What happens when electrical insulation fails?

Electrical insulation is more than just a plastic polymer material that wraps wires, it is a complete cable insulation system, casing insulator, conduit space, motor and general purpose equipment. Mechanical stress, contamination, and temperature changes can cause these components to deteriorate over time, leading to current leakage.


Current leakage problem: Current flow through the insulation creates heat, which deteriorates the insulation until it fails and can pose a fire hazard. The leakage current must be returned to the source and will flow back to the source through any available conductors, ducts, pipes, water, or ground. This unfavorable current creates dangerous voltages. Leakage current is inefficient. The current leaking through the insulation does not drive the motor, light, or heat, but it still consumes. The leakage current causes the overcurrent protection device to trip, overheating the motor and transformer.


The result is poor electrical insulation, leading to equipment failure and production line downtime. Now, no factory can survive an unplanned shutdown. "Customers need to diagnose faults quickly. No one wants to waste production time, and many customers are eager to know whether they need to repair the equipment or simply replace it. At this time, the insulation resistance tester came in.


The insulation resistance tester applies a DC voltage to the insulation system and measures the current generated. This makes it possible to calculate and display the resistance value of the insulation, the extent to which the insulation binds current in the wire, or the degree to which the current leakage is prevented. The role of insulation resistance tester greatly solves the customer's worries. By testing the insulation resistance of different components in an electrical system (transformers, switchgear, wires, motors), technicians can isolate and repair faulty components.


Use an insulation resistance tester to verify the high insulation resistance between the conductor and the ground or adjacent conductor. Two common examples are testing the insulation between the motor windings and the motor base, and checking the resistance between the phase conductor and the grounding wire/cage. Before the electrical system is officially energized, the use of insulation tests to verify that it is intact can improve the performance of the system; Insulation testing can uncover manufacturing process issues and equipment defects, which can often be discovered before equipment fails.