What is an Insulator?

By Justin Felles

When you look at power lines, you’ll notice the wire never directly touches the wooden pole or tower and instead connects to an insulator. That’s because electricity is always trying to find the easiest path to the ground, and metal and wood are conductive, or able to carry electricity. Insulators are objects made from materials that are highly resistant to electric flow, such as glass, porcelain, plastic and silicone, and keep the wire from touching the pole to prevent electricity flow.

Porcelain and glass insulators have been used since the earliest days of electric transmission, but they attract condensation, which is conductive, and are difficult to make. Most insulators are now made of silicone materials that are lighter, cheaper and water repellent.

Insulators have ridges or discs that reduce the flow of electricity – with about four ridges or discs for low-voltage lines, and up to 25 discs for high-voltage transmission lines.