Very Low Frequency (VLF) dielectric testing is an essential method for evaluating the integrity of underground low voltage (LV), medium voltage (MV), and high voltage (HV) cables. This test involves applying a very low frequency alternating current to the cable to assess its insulation and detect any potential faults. It helps identify weak points in the insulation that could lead to failures. VLF testing is particularly effective for cables with oil-impregnated paper or cross-linked polyethylene insulation. By conducting regular VLF dielectric tests, operators can ensure increased reliability of the electrical network, extend the lifespan of cables, and reduce unexpected maintenance costs.