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  • Fact Sheet

Electrical Insulation Systems (EIS) Product Standards

UL 1446, the Standard for Safety of Systems of Insulating Materials — General, serves as the model for numerous international standards. Find more information about them here.

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An electrical insulation system (EIS) is comprised of a unique combination of materials that have been verified for chemical compatibility when used at certain maximum temperatures. These combinations are arranged to form insulation systems such as those used in motors, transformers and solenoids.

Systems at 600 volts or less are recognized by UL Solutions for use above Class 105(A) limits. These systems have been tested in accordance with UL 1446. UL 1446 also serves as the model for the following international standards:


IEC 62114

Electrical Insulation Systems — Thermal Classification

IEC 60505

Evaluation and Qualification of Electrical Insulation

IEC 61857

Electrical Insulation Systems — Procedures Part 1: General Requirements-Low Voltage

IEC I61857-21

Electrical Insulation Systems — Procedures Part 21: Specific Requirements for General Purpose Model-Wire Wound Applications

IEC 61858

Electrical Insulation Systems — Thermal Evaluation of Modification to an Established Wire-Wound EIS

We group Recognized systems into two product categories identified by the alphanumeric category control numbers (CCNs) below:

  • Systems, Electrical Insulation (OBJY2) – Applies to insulation systems that are evaluated after being built around supplier components. The UL Recognized EIS is available for coil manufacturers’ use.
  • System Components, Electrical Insulation (OBJS2) – Applies to UL Recognized insulation systems used in facilities where coil is produced. These systems are evaluated for coil manufacturers or adopted from an OBJS2 supplier. Components available for adoption by coil manufacturers can be quickly identified in our online EIS database, UL iQ™ for Electrical Insulation Systems.

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