AES: Advanced PV Diagnostics: Insulation Resistance Testing on PV

Insulation resistance testing, or IRT, is akin to pressure testing a water line: applying a voltage to a conductor and seeing if there is any path for current to a different conductor, or to ground. Specified as a commissioning test for PV systems by the International Electrotechnical Commission (IEC), IRT may also be required as preventive maintenance in cases – contractually, by equipment manufacturers, or both.

Additionally, insulation resistance testing is a valuable tool for locating ground-faults. IRT concepts, theory, execution, and evaluation of results are covered in this lesson.