UL 1778
Standard for Uninterruptible Power Supply Equipment

DETAILS
Edition Number:2SCC Approved:--
Edition Date:1994-10-25DOD Approved: --
Price Code:DANSI Approved: --
Type:ulstd

  • SCOPE

    1 Scope

    1.1 These requirements cover uninterruptible power supplies (UPS) rated 600 volts or less ac or dc that are intended for installation in accordance with the National Electrical Code , NFPA 70 . During normal operation, the UPS allows the primary or normal power source to deliver ac power to the protected load through either the power conversion portion of the UPS or a bypass source. The power conversion portion of the UPS consists of a rectifier, an inverter, or both. During periods of power fluctuations, or power outages, or both, the connected load receives ac power from the battery supply and power conversion portion of the UPS.

    1.2 Products that are used with UPS and that are covered by this standard include:

    a)    Remote battery supply cabinets with or without batteries;

    b)    Remote status panels;

    c)    Bypass switches;

    d)    Maintenance bypass switches;

    e)    Rectifier, power conversion units, or both; and

    f)    Power distribution panels.

    1.3 A battery supply (see 2.4 ) used with a UPS covered by this standard may consist of any of the following described in (a) – (c):

    a)    A battery supply that is integral with the UPS. The batteries may or may not be furnished with the UPS.

    b)    A battery supply that is contained in a remote cabinet. For a cord-and-plug-connected UPS having an ac input rating of 20 amperes or less and 125 volts ac maximum, the battery supply is furnished with the UPS. For all other UPS intended for use with a remote battery and cabinet assembly, the battery supply may or may not be furnished with the UPS.

    c)    A battery supply that is contained in a separate battery room. This type of battery supply may or may not be furnished with the UPS.

    1.4 These requirements cover static type UPS– not rotary type UPS.

    1.5 This standard does not cover Uninterruptible Power Supplies (UPS) intended for use in health care facilities. UPS intended for use in such facilities shall comply with the requirements of this standard and the Standard for Safety of Medical Electrical Equipment, Part 1: General Requirements, UL 60601-1. UPS that employ hospital grade components identified by the markings "Hospital Only", "Hospital Grade", or a green dot on the body of the component, or otherwise implying suitability for medical use shall be evaluated to these standards.


    1.5 revised effective May 27, 2005

    1.6 These requirements cover UPS equipment that may be installed in accordance with the Standard for Protection of Electronic Computer/Data-Processing Equipment , ANSI/NFPA 75 . This equipment is marked indicating that it is suitable for such use. See 72.1.27 .

    1.7 Engine-driven, dc power generators intended to provide backup power for the battery supply circuit of UPS units are investigated for compliance with the requirements in the Standard for Engine-Generator Assemblies for Use in Recreational Vehicles, UL 1248.

    1.8 These requirements do not cover UPS units for use as emergency systems nor legally required standby systems described in Articles 700 and 701 respectively of the National Electrical Code , ANSI/NFPA 70 .

    1.9 Deleted May 27, 2004

    1.10 Any undated reference to a code or standard appearing in the requirements of this standard shall be interpreted as referring to the latest edition of that code or standard.


    1.10 added May 27, 2004

  • TABLE OF CONTENTS
    Expand All

    • Cover
    • Transmittal
    • Table of Contents
    • UL Foreword
      • Body
        • PART 1 – ALL UPS EQUIPMENT
          • INTRODUCTION
          • 1 Scope
          • 2 Glossary
          • 3 General
            • 3.1 Components
            • 3.2 Units of measurement
          • CONSTRUCTION
          • 4 Materials
          • 5 Frame and Enclosure
            • 5.1 General
            • 5.2 Modular units
            • 5.3 Access covers
            • 5.4 Cast metal enclosures
            • 5.5 Sheet metal enclosures
            • 5.6 Nonmetallic enclosures
            • 5.7 Glass covered openings
            • 5.8 Openings for wiring
            • 5.9 Openings in an enclosure
            • 5.10 Enclosure bottom openings
            • 5.11 Enclosure top openings
            • 5.12 Guards
          • 6 Sharp Edges
          • 7 Protection of Users – Accessibility of Uninsulated Live Parts, Film-Coated Wire, and Moving Parts – and User Servicing
          • 8 Electric Shock
            • 8.1 Voltage
            • 8.2 Stored energy
          • 9 Mounting
          • 10 Corrosion Protection
          • 11 Mechanical Assembly
          • 12 Switches and Controls
          • 13 Disconnection Device
          • 14 Receptacles
          • 15 Supply Connections
            • 15.1 Fixed units
            • 15.2 Openings for conduit or cable connection
            • 15.3 Openings for class 2 circuit conductors
            • 15.4 Cord-connected units
            • 15.5 Strain relief
            • 15.6 Bushings
            • 15.7 Interconnections between sections
            • 15.8 Identification
          • 16 Wire Bending Space
          • 17 Output Circuit Grounding
          • 18 Equipment Grounding
          • 19 Bonding of Internal Parts
          • 20 Internal Wiring
            • 20.1 Wires
            • 20.2 Protection of wiring
          • 21 Current-Carrying Parts
            • 21.1 General
            • 21.2 Bus bars
            • 21.3 Live heat sinks
          • 22 Electrical Connections
          • 23 Spacings
            • 23.1 General
            • 23.2 Insulation barriers
          • 24 Control Circuits
          • 25 Accessible Signal Circuits
          • 26 Transformers
            • 26.1 General
            • 26.2 Coil insulation
          • 27 Separation of Circuits
            • 27.1 Factory wiring
            • 27.2 Separation barriers
            • 27.3 Field wiring
          • 28 Overcurrent Protection
            • 28.1 General
            • 28.2 Control circuits
            • 28.3 Output alternating current power circuits
            • 28.4 Battery supply circuits
            • 28.5 Inverter storage capacitors
          • 29 Backfeed Protection
          • 30 Motors
          • 31 Capacitors
          • 32 Resistors
          • 33 Lampholders
          • 34 Printed-Wiring Boards
          • 35 Insulating Materials
          • 36 Flammability Classification of Internal Materials
            • 36.1 General
            • 36.2 Air filters
          • 37 Adhesives
          • 38 Battery Supplies
            • 38.1 General
            • 38.2 Enclosure
            • 38.3 Battery mounting
            • 38.4 Enclosure ventilation
            • 38.5 Batteries
            • 38.6 Overcurrent protection
            • 38.7 Isolation
          • 39 Protection of Service Personnel
          • 40 Harmonic Distortion
          • PERFORMANCE
          • 41 General
          • 42 Leakage Current Test
          • 43 Leakage Current Test Following Humidity Conditioning
          • 44 Power Input Test
          • 45 Temperature Test
          • 46 Load Temperature Test
          • 47 Dielectric Voltage-Withstand Test
            • 47.1 General
            • 47.2 Maximum-voltage measurements
            • 47.3 AC and DC power circuits
            • 47.4 Secondary circuits
            • 47.5 Induced potential
          • 48 Backfeed Protection Test
            • 48.1 General
            • 48.2 Electromagnetic interference filters
          • 49 Harmonic Distortion Test
          • 50 Volt-Ampere Capacity Measurement
          • 51 Neutral to Ground Potential Measurement Test
          • 52 Abnormal Tests
            • 52.1 General
            • 52.2 Transformer burnout test
            • 52.3 Transformer overload test
            • 52.4 Output overload test
            • 52.5 Short circuit test
            • 52.6 Overcharge test
            • 52.7 Capacitor surge current test
            • 52.8 Capacitor fault test
            • 52.9 Forced ventilation test
            • 52.10 Component short- and open-circuit test
            • 52.11 Electrolytic capacitor fault test
            • 52.12 Load transfer
            • 52.13 Mismatch voltage test
          • 53 Flanged Bobbin Transformer Abnormal Test
          • 54 Strain Relief and Flexing Tests
            • 54.1 Strain relief
            • 54.2 Flexing
            • 54.3 Push-back relief
          • 55 Grounding Impedance Test
          • 56 Overcurrent Protection Calibration Test
          • 57 Battery Compartment Ventilation Test
          • 58 Strength of Terminal Insulating Base and Support Test
          • 59 Strength of Handles Test
          • 60 Mechanical Strength Tests for Metal Enclosures
          • 61 Evaluation of Reduced Spacings on Printed-Wiring Boards
            • 61.1 General
            • 61.2 Dielectric voltage-withstand test
            • 61.3 Shorted trace test
          • 62 Bonding Conductor Test
          • 63 Stability Test
          • 64 Impact on Glass Covered Openings
          • 65 Impact Test – Guards Over Moving Parts
          • 66 Heat Sink Temperature Cycling Test
          • 67 Tests for Permanence of Cord Tag
            • 67.1 General
            • 67.2 Test conditions
            • 67.3 Test method
          • 68 Ignition Test Through Bottom-Panel Openings
            • 68.1 General
            • 68.2 Hot, flaming oil test
          • 69 Tests on Transformer Insulating Materials
          • 70 Bus Bar Tests
          • 70A Maximum Output VA Measurement Test
          • 70B Emergency DC Power Off Test
          • RATING
          • 71 Details
          • MARKING
          • 72 Details
            • 72.1 General
            • 72.2 Cautionary markings
          • INSTRUCTIONS
          • 73 Instruction Manual
          • 74 Important Safety Instructions
            • 74.1 General
            • 74.2 Batteries
            • 74.3 Vented batteries
          • 75 Installation Instructions for Cable TV Uninterruptible Power Supplies
          • MANUFACTURING AND PRODUCTION TESTS
          • 76 Production-Line Dielectric Voltage-Withstand Test
          • 77 Production-Line Grounding-Continuity Test
        • PART 2 – OUTDOOR-USE UNITS
          • INTRODUCTION
          • 78 General
          • CONSTRUCTION
          • 79 Enclosure and Corrosion Protection
          • PERFORMANCE
          • 80 Rain Test
          • 81 Accelerated Aging Test
          • 82 Metallic Coating Thickness
          • MARKING
          • 83 Details
        • PART 3 – ACCESSORY EQUIPMENT AND CONVERSION UNITS
          • INTRODUCTION
          • 84 Scope
          • CONSTRUCTION
          • 85 Details
          • PERFORMANCE
          • 86 Installation Test
          • MARKING
          • 87 Details
    • APPENDIX A
    • Superseded List