UL 873 : 2012

FOREWORD
INTRODUCTION
1. Scope
2. Glossary
3. Units of Measurement
4. Components
5. References
CONSTRUCTION
6. General
7. Frame and Enclosure
8. Mounting
9. Parts Containing Liquid Metal
10. Adjustment Stop
11. Operating Mechanism
12. Reset Mechanism - Limiting Control
13. Means for Calibration
14. Protection Against Corrosion
15. Insulating Material
16. Supply Connections
17. Current-Carrying Parts
18. Switches
19. Internal Wiring
20. Low-Voltage External Wiring Requirements
21. Grounding
22. Bonding of Internal Parts
23. Protection of Users and Service Personnel
24. Protection Against Injury to Persons
25. Capacitors
26. Fuseholders
27. Receptacles
28. Protection of Control-Circuits
29. Short-Circuit, Ground-Fault, Overload and Thermal
     Protection
30. Mercury-Tube Switches
31. Coil Windings
32. Spacings
33. Alternate Spacings - Clearances and Creepage
     Distances
34. Wiring Space
35. Separation of Circuits
36. Class 2 Power Sources and Circuits
37. Barriers
PERFORMANCE
38. General
39. Power Input
40. Temperature Test
41. Leakage Current Test
42. Leakage Current Following Humidity Conditioning
     Test
43. Operation Test
44. Calibration-Verification Test
45. Overload Test
46. Endurance Test
47. Dielectric Voltage-Withstand Test
48. Volt-Ampere Capacity Test
49. Burnout Test
50. Short Circuit Test
51. Parts Containing Liquid Metal Test
52. Two-Step Operation Surface-Unit Controls Test
53. Strain-Relief Test
54. Accelerated Aging Tests on Gaskets, Sealing
     Compounds, and Adhesives
55. Metallic Coating Thickness Test
56. Rain Test
57. Time-Calibration Verification Test
58. Snap-On Covers Test
59. Bonding Conductor Tests
60. Permanence of Marking Test
61. Strength of Adjustment Stop Test
62. Polymeric Materials Tests
63. Class 2 Power Sources and Circuit Tests
64. Isolated-Limited Secondary and Non-Class 2 Circuits
     Tests
MANUFACTURING AND PRODUCTION TESTS
65. Details
66. Grounding Continuity
RATING
67. General
68. Class 2 Power Sources and Circuits
MARKING
69. General
70. Wiring
71. Calibration Setting
72. Elevated Air Temperature
73. Location
74. Cautionary Markings
75. Class 2 Power Sources and Circuits
76. Instructions
SPECIAL-PURPOSE DEVICES
77. Scope
78. Fan/Heat Sequencers
79. Fluorescent Lamp Ballast Protectors
80. Control-Circuit Temperature-Limiting Devices for
     Temperature Protection of Enclosures of Motors and
     Generators for Use in Hazardous Locations
81. Single-Operation Devices
82. Thermal Protective Devices for Lighting Fixtures
83. Controllers for Solar-Energy Systems
84. Temperature-Regulating Thermostats for Household
     Drip-Type Coffee Makers
APPENDIX A
Standards for Components

Specifies electrical equipment for control of air-conditioning, heating, cooking, refrigeration, and humidity, rated 600 volts or less, to be used in ordinary locations in accordance with the National Electrical Code, NFPA 70.