Polycast designs and manufactures a wide range of epoxy switch and bus insulators. We offer hundreds of styles of indoor and outdoor insulators in various voltage classes and for a variety of electrical applications.

Insulators are manufactured and tested for a rated voltage range from 0.6kV up to 46kV. While we manufacture a large selection of standard insulator designs, our engineering team welcomes the opportunity to develop new insulating devices for special applications. New designs are carefully type tested to meet North American and International standards.

Our insulators can be engineered to meet special operating temperatures and application requirements. Standard indoor insulators are designed for ambient temperatures between -5°C to +55°C. Standard outdoor insulators can withstand ambient temperatures ranging from -55°C to +55°C and are recommended for applications where UV, heavy pollution, or condensation are considered factors.

Click the links below for more information about our insulator designs, features, standards, and ratings. Or, contact Polycast today to discuss your electrical insulator requirements.

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Standards and Ratings Summary PDF-icon
Provides summary data for all
Polycast insulators


PII20A Series PDF-icon
Indoor – Switch & Bus
5kV/60kV through 46kV/250kV BIL


PII30A Series PDF-icon
Indoor – Switch & Bus
8.3kV/75kV through 46kV/250kV BIL


POI20A Series PDF-icon
Outdoor – Switch & Bus
5kV/60kV through 46kV/250kV BIL


POI30A Series PDF-icon
Outdoor – Switch & Bus
8.3kV/75kV BIL through 46kV/250kV BIL


PIICS Series PDF-icon
15kV/95kV BIL through 28kV/150kV BIL


PIID Series PDF-icon
0.6kV/10kV BIL through 2.4kV/45kV BIL


PIIW Series PDF-icon
Indoor – Wedge or Block
Contact us for details


PIIT Series PDF-icon
0.6kV/10kV BIL through 15kV/95kV BIL


PIICR Series – Indoor PDF-icon
European Style
5kV/60kV BIL through 25kV/150kV BIL


PIIF Series – Indoor PDF-icon
5kV/60kV BIL through 8.7kV/75kV BIL


PIIX Series – Outdoor PDF-icon
High Cantilever
5kV/60kV BIL


PIIG Series
Indoor – High Cantilever
Contact us for details


PIISL Series
Indoor – Insulating Sleeves
Contact us for details