operation Test
          • 170 Abnormal Operation Test
          • 170A D-C Offset TestSection 170A Added March 15, 2013
          • RATING
          • 171 Details
          • MARKING
          • 172 Details
        • PART XVI – MISCELLANEOUS DEVICES
          • Construction
          • 173 General
          • PERFORMANCE
          • 173A General
          • 173B Input Test
          • 174 Temperature Test
          • 174A Normal Operation Test
          • 174B Abnormal Operation Test
          • 174C Burnout Test
          • 174D Inoperative Blower Motor Test
          • RATING
          • 175 Details
          • MARKING
          • 176 Details
        • PART XVII – PROGRAMMABLE CONTROLLERS
          • GENERAL
          • 177 Details
          • 178 Glossary
          • CONSTRUCTION
          • 179 General
          • 180 Spacings
          • 181 Separation of Circuit Barriers
          • 182 Bonding
          • PERFORMANCE
          • 183 General
          • 184 Temperature Test
          • 185 Overvoltage and Undervoltage Test
          • 186 Overload Test
          • 187 Endurance Test
          • 188 Dielectric Voltage-Withstand Test
          • 189 Breakdown of Components Test
          • 190 Impedance Test
          • RATING
          • 191 Details
          • MARKING
          • 192 Details
          • 193 Signal Circuits
        • PART XVIII – EQUIPMENT RATED 601– 1500 VOLTS
          • GENERAL
          • 194 Details
          • CONSTRUCTION
          • 195 General
          • 196 Insulating Material
          • 197 Spacings
          • PERFORMANCE
          • 198 General
          • 199 Short Circuit Test
          • 200 Dielectric Voltage-Withstand Test
        • PART XIX – PROXIMITY SWITCHES
          • GENERAL
          • 201 Details
          • 202 Glossary
          • CONSTRUCTION
          • 203 General
          • PERFORMANCE
          • 204 General
          • 205 Infrared Radiation
          • 206 Power-Supply Cord Tests
            • 206.1 General
            • 206.2 Tensile strength and elongation tests
            • 206.3 Oven conditioning
            • 206.4 Oil conditioning
            • 206.5 Ultraviolet light (UV) conditioning
            • 206.6 Cold bend test
          • 207 Cable Gland Connector Tests
            • 207.1 General
            • 207.2 Oven conditioning (rubber composition)
            • 207.3 Oven conditioning (thermoplastic composition)
            • 207.4 Flexing test
            • 207.5 Strain relief test
          • 208 Strain Relief Test
          • 209 Tests for Environmental Type Enclosures
          • RATING
          • 210 Details
          • MARKING
          • 211 Details
    • INDUSTRIAL CONTROL EQUIPMENT FOR MARINE USE
    • APPENDIX A
    • INDEX