An electrical capacitance test is a test which determines the ability of a body to store an electrical charge, and it is used in a lot of different industries. It is a standard test used to determine the quality of all electrical products, and is a test well suited to determining whether or not a roof leaks.
This test works for roof leaks due to how water can store an electrical charge. This means that somebody who wants to find out if they have a roof leak, they can do a quick electrical capacitance test to check.
The test is a lot cheaper and quicker to do than alternatives like the thermal imaging test. Unfortunately it is no where near as precise, and for certain types of roofs it will give a false positive, like with roofs which contain a layer of foil.