Summary
Insulation testing helps detect deterioration, humidity, contamination or defects before energizing or during maintenance. The result must be interpreted with criteria, not only as an isolated number.
What the test measures
It measures the resistance shown by insulation under a continuous test voltage during a defined period.
It is applied to cables, circuits, motors, panels, transformers and other assets according to voltage level and scope.
Factors that influence it
Temperature, humidity, dirt, cable length, capacitance, connections and test time can change the result.
That is why it is important to record conditions and compare against suitable criteria.
Interpretation
A high value is usually favorable, but interpretation must consider trend, equipment type, test voltage and historical background.
In some assets, indexes such as PI or DAR are used if the scope and equipment type justify it.
When to request it
Before energizing, after maintenance, after faults, during work acceptance or as part of a predictive plan.
The report supports decisions on repair, replacement or operational continuity.
Frequently asked questions
Can an insulation test damage equipment?
It must be applied with voltage and procedure appropriate to the asset; that is why technical criteria are required.
Can it be compared with old measurements?
Yes, trends are usually more useful than an isolated reading.
What happens if the value is low?
Humidity, damage, dirt, connections or degradation should be investigated before energizing.
Is it useful for cables and transformers?
Yes, although each asset requires appropriate criteria and test voltages.
If you need technical support applied to this topic, review our electrical testing and measurements service.