Safety testing of electrical devices/work equipment according to VDE 0701-0702, DGUV regulation 3 (BGV A3) and BetrSichV. Mains operation enables the testing of devices with power supply units, such as electronically controlled devices/ tools, PCs, copiers and washing machines under functional conditions. Protective conductor resistance with ≥ 200 mA pulse test current - necessary for oxidised contacts. Insulation resistance with 250 V and 500 V test voltage. Protective conductor / contact current in differential method / direct measurement in mains operation and in substitute leakage current method in battery operation. Active measurement of protective conductor current of 3-phase devices under functional condition with optional measuring adapter. Testing of permanently installed and mobile 30 mA RCD/PRCD circuit breakers with measurement of the tripping time. Voltage measurement at external earthed socket.