What is an Insulation Tester?

An insulation tester, also known as a megger, is a specialized instrument used to measure the insulation resistance of electrical equipment or wiring. It’s commonly employed in the maintenance and troubleshooting of electrical systems to ensure their safety and reliability.

The principle behind insulation testing is to apply a high-voltage direct current (DC) to the insulation being tested and measure the resistance. This high voltage is used to stress the insulation and reveal any weaknesses or faults. The higher the insulation resistance, the better the condition of the insulation. Conversely, a low insulation resistance indicates potential issues such as moisture ingress, degradation of insulation materials, or other faults that could lead to electrical failures or safety hazards.

Insulation testers come in various forms, ranging from handheld devices suitable for fieldwork to more sophisticated instruments for laboratory use. They typically provide readings in ohms or megohms and may have additional features such as data logging, adjustable test voltages, and safety features to protect both the operator and the equipment under test.

Insulation testing is a crucial part of routine maintenance programs for electrical systems, helping to identify potential problems before they lead to equipment failures, downtime, or safety hazards.