Insulator
Mechanical support that keeps electricity in its intended path.
A simplified disc-style insulator string, shown without the conductor and tower attachments.
An insulator resists electric current and separates energized conductors from structures or other conductors. Overhead line insulators also carry mechanical loads.
Supporting a live conductor without conducting
An overhead line needs mechanical support while its live wires remain electrically separated from the tower or pole. Insulators provide that separation. Their material, size, and shape are chosen for electrical and mechanical conditions.
The familiar discs and ribs increase the surface path between an energized connection and its support. Insulation design must account for wet or contaminated surfaces as well as the voltage across the device.
Why it matters
Insulators allow energized conductors to be carried by structures without creating an intended conducting path into those structures.