A number of electrical devices contain insulating oil. These oils are produced from highly refined mineral oils and have insulating properties. They do not have free electrons that can carry an electric current and are polarized with an electric field. Therefore, the electrical conductivity is very weak or almost nonexistent. Their resistivity is very high and therefore they can hardly pass electrical currents. It also has high oxidation stability.

In this way, puncture voltage tests are absolutely applied in the maintenance programs of all electrical devices with insulating oils. In order to achieve the high efficiency expected from these tests, it is very important to perform a puncture stress test at least twice a year, but at least once a year and to record the results carefully, in order to be prepared for unexpected and sudden situations.

Puncture voltage tests are provided by laboratories accredited by national or international accreditation organizations within the scope of electrical tests.

In laboratories, these tests begin by applying routine test voltage. For this purpose, two electrodes are placed in a container in a certain range and oil is filled. Alternating current is applied to the ends of the electrodes. The amount of voltage is increased in certain steps until it encounters a short circuit. As soon as a short circuit occurs, the current is immediately cut off. The current value of this voltage short circuit is the result of the test. These values ​​can be of different norms. The manufacturer of the insulating oil shows this value in the catalog. These norms include the shape, size of the electrodes, the amount of voltage to be applied, the number of applications, whether the oil needs to be mixed during the test and the required distance between the electrolytes.

While performing the breakdown voltage tests, the laboratories take into consideration the conditions and criteria in the current legal regulations and the relevant standards developed by domestic and foreign organizations.