Pin-Type vs Suspension Glass Insulators: Choosing the Right Insulator

Pin-type and suspension glass insulators solve different problems. Pick the wrong one and you pay in outages or unnecessary cost.

Pin-type glass insulators

Best for distribution lines up to about 33 kV and short tap spans. They mount on a steel pin, are quick to install, and need no crossarm hardware string. Example: the 20 kV P-20T.

Suspension glass insulators

Best for high-voltage and long-span lines (66 kV and up). Discs hang from the crossarm in strings, so each unit is interchangeable and voltage scales by adding discs.

Quick decision rule

• Distribution / tap / low voltage → pin-type
• Sub-transmission / transmission, long spans → suspension strings
• Substation bus supports → solid-core post insulators (ZSW series)