This guide describes tests performed and provides processes to be followed during the commissioning of electrical and control systems in hydroelectric plants. Guidance for methods to be used, organization, and execution of the testing are provided. While the guide does not provide prescriptive procedures that are plant and equipment specific, tests are described along with reference standards for more information. The commissioning of electrical equipment may be for a new hydroelectric plant installation; rehabilitation of an existing hydroelectric plant; or replacement and upgrade of existing electrical equipment.