Diagnostics of HV power cables are playing an important role in the meaning of two aspects: 1) on-site diagnostic of new installation, where a commissioning test has to prove the absence of any defects in the cable insulation and accessories, after transportation and installation. 2) On-site diagnostic of a serviced aged power cable where the condition after a period in service or information about workmanship of repairs has to be known. As it is known some installation defects can result in breakdown even after a successful after-laying test. Obtaining more diagnostic parameters like; Withstand Voltage, Partial Discharges (PD) and Dielectric Loss (tan ¿), providing a indication of insulation condition and accessory performance. In this paper several examples of on-site tests on new and serviced aged XLPE HV power cables will be discussed. Examples of: after-repair, after-laying, and condition assessment tests will be presented as performed with Damped AC diagnostics.@en