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High Voltage Insulator

An electrical insulator is a material that impedes the free flow of electrons. Insulators of different classes and materials are used as mechanical supports for transmission and distribution lines, as well as substation lines. Due to their resistivity, these insulators also are installed to prevent line damage from arcing. 

Products include:

  • Insulators or insulating parts of wet-process porcelain or toughened glass, or non-ceramic composites, whether or not assembled with metal parts, used in the transmission or distribution of electrical energy or for use as a part of a large electrical machine or piece of equipment; and  
  • Clamps, fittings, and accessory hardware used directly with such insulators or insulating parts that affect their functioning.​

NEMA offers the opportunity to develop product Standards and advocate for technical and industry positions that are in the best interests of Member companies, the industry, and the users of their products throughout North America and the world. Members accomplishes this mission through active, effective, and organized marketing and technical programs, and related activities.​



  • Develops and maintains industry proprietary Standards on guy strain, suspension, and post insulators
  • Maintains secretariat to American National Standards Institute (ANSI) to draft ASC 29 Standards   on insulators for electric power lines
  • Participates in direct harmonization efforts between U.S. and global standards to ensure that foreign markets remain open to Members' products
  • Administers the U.S. Technical Advisory Group (TAG) to the International Electrotechnical Commission (IEC) that promotes harmonization with European and global standards ​


  • Meets directly with elected officials, federal regulators, and other aligned trade groups to address tariffs and other trade issues ​


  • Transmission and distribution systems, including substations and large electrical machinery


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