The task of the final thesis was to review the most commonly used methods for testing electrical installations with an emphasis on the measurement procedure. Measurements are mainly carried out on installed equipment and in real conditions. Using the equipment and knowing the procedure requires certain skills of the measurer as well as compliance with all safety regulations. The second chapter of the final thesis describes the procedure for testing the continuity and resistance of conductors for potential equalization. Data on the minimum conductor cross-section and maximum length before exceeding the limit values are presented. The second part describes the procedure for using metal elements for potential equalization, and the procedure for measuring resistance is presented. The third chapter discusses the procedure for testing insulation resistance. The procedure for testing insulation resistance for group and individual testing is presented. The procedure for measuring insulation resistance for a three-phase system is also presented, and data on the test voltage and the minimum permitted resistances obtained are presented. The fourth chapter gives the differences between TT, TNS and TNCS systems and shows the path of the earth fault current in the event of a fault on a consumer. The method for measuring the impedance of the fault loop is presented together with the connection of the measuring device. Chapter 5 presents the procedures for testing circuit breakers. The basic classifications, operating principles, advantages and disadvantages of circuit breakers are presented. The testing procedure for ELCB is not presented because it is being replaced by newer solutions, but the procedure for testing RCD switches using a device for testing the speed of switch response is presented.