Why Do We Blast Glass Insulators with High-Pressure Water?

If you've ever looked up at power lines or transmission towers and noticed strings of strange-looking discs hanging between the tower and the wire, you’ve seen electrical insulators. These components are critical for the safety and efficiency of high-voltage power transmission, but what exactly are they, and why do workers sometimes spray them with high-pressure water?

What is an insulator?

Electrical insulators are essential components in overhead power transmission systems. Their primary function is to prevent electrical current from flowing from the live wire to the grounded support structures, such as power towers or utility poles.

Insulators are installed between the power line and the supporting tower to block the path of electricity to the ground. This is especially important because high-voltage transmission lines often carry tens of thousands of volts using bare conductors with no external insulation.

Why Wash Insulators with High-Pressure Water?

Over time, insulators are exposed to:
Industrial dust
Pollution particles
Bird droppings
Smoke or salt fog in coastal areas
These contaminants can form a conductive layer on the surface of the insulator. When moisture is present, this layer can cause leakage current, corona discharge, or even a flashover.

To prevent this, utility companies conduct regular insulator washing—either with the power turned off or while the line is still live.

Types of Cleaning

Offline Cleaning: Performed with the power turned off for complete safety.
Live-Line Cleaning: Utilizes deionized water, which has very low conductivity, allowing it to be sprayed at high-voltage lines without risk of electrocution.

This cleaning process restores the insulator’s dielectric performance, preventing faults and extending service life.

Conclusion

Electrical insulators may look simple, but they are a vital part of high-voltage transmission systems. From material choice to shape optimization and even regular cleaning routines with high-pressure water, every aspect of their design and maintenance contributes to ensuring the safety and stability of the power grid.
So next time you see workers spraying water high into the air near power lines, remember—they’re not cleaning the wires; they’re protecting your electricity.