If your existing power cable comes up short, but the device should stay where it is, the Lindy C13 to C14 extension cable is the optimal solution for the office and home. The existing cable must have a C13 socket and the device a C14 plug.
Cable: H05-VVF 3G 1.0 mm²
Connectors: IEC male - IEC female
(IEC 60320 C13 female straight - IEC 60320 C14 male straight)