UL 917
Standard for Clock-Operated Switches

DETAILS
Edition Number:5SCC Approved:--
Edition Date:2006-11-10DOD Approved: --
Price Code:AANSI Approved: --
Type:ulstd

  • SCOPE

    1 Scope

    1.1 These requirements cover clock-operated switches rated 600 V or less, to be used in ordinary locations designed to close and open circuits to a load at predetermined intervals, and intended to be employed in accordance with the National Electrical Code, ANSI/NFPA 70.

    1.2 These requirements cover only clock-operated switches in which the switching contacts are actuated by a clock-work, by a gear-train, by hand, by electrically-wound spring motors, by electric clock-type motors, or by equivalent arrangements. In addition to closing and opening the switching contacts, the devices may also indicate the time of day or time interval.

    1.3 These requirements do not cover devices incorporating electronic timing circuits or switching circuits without separable contacts.

    1.4 A clock-operated switch, which is incomplete in construction features or restricted in performance capabilities, is acceptable for use as a factory-installed component provided that the restrictions established for the component are eliminated when the component is installed.

    1.5 Specific provisions are included in these requirements for TV rated clock-operated switches.

    1.6 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, electric shock, or injury to persons shall be evaluated using the appropriate additional component and end-product requirements as determined necessary to maintain the acceptable 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 cannot be judged to comply with this Standard. Where considered appropriate, revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this Standard.

  • TABLE OF CONTENTS
    Expand All

    • Cover
    • Transmittal
    • Table of Contents
      • Body
        • INTRODUCTION
          • 1 Scope
          • 2 Glossary
          • 3 Components
          • 4 Units of Measurement
          • 5 References
        • CONSTRUCTION
          • 6 Frame and Enclosure
            • 6.1 General
            • 6.2 Nonmetallic
            • 6.3 Cast metal
            • 6.4 Sheet metal
            • 6.5 Covers
            • 6.6 Openings
            • 6.7 Screens and expanded metal
            • 6.8 Conduit openings
          • 7 Rainproof Enclosures
          • 8 Mounting
            • 8.1 General
            • 8.2 Plug-in devices
          • 9 Assembly
          • 10 Operating Mechanism
          • 11 Corrosion Protection
          • 12 Insulating Material
          • 13 Field Connections
          • 14 Supply Connections
            • 14.1 Permanently connected devices
            • 14.2 Connections for wiring systems
            • 14.3 Terminals
          • 15 Cord-Connected Devices
            • 15.1 Cords and plugs
            • 15.2 Polarization
            • 15.3 Strain relief
            • 15.4 Bushings
          • 16 Grounding
          • 17 Receptacles
          • 18 Bonding of Internal Parts
            • 18.1 General
            • 18.2 Construction and connection
          • 19 Current-Carrying Parts
          • 20 Internal Wiring
          • 21 Coil Windings
          • 22 Spacings
          • 23 Field-Wiring Space
        • PERFORMANCE
          • 24 General
          • 25 Leakage Current Test
          • 26 Temperature Test
          • 27 Overload Test
          • 28 Endurance Test
          • 29 Tungsten-Filament-Lamp Load Test
          • 29A Electronic Ballast, CFLs and LED Driver Rated Controls
          • 30 Test Conditions
          • 31 Rain Test
          • 32 Dielectric Voltage-Withstand Test
          • 33 Impact Test
          • 34 Metallic Coating Thickness Test
          • 35 Gasket Tests
          • 36 Grounding Resistance Test
          • 37 Strain Relief Test
          • 38 Snap-On Cover Tests
          • 39 Knockout Secureness Test
          • 40 Humidity Test
          • 41 Abnormal Operation Test
            • 41.1 Adverse conditions of operation
            • 41.2 Abnormal Switching Test
        • RATINGS
          • 42 Details
        • MARKINGS
          • 43 Details
        • TV RATED SWITCHES
          • GENERAL
          • 44 Details
          • CONSTRUCTION
          • 45 Enclosure
            • 45.1 General
            • 45.2 Insulating material
            • 45.3 Switch enclosure openings
            • 45.4 Wire leads
          • PERFORMANCE
          • 46 General
          • 47 Test Circuit
          • 48 Test Conditions
          • 49 Overload Test
          • 50 Endurance Test
          • 51 Temperature Test
          • 52 Dielectric Voltage-Withstand Test
          • 53 Continued Endurance Test
          • 54 Dielectric Voltage-Withstand Test (Repeated)
          • RATINGS
          • 55 Details
          • MARKINGS
          • 56 Details