When electrical systems and equipment are installed or modified, all implementations must be tested and documented before use. The tests described in this book cover all possible forms of electrical systems as well as equipment for machines and machine installations. The scope of the tests depends on the extent of the system or equipment and its technical components. For simple electrical systems and equipment, only a few tests and basic documentation are necessary, which are comprehensively described in this book. The book includes practical interpretation aids and extensive information on how individual protective measures work and how they should be tested. The positive reception of the book necessitates a new edition. In addition to a number of corrections, the standardization developments have been taken into account, with specific DKE announcements completing the work. Practical commentary on the initial testing of electrical systems (DIN VDE 0100-600), the initial testing of electrical equipment for machines according to DIN EN 60204-1 (VDE 0113-1), and periodic testing of electrical systems and equipment (DIN VDE 0105-100/A1) is provided. It also presents common measuring devices and measurement setups. Extensive practical checklists are included. The explanations refer to DIN VDE 0100-600 for electrical systems, DIN EN 60204-1 (VDE 0113-1) for electrical equipment for machines and machine installations, and DIN VDE 0105-100/A1 for recurring tests. Reference is also made to commercially available measuring devices that are very helpful during the tests and allow for simple measurement setups. Extensive checklists complete the work.