UL 1446
Standard for Systems of Insulating Materials - General

Edition Number:7SCC Approved:--
Edition Date:2016-11-11DOD Approved: --
Price Code:BANSI Approved: 2019-02-04


    1 Scope

    1.1 These requirements cover test procedures to be used in the evaluation of Class 120(E) or higher electrical insulation systems (EIS) where the thermal factor is the dominating aging factor. These requirements also cover the investigation of the substitution of non-electrical insulating materials (NIM) components of insulation in a previously evaluated insulation system and also the test procedures to be used in the evaluation of magnet wire coatings, magnet wires, and varnishes.

    1.2 These requirements for the evaluation of an EIS do not establish thermal ratings for/or alter established thermal ratings for individual components.

    1.3 These requirements do not cover insulation systems exposed to radiation or operating in oils, refrigerants, soaps, or other media that potentially degrade insulating materials.

    1.4 When any performance aspect of an end-product requirement is not covered by this standard, the applicable standard shall be used.

    1.5 These requirements do not cover electrical insulation systems where transient overvoltages or partial discharge are present. Such electrical insulation systems shall be evaluated to the appropriate standard for the application. Such standards include, but are not limited to the following:

    a)    The Test Procedure for Thermal Evaluation of Insulation Systems for Dry-Type Power and Distribution Transformers, Including Open-Wound, Solid-Cast, and Resin-Encapsulated Transformers, IEEE C57.12.60;

    b)    The Standard for Rotating Electrical Machines – Part 18-31: Functional Evaluation of Insulation Systems – Test Procedures for Form-Wound Windings – Thermal Evaluation and Classification of Insulation Systems Used in Rotating Machines, IEC 60034-18-31; or

    c)    The Recommended Practice for Thermal Evaluation of Unsealed or Sealed Insulation Systems for AC Electric Machinery Employing Form-Wound Pre-Insulated Stator Coils for Machines Rated 15 000 V and Below, IEEE 1776.

    Expand All

    • Cover
    • Transmittal
    • Table of Contents
      • Body
          • 1 Scope
          • 2 Units of Measurement
          • 3 References
          • 4 Glossary
          • 5 Insulation Systems
            • 5.1 General
            • 5.2 EIS components
          • 6 Electrical Insulation Systems – Full Thermal Aging
            • 6.1 General
            • 6.2 Samples
            • 6.3 Exposures
            • 6.4 Diagnostic tests – determination of end of test-life
            • 6.5 Analysis and evaluation
        • MARKING
          • 7 Details
    • Varnishes and Impregnating Resins