Insulation testers (ohmmeters)

Insulation tester (megaohmmeter)

— instruments that can be used to test the quality of the insulation.

For such a check, it is enough to determine the electrical resistance of the insulation — however, in this case it can be very high, in millions of ohms and even more. Thus, the traditional measurement method — applying a low voltage to the material, determining the strength of the received current and calculating the resistance — is not suitable for insulation, special procedures are needed. Devices that provide such capabilities are called megohm metres. They may support different insulation test methods; these techniques are described in more detail in special sources, and the features of specific devices — in the manufacturer's documentation.

Separately, we note that modern megohmmeters are rarely made in the form of highly specialized devices — most often these are the same universal multimeters, supplemented with an insulation tester mode.