PV Insulation Resistance Test

PV Insulation Resistance Test: what is it and why perform it?

The insulation resistance test is an electrical safety test and shows whether a solar module offers adequate insulation.

With an insulation resistance test, manufacturers, installers, and quality testers can assess if a solar panel has adequate insulation between its electricity-conducting components and the module's frame or, in the case of a frameless panel, the outside world. Badly designed PV modules may have insulation problems. Common causes for insufficient insulation are for instance solar cells that are too closely positioned to the frame. Another common cause of insufficient insulation resistance is material weakness, such as modules that were poorly laminated with low-quality encapsulates.

PV insulation resistance test PV insulation resistance test

During the test, a dielectric strength tester is used to apply DC voltage of up to 1000 V, plus twice the maximum system voltage, to the module. To pass this test, the PV module should not show any surface tracks, nor any functional breakdown or development of leakage paths. Current leakage may occur on the edges of the solar panel or through the back sheet. For standard solar panels (modules with an area larger than 0.1 m2), the resistance should not be less than 40MΩ for every square meter.

Nowadays solar panel manufacturers use advanced flash test machines that also test the insulation resistance of the solar panel. As this is an important safety aspect of the pv module, according to IEC 61215 standard the insulation resistance test needs to be installed at every manufacturer's assembly line.

Michael
By

Michael

on 23 Jan 2018

is it a dielectric test (3kV is applied (for 1000V system voltage)) that is required in the production line or a isolation resistance measurement (1kV is applied)? IEC61215/730 are about type approval... These modules can degrade during this approval up to 5% and I wonder if the manufacturers will apply such a high voltage and risk the degradation by that.

bunty
By

bunty

on 22 Jun 2016

how can solution in insulation fault ?

James Dowling
By

James Dowling

on 21 Nov 2020

Interesting article, thanks for posting it. However I have noticed an error in your test set-up description. The resistance should not be less than 40MΩ for every square meter. - Mega Ohms per square meter, not Ohms.

Torsten
By

Torsten

on 20 Dec 2021

Yes, please correct the 40 ***Mega*** Ohms. This article is quoted by Google as the top hit for "pv module insulation resistance" search

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