Problems with accessories and/or installation can influence the quality of a newly installed power cable circuit. While manufacturer standards recommends on ‘Go/No-Go’ decision based on simple overvoltage tests, even in a no-breakdown situation presence of defects cannot be excluded, meaning standards do not provide sufficient recommendations for after-laying testing. Damped AC voltage provides sensitive measurement of PD and dielectric losses over a complete cable circuit. This presentation discusses improving test procedures for after-laying testing and diagnostics of all types of on- and offshore power cables. Practical examples using damped AC voltages when testing new connections as well as in assessing condition of service aged cables will also be provided.