1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 508A Industrial Control Panels STANDARD FOR SAFETYUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED MATERIAL NOT AUTHOR
2、IZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Industrial Control Panels, UL 508A Third Edition, Dated April 24, 2018 Summary of Topics This revision of ANSI/UL 508A is being issued to reect the rst time ANSI approval of the Standard. Text that ha
3、s been changed in any manner or impacted by ULs electronic publishing system is marked with a vertical line in the margin. The new and revised requirements are substantially in accordance with Proposal(s) on this subject dated May 18, 2018. All rights reserved. No part of this publication may be rep
4、roduced, stored in a retrieval system, or transmitted in any form by any means, electronic, mechanical photocopying, recording, or otherwise without prior permission of UL. UL provides this Standard as is without warranty of any kind, either expressed or implied, including but not limited to, the im
5、plied warranties of merchantability or tness for any purpose. In no event will UL be liable for any special, incidental, consequential, indirect or similar damages, including loss of prots, lost savings, loss of data, or any other damages arising out of the use of or the inability to use this Standa
6、rd, even if UL or an authorized UL representative has been advised of the possibility of such damage. In no event shall ULs liability for any damage ever exceed the price paid for this Standard, regardless of the form of the claim. Users of the electronic versions of ULs Standards for Safety agree t
7、o defend, indemnify, and hold UL harmless from and against any loss, expense, liability, damage, claim, or judgment (including reasonable attorneys fees) resulting from any error or deviation introduced while purchaser is storing an electronic Standard on the purchasers computer system. JULY 3, 2018
8、 UL 508A tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL JULY 3, 2018 UL 508A tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL APRIL 24, 2018 (Title Page Re
9、printed: July 3, 2018) 1 UL 508A Standard for Industrial Control Panels First Edition April, 2001 Second Edition December, 2013 Third Edition April 24, 2018 This ANSI/UL Standard for Safety consists of the Third Edition including revisions through July 3, 2018. The most recent designation of ANSI/UL
10、 508A as an American National Standard (ANSI) occurred on July 3, 2018. ANSI approval for a standard does not include the Cover Page, Transmittal Pages, and Title Page. Any other portions of this ANSI/UL standard that were not processed in accordance with ANSI/UL requirements are noted at the beginn
11、ing of the impacted sections. Comments or proposals for revisions on any part of the Standard may be submitted to UL at any time. Proposals should be submitted via a Proposal Request in ULs On-Line Collaborative Standards Development System (CSDS) at https:/. ULs Standards for Safety are copyrighted
12、 by UL. Neither a printed nor electronic copy of a Standard should be altered in any way. All of ULs Standards and all copyrights, ownerships, and rights regarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2018 UNDERWRITERS LABORATORIES INC. ANSI/UL 508A-2018UL CO
13、PYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL APRIL 24, 2018 INDUSTRIAL CONTROL PANELS - UL 508A 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS PART 1 GE
14、NERAL USE INDUSTRIAL CONTROL PANELS INTRODUCTION 1 Scope 11 2 Glossary 13 3 Undated References .18 4 Components 18 5 Units of Measurement 18 6 Terminology .19 CONSTRUCTION ALL PANELS 7 General .22 8 Protection Against Corrosion 22 9 Support and Securement of Live Parts .22 10 Spacings 23 11 Conduit
15、Bushings .25 12 Insulating Barriers 26 13 Insulating Materials .27 14 Grounding General 28 15 Grounding Size of Terminal or Bonding Conductor 29 16 Transformer and Power Supply Secondary Grounding 30 17 Identication of Grounding and Grounded Circuit Conductors and Terminals .31 ENCLOSED PANELS 18 En
16、closures .32 19 Enclosure Openings .33 20 Accessibility of Live Parts 35 21 Ventilation Openings 36 21.1 General .36 21.2 Location of ventilation opening .37 21.3 Construction .37 22 Barriers Used with Ventilation Openings .38 23 Observation Windows .39 24 Bonding .39 25 Wire Bending Space 40 26 Enc
17、losure Environmental Control Devices .41 26.1 General 41 26.2 Enclosure fans .41 26.3 Enclosure air conditioner 41 26.4 Enclosure heater .42 26.5 Air lters 42 26.6 Enclosure thermal insulation .42 27 Enclosure Maintenance Lighting 43 27.1 General .43 APRIL 24, 2018 INDUSTRIAL CONTROL PANELS - UL 508
18、A 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 27.2 Component requirements 43 27.3 Circuit requirements 43 POWER CIRCUITS 28 Field Wiring 44 28.1 General .44 28.2 Component requirements 44 28.3 Sizing .45 28.4 Separation of circuits .48
19、28.5 Cord-connected equipment 48 28.6 Receptacles .50 28.7 Cable assemblies and ttings 51 29 Internal Wiring 51 29.1 General .51 29.2 Conductor requirements .52 29.3 Wiring methods 53 29.4 Routing of internal wiring 55 29.5 Separation of circuits .56 29.6 Sizing .56 30 Disconnect Switches 57 30.1 Co
20、mponent requirements 57 30.2 Sizing of disconnect switch 58 30.3 Location .59 30.4 Mechanical operating mechanism 60 31 Branch Circuit Protection 60 31.1 Component requirements 60 31.2 Location .61 31.3 Sizing of branch circuit protection for single motor circuit 62 31.4 Sizing of branch circuit pro
21、tection for motor groups .64 31.5 Receptacles .66 31.6 Sizing of branch circuit protection for heater loads 66 31.7 Sizing of branch circuit protection for appliance loads .67 31.8 Sizing of branch circuit protection for lighting loads .67 32 Overcurrent Protection of Feeder .68 32.1 Component requi
22、rements 68 32.2 Location .68 32.3 Sizing of overcurrent protection 68 32.4 Feeder taps for non-motor loads .68 32.5 Feeder taps for motor loads .69 33 Load Controllers 70 33.1 Component requirements 70 33.2 Sizing/rating of load controllers .70 33.3 Location .71 33.4 Reversing motor controllers 72 3
23、3.5 Wye-delta motor controllers .72 33.6 Controllers for multi-speed and part winding motors 75 33.7 Autotransformer- and resistor-type reduced voltage motor controllers .75 34 Overload Protection of Motor Loads .75 34.1 Component requirements 75 34.2 Sizing of overload relay .75 34.3 Location .76 3
24、5 Power Transformers 77 APRIL 24, 2018 INDUSTRIAL CONTROL PANELS - UL 508A 4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 35.1 Component requirements 77 35.2 Sizing of overcurrent protection for power transformer 77 35.3 Location .79 36 Ot
25、her Circuit Components .79 36.1 Capacitors .79 36.2 Resistors 80 36.3 Reactors 81 36.4 Surge protective devices (SPDs) .81 CONTROL CIRCUITS 37 Field Wiring Terminals .81 37.1 Component requirements 81 37.2 Sizing .82 37.3 Field wiring terminals of a low-voltage limited energy circuit .82 37.4 Field
26、wiring terminals of Class 2 circuits .83 37.5 Separation of circuits .83 37.6 Receptacles .83 37.7 Flexible cords 83 37.8 Cable assemblies and ttings 83 38 Internal Wiring 84 38.1 Component requirements 84 38.2 Sizing of internal control circuit conductors 84 38.3 Wiring methods, wire routing, and s
27、eparation of circuits for internal wiring of a control circuit .85 39 Disconnecting Means .85 40 Overcurrent Protection 85 40.1 Component requirements 85 40.2 Location of overcurrent protective devices .85 40.3 Sizing of overcurrent protection 86 41 Sizing of Overcurrent Protection Control Circuits
28、(Common) 87 42 Overcurrent Protection Control Circuits (Isolated Secondary) .88 42.1 Control transformers 88 42.2 Power supplies .89 42.3 Other isolated secondary sources 90 43 Low-Voltage Limited Energy Circuits 91 43.1 Component requirements 91 43.2 Secondary side requirements 92 44 Class 2 Circui
29、ts .92 44.1 Component requirements .92 44.2 Secondary side requirements 93 45 Switching Devices 93 45.1 Component requirements 93 45.2 Sizing/ratings of control circuit switching devices .94 45.3 Location .96 45.4 Undervoltage protection .97 46 Loads .97 46.1 Component requirements 97 46.2 Location
30、.98 46.3 Rating of control circuit load .98 47 Miscellaneous Devices 99 47.1 Surge protective devices SPDs 99 47.2 Resistors 99 APRIL 24, 2018 INDUSTRIAL CONTROL PANELS - UL 508A 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 47.3 UPS (Uni
31、nterruptible Power-Supply) Equipment 99 48 Pneumatic Switching Devices .100 RATING 49 Supply Ratings 100 50 Individual Load Ratings .101 51 Ratings for Control Circuit Outputs .104 MARKINGS 52 General Markings 104 53 Enclosure Markings 107 54 Field Wiring Terminal Markings 108 55 Cautionary Markings
32、 .112 56 Fuseholder Markings .113 57 Switch Markings .113 58 Overload Relay Heater Table Markings .113 59 Receptacle Markings .113 60 Field Provided Components .114 61 Schematic Wiring Diagrams .114 PART 2 SPECIFIC USE INDUSTRIAL CONTROL PANEL TYPES ENCLOSURES 62 General 114 63 Construction 115 63.1
33、 Metal thickness .115 63.2 Covers and doors .120 63.3 Corrosion protection .124 63.4 Enclosure openings .124 63.5 Ventilation openings .124 63.6 Observation windows 124 64 Markings .124 INDUSTRIAL MACHINERY 65 General 124 66 Construction 125 66.1 Enclosures .125 66.2 Electrical assembly 126 66.3 Gro
34、unding 126 66.4 Field wiring power circuits 127 66.5 Internal wiring power circuits 128 66.6 Disconnecting means 129 66.7 Branch circuit protection .131 66.8 Motor controllers 132 66.9 Internal wiring of control circuit 133 66.10 Overcurrent protection of common control circuit .134 66.11 Operator c
35、ontrols 134 67 Markings .135 APRIL 24, 2018 INDUSTRIAL CONTROL PANELS - UL 508A 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 67.1 Nameplate markings .135 67.2 Operator controls .135 67.3 Components .135 67.4 Cautionary marking 135 CRANE
36、CONTROL 68 General 136 69 Glossary 136 70 Construction 136 70.1 Field wiring terminals of power circuits .136 70.2 Internal wiring .137 70.3 Disconnecting means 138 70.4 Branch circuit protection .139 70.5 Motor overload protection 139 70.6 Field wiring of control circuits .139 70.7 Overcurrent prot
37、ection of control circuit 139 71 Ratings .139 72 Markings .140 SERVICE EQUIPMENT USE 73 General 140 74 Glossary .140 75 Construction 141 75.1 Grounding and bonding 141 75.2 Spacings .148 75.3 Field wiring terminals 148 75.4 Disconnecting means 148 75.5 Neutral disconnecting means .148 75.6 Ground-fa
38、ult protection 149 75.7 Overcurrent protection .153 75.8 Components on the supply side of the disconnecting means .153 76 Ratings .154 77 Markings .154 77.1 Bonded neutral .154 77.2 Insulated neutral 155 77.3 Marking location 155 77.4 Disconnects 155 77.5 Ground-fault protection 155 78 Installation
39、Instructions .156 79 Tests By The Manufacturer Ground-Fault Protection Test .157 ELEVATOR CONTROL 80 General 157 FLAME CONTROL 81 General 158 82 Construction 158 82.1 Component requirements 158 82.2 Spacings .158 APRIL 24, 2018 INDUSTRIAL CONTROL PANELS - UL 508A 7UL COPYRIGHTED MATERIAL NOT AUTHORI
40、ZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 82.3 Internal wiring .159 82.4 Location .159 82.5 Separation of circuits 159 82.6 Overcurrent protection .159 83 Marking 159 MARINE USE 84 General 160 85 Construction 160 85.1 Enclosures .160 85.2 Autotransformer starters .161 8
41、5.3 Insulating materials 161 85.4 Branch circuit overcurrent devices .161 86 Ratings .161 87 Markings .161 AIR CONDITIONING AND REFRIGERATION EQUIPMENT 88 General 161 89 Glossary 162 90 Construction 162 90.1 Field wiring sizing power circuit .162 90.2 Disconnecting switches power circuits .162 90.3
42、Branch circuit protection sizing power circuits .162 90.4 Load controllers power circuits 163 91 Ratings .163 92 Marking 163 FOUNTAIN CONTROL PANELS 93 General 164 94 Construction 164 94.1 Grounding 164 94.2 Ground fault protection .164 94.3 Equipotential bonding 165 94.4 Cord strain relief 165 95 R
43、atings .165 96 Marking 165 INDUSTRIAL CONTROL PANELS FOR IRRIGATION EQUIPMENT 97 General 166 98 Construction 166 98.1 Sizing of motor controller .166 98.2 Disconnecting means 166 98.3 Branch circuit protection .166 98.4 Internal conductors 167 99 Marking 167 CONTROL PANELS FOR AQUATIC PLAYGROUNDS 10
44、0 General .167 APRIL 24, 2018 INDUSTRIAL CONTROL PANELS - UL 508A 8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 101 Glossary .168 102 Construction .168 102.1 Grounding .168 102.2 Ground-fault protection .168 102.3 Transformers and power s
45、upplies 169 103 Ratings 169 104 Marking .169 CONTROL PANELS FOR SWIMMING POOLS AND IN-GROUND SPAS 105 General .169 106 Glossary .170 107 Construction .170 107.1 General .170 107.2 Grounding .170 107.3 Ground-fault protection .171 107.4 Luminaire transformers and power supplies .171 107.5 Cord strain
46、 relief .171 108 Ratings 171 109 Markings 172 CONTROL PANELS FOR WATER PARK RIDES AND SIMILAR INSTALLATIONS 110 General .172 111 Glossary .172 112 Construction .173 112.1 General .173 112.2 Grounding of wave pools .173 112.3 Sensors .173 112.4 Ground fault protection 174 112.5 Luminaire transformers
47、 and power supplies .174 113 Ratings 174 114 Marking .175 SUPPLEMENT SA - Deleted SUPPLEMENT SB - SHORT CIRCUIT CURRENT RATINGS FOR INDUSTRIAL CONTROL PANELS SB1 Scope SB1 SB2 Glossary SB1 SB3 Construction SB1 SB3.1 Internal wiring connections .SB1 SB3.2 Overcurrent protection of control circuit SB1
48、 SB4 Ratings .SB2 SB4.1 Short circuit current rating SB2 SB4.2 Short circuit current ratings of individual power circuit components SB2 SB4.3 Feeder components that limit the short circuit current available .SB6 SB4.4 Determination of the overall short circuit current rating of the panel SB11 JULY 3
49、, 2018 INDUSTRIAL CONTROL PANELS - UL 508A 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL SB5 Markings SB12 SB5.1 General .SB12 SB5.2 Cautionary markings SB12 APPENDIX A Standards for ComponentsA1 APPENDIX B (informative) USE OF COMPONENTS NOT UL LISTED OR RECOGNIZED IN INDUSTRIAL CONTROL PANELS B.1 Scope B1 B.2 Conditions of Use B2 B.2.1 Enclosures .B2 B.2.2 Power supplies B4 B.2.3 Inputs B5 B.2.4 Outputs B5 B.3 Responsibility of the
