GFCI circuit testing with a LowZ function DMM скачать в хорошем качестве

GFCI circuit testing with a LowZ function DMM

One method to test a Ground Fault Circuit Interruptor (GFCI) load side of the circuit using a Digital Multimeter (Fluke 116) with the LowZ function. Why does this work? The LowZ function has an input of impedance of 3,000 ohms, where Volts AC function has an input impedance of greater than 10,000,000 ohms. Ohms law tells us on a 120vac circuit, using Volts AC will output 0.01 mA. Using LowZ will result in 40 mA. GFCI are designed to trip once the imbalanced of ground and neutral is greater than 5 mA. With Volts AC function, there is less than the designed 5 mA going to ground. With Low-Z function you get greater than 5 mA difference. Therefore, the GFCI devise is doing its job.