Interpreting the Requirements of Articles 500-516 of the NEC

196 Pages·2017·14.77 MB·English

Interpreting the Requirements
of Articles 500-516 of the NEC®
2017 National Electrical Code® Review
A Guide for the Use of Appleton™ Products in Hazardous Locations

TABLE OF CONTENTS
Introduction 1
General Information 3
NEC® ARTICLES 100, 500 THROUGH 516 – TEXT AND COMMENTARY
Article 100 – Definitions 11
Article 500 – Hazardous (Classified) Locations, Class I, II, and III, Divisions 1 and 2
Changes to Article 500 19
500.1 Scope — Articles 500 Through 504 19
500.3 Other Articles 19
500.4 General 19
500.5 Classifications of Locations 19
500.6 Material Groups 22
500.7 Protection Techniques 24
500.8 Equipment 26
500.9 Specific Occupancies 30
Article 501 – Class I Locations
Changes to Article 501 31
501.1 Scope 31
501.5 Zone Equipment 31
501.10 Wiring Methods 31
501.15 Sealing and Drainage 35
501.17 Process Sealing 43
501.20 Conductor Insulation, Class I, Divisions 1 and 2 44
501.25 Uninsulated Exposed Parts, Class I, Divisions 1 and 2 44
501.30 Grounding and Bonding, Class I, Divisions 1 and 2 44
501.35 Surge Protection 45
501.100 Transformers and Capacitors 45
501.105 Meters, Instruments, and Relays 45
501.115 Switches, Circuit Breakers, Motor Controllers, and Fuses 47
501.120 Control Transformers and Resistors 47
501.125 Motors and Generators 48
501.130 Luminaires 50
501.135 Utilization Equipment 53
501.140 Flexible Cords, Class I, Divisions 1 and 2 54
501.145 Receptacles and Attachment Plugs, Class I, Divisions 1 and 2 55
501.150 Signaling, Alarm, Remote-Control, and Communications Systems 56
Article 502 – Class II Locations
Changes to Article 502 57
502.1 Scope 57
502.5 Explosionproof Equipment 57
502.6 Zone Equipment 57
502.10 Wiring Methods 57
502.15 Sealing, Class II, Divisions 1 and 2 60
502.25 Uninsulated Exposed Parts, Class II, Divisions 1 and 2 60
502.30 Grounding and Bonding, Class II, Divisions 1 and 2 61
502.35 Surge Protection — Class II, Divisions 1 and 2 61
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502.100 Transformers and Capacitors 61
502.115 Switches, Circuit Breakers, Motor Controllers, and Fuses 62
502.120 Control Transformers and Resistors 62
502.125 Motors and Generators 63
502.128 Ventilating Piping 64
502.130 Luminaires 64
502.135 Utilization Equipment 65
502.140 Flexible Cords — Class II, Divisions 1 and 2 66
502.145 Receptacles and Attachment Plugs 67
502.150 Signaling, Alarm, Remote-Control, and Communications Systems; and Meters, Instruments, and Relays 67
Article 503 – Class III Locations
Changes to Article 503 69
503.1 Scope 69
503.5 General 69
503.6 Zone Equipment 70
503.10 Wiring Methods 70
503.25 Uninsulated Exposed Parts, Class III, Divisions 1 and 2 71
503.30 Grounding and Bonding — Class III, Divisions 1 and 2 71
503.100 Transformers and Capacitors — Class III, Divisions 1 and 2 72
503.115 Switches, Circuit Breakers, Motor Controllers, and Fuses — Class III, Divisions 1 and 2 72
503.120 Control Transformers and Resistors — Class III, Divisions 1 and 2 72
503.125 Motors and Generators — Class III, Divisions 1 and 2 72
503.128 Ventilating Piping — Class III, Divisions 1 and 2 72
503.130 Luminaires — Class III, Divisions 1 and 2 72
503.135 Utilization Equipment — Class III, Divisions 1 and 2 73
503.140 Flexible Cords — Class III, Divisions 1 and 2 73
503.145 Receptacles and Attachment Plugs — Class III, Divisions 1 and 2 73
503.150 Signaling, Alarm, Remote-Control, and Local Loudspeaker Intercommunications Systems — Class III, Divisions 1 and 2 74
503.155 Electric Cranes, Hoists, and Similar Equipment — Class III, Divisions 1 and 2 74
503.160 Storage Battery Charging Equipment — Class III, Divisions 1 and 2 74
Article 504 – Intrinsically Safe Systems
Changes to Article 504 75
504.1 Scope 75
504.2 Definitions 75
504.3 Application of Other Articles 75
504.4 Equipment 75
504.10 Equipment Installation 75
504.20 Wiring Methods 76
504.30 Separation of Intrinsically Safe Conductors 76
504.50 Grounding 77
504.60 Bonding 78
504.70 Sealing 78
504.80 Identification 78
Article 505 – Zone 0, 1, and 2 Locations
Changes to Article 505 79
505.1 Scope 79
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505.2 Definitions 79
505.3 Other Articles 80
505.4 General 80
505.5 Classifications of Locations 81
505.6 Material Groups 82
505.7 Special Precaution 83
505.8 Protection Techniques 83
505.9 Equipment 84
505.15 Wiring Methods 88
505.16 Sealing and Drainage 90
505.17 Flexible Cords and Connections 94
505.18 Conductors and Conductor Insulation 95
505.19 Uninsulated Exposed Parts 95
505.20 Equipment Requirements 95
505.22 Increased Safety “e” Motors and Generators 95
505.25 Grounding and Bonding 96
505.26 Process Sealing 96
Article 506 – Zone 20, 21, and 22 Locations for Combustible Dusts or Ignitable Fibers/Flyings
Changes to Article 506 99
506.1 Scope 99
506.2 Definitions 99
506.3 Other Articles 100
506.4 General 100
506.5 Classification of Locations 100
506.6 Material Groups 101
506.7 Special Precaution 101
506.8 Protection Techniques 102
506.9 Equipment Requirements 103
506.15 Wiring Methods 104
506.16 Sealing 106
506.17 Flexible Cords 106
506.20 Equipment Installation 106
506.25 Grounding and Bonding 107
Article 510 – Hazardous (Classified) Locations – Specific
Changes to Article 510 109
510.1 Scope 109
510.2 General 109
Article 511 – Commercial Garages, Repair and Storage
Changes to Article 511 111
511.1 Scope 111
511.2 Definitions 111
511.3 Area Classification, General 111
511.4 Wiring and Equipment in Class I Locations 112
511.7 Wiring and Equipment Installed Above Class I Locations 113
511.8 Underground Wiring 114
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511.9 Sealing 114
511.10 Special Equipment 114
511.12 Ground-Fault Circuit-Interrupter Protection for Personnel 115
511.16 Grounding and Bonding Requirements 115
Article 513 – Aircraft Hangers
Changes to Article 513 117
513.1 Scope 117
513.2 Definitions 117
513.3 Classification of Locations 117
513.4 Wiring and Equipment in Class I Locations 117
513.7 Wiring and Equipment Not Installed in Class I Locations 117
513.8 Underground Wiring 118
513.9 Sealing 118
513.10 Special Equipment 118
513.12 Ground-Fault Circuit-Interrupter Protection for Personnel 119
513.16 Grounding and Bonding Requirements 119
Article 514 – Motor Fuel Dispensing Facilities
Changes to Article 514 121
514.1 Scope 121
514.2 Definition 121
514.3 Classification of Locations 121
514.4 Wiring and Equipment Installed in Class I Locations 126
514.7 Wiring and Equipment Above Class I Locations 126
514.8 Underground Wiring 126
514.9 Sealing 127
514.11 Circuit Disconnects 127
514.13 Provisions for Maintenance and Service of Dispensing Equipment 127
514.16 Grounding and Bonding 127
Article 515 – Bulk Storage Plants
Changes to Article 515 129
515.1 Scope 129
515.3 Class I Locations 129
515.4 Wiring and Equipment Located in Class I Locations 129
515.7 Wiring and Equipment Above Class I Locations 129
515.8 Underground Wiring 132
515.9 Sealing 132
515.10 Special Equipment — Gasoline Dispensers 132
515.16 Grounding and Bonding 132
Article 516 – Spray Application, Dipping, Coating, and Printing Processes Using Flammable or Combustible Materials
Changes to Article 516 135
516.1 Scope 135
516.2 Definitions 135
516.4 Area Classification for Open Containers 136
516.5 Area Classification for Spray Application Processes 137
516.6 Wiring and Equipment in Class I Locations 140
516.7 Wiring and Equipment Not Within Classified Locations 141
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516.10 Special Equipment 141
516.16 Grounding 143
516.18 Area Classification for Temporary Membrane Enclosures 143
516.23 Electrical and Other Sources of Ignition 144
516.29 Classification of Locations 144
516.35 Areas Adjacent to Enclosed Dipping and Coating Processes 146
516.36 Equipment and Containers in Ventilated Areas 146
516.37 Luminaires 146
516.38 Wiring and Equipment Not Within Classified Locations 146
516.40 Static Electric Discharges 147
APPENDIXES
Appendix A-1: Class I Flammable Gases And Vapors 149
Appendix A-2: Class II Combustible Dusts 155
Appendix B-1: Applicable Product Standards 159
Appendix B-2: NEMA Enclosure Definitions 161
Appendix B-3: Comparison Between NEMA Enclosure Type Numbers and IEC® Enclosure Classification Designations 162
Appendix C: Standards, Testing and Certification 164
Appendix D: Quick Selection Guide — Equipment for Hazardous Locations 166
Appendix E-1: Lighting and Power Diagrams: Class I, Divisions 1 and 2, Group B; Class I, Zones 1 and 2, Groups IIA, IIB + H 170
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Appendix E-2: Power Diagram: Class I, Division 1, Groups C and D, Class I, Zone 1, Groups IIA, IIB 172
Appendix E-3: Lighting Diagram: Class I, Division 1, Groups C and D; Class 1, Zone 1, Groups IIA and IIB 174
Appendix E-4: Lighting and Power Diagram: Class I, Division 2, Groups C and D; Class I, Zone 2, Groups IIA and IIB 176
Appendix E-5: Power Diagram: Class II, Divisions 1 and 2, Groups E, F and G; Class II, Zones 21 and 22 178
Appendix E-6: Lighting Diagram: Class II, Divisions 1 and 2, Groups E, F and G; Class II, Zones 21 and 22 180
Appendix E-7: Lighting and Power Diagram: Class I, Zone 1; Class I, Zone 2 182
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INTRODUCTION
PURPOSE OF THE REVIEW Material taken from the National Electrical Code is reprinted
with permission from NFPA 70®-2017, National Electrical Code®,
• Assist in interpreting the requirements of Articles 500-516 Copyright © 2016, National Fire Protection Association, Quincy,
of the 2017 NEC®. MA. This material is not the official position of the NFPA on the
referenced subject, which is represented only by the standard in
its entirety which standard can be obtained through the NFPA
• To provide information that will assist in minimizing the fire
website www.nfpa.org. The National Fire Protection Association
and explosive hazards encountered in classified locations,
did not produce, review or approve this Handbook and assumes
including references to sources where more detailed
no responsibility for the application or use of any NEC® related
information can be obtained.
material or product set out herein. National Electrical Code® and
NEC® are registered trademarks of the National Fire Protection
• To provide the reader with an overview of the various types
Association, Quincy, MA.
of electrical equipment, and equipment design, used in
hazardous locations.
Appendix A contains tables of flash points and auto ignition
temperatures for common hazardous gases and vapors as well
• To provide a guide for the correct selection and installation
as information on ignition temperatures for hazardous dusts.
of electrical products in hazardous (classified) locations, in
conformance with the National Electrical Code®.
Appendix B contains an informative list of associated
CODE EXCERPTS/NOTATIONS installation standards for electrical equipment with which
Appleton™ products are designed, tested, and manufactured to
• The 2017 National Electrical Code® Articles 500 thru 516 comply. This appendix also includes the NEMA Enclosure Type
are indicated with black text. definitions and a practical conversion chart that can be used to
convert a NEMA Enclosure Type to an IEC® IP Classification.
• Underlined text indicates a change from the previous
NEC® edition. Appendix C contains an informative list of electrical and fire
safety organizations.
• Emerson staff commentaries, where practical, where
practical, has been located directly following the published
Appendix D contains an informative quick selection guide of
NEC® rule.
Appleton™ products for each type of hazardous location.
• Commentaries on NEC® presented in blue text.
Appendix E contains clarifying diagrams of typical Appleton™
hazardous location product installations.
Reprinted with permission from NFPA 70®-2017, National Electrical Code®, Copyright © 2016, National Fire Protection Association, Quincy, MA.
This material is not the official position of the NFPA on the referenced subject, which is represented only by the standard in its entirety. 1
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NOTES
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