High voltage testing can be broadly classified into testing of insulating materials (samples of dielectrics) and tests on completed equipment. The tests carried out on completed equipment are the measurement of capacitance, the power factor or the total dielectric loss, the ultimate breakdown voltage and the flash-over voltage.
This test covers the determination of the linear shrinkage of a disturbed soil sample. It is a tedious and expensive test that is done only on soils (other than sands) when the dispersion percentage is >50 or volume expansion tests fail to saturate or shrink. This test is performed on dispersive soils only.
Megger test is also known as insulation resistance test. This method is used for determining the condition of electrical insulation has been widely used for many years as a general nondestructive test method. The test consists in measuring the Insulation resistance of a device under test, while phase and neutral are short circuited together.