Electrical Standoff Insulators

High-Strength FRP Insulators — Shatter, Moisture & Flame-Resistant


Glastic Standoff Insulators are molded of Underwriters Laboratories Incorporated (UL®) Recognized flame-resistant fiberglass-reinforced thermoset polyester molding compound.

Insulators 1603, 2015, 1461,1872, 4610 and 4640 are UL Recognized according to UL Standard for Safety 891. They feature shatter resistance and closer height tolerances than commonly available in porcelain insulators. Moisture and heat resistance properties of these Insulators are higher than those of conventional plastic insulators. For more information about UL: www.ul.com

Voltage Rating

This is only meant to be a guide for indoor service. Fiberglass reinforced polyester (frp) insulators mounted within a suitable electrical cabinet are considered indoors even though the cabinet itself is outdoors. An insulator will withstand its rated voltage continuously but industry standards or other specifications may require a different spacing from conductor to ground for a particular voltage. Wet or dirty conditions may require derating an insulator.

Outdoor Use

Electrical standoff insulators are primarily intended to be used indoors or inside a suitable enclosure. Insulators 4610 and 4640 should not be used upside down if there is a possibility of the center hole filling with water.

Short Time Electrical Strength

For most electrical standoff insulator designs, this is the external flashover voltage in air. A few insulators will puncture instead. The value given is an average of 15 parts tested.

One end of the frp insulator is bolted to a flat plate and force is applied to the insert on the other end in a direction parallel to the end at a distance from the plate equal to the insulator height.

Torque Strength

One end of the insulator is bolted to a flat plate and a normal steel bolt is tightened into the insert on the other end with a torque wrench. The bolt will fail before the insulator and the values published are approximately the values at which bolts fail. If you use tensile steel bolts, the insert threads will strip before the bolts fail, but at higher torque values than we publish. 5KV and 15kV insulators are tested differently.

UL Recognition

All Glastic Insulators are molded from UL Recognized molding materials (UL File E23525). When submitting your equipment to UL, you may need to furnish the molding material grade number used for a particular insulator. This information is available from Mar-Bal, Incorporated. All of the molding materials used in our Insulators have a generic relative Thermal Index of 130° C electrical/130° C mechanical. 1603, 2165, 2015, 1461,1872, 4610 and 4640 Insulators are UL Recognized according to UL standard for Safety 891 (UL File E81713).