It can detect a difference of as little as four to six mille-amps or mA. What is life saving about these is that often the difference in the current is because the leakage is through the body of a person who is grounded. When that happens, the circuit can be shut off in a thirtieth of a second. If a person accidentally touches the energized part of a circuit and there is not a GFCI in the line, that shock could be lethal. Depending on where you are in the world, there are different names for the same device. In some parts of the world they are referred to as residual current devices (RCD), or residual current circuit breakers (RCCB). In the United States and Canada they are GFCI's or GFI, ground fault interrupter. Sometimes they are referred to as an ALCI or appliance leakage current
It can detect a difference of as little as four to six mille-amps or mA. What is life saving about these is that often the difference in the current is because the leakage is through the body of a person who is grounded. When that happens, the circuit can be shut off in a thirtieth of a second. If a person accidentally touches the energized part of a circuit and there is not a GFCI in the line, that shock could be lethal. Depending on where you are in the world, there are different names for the same device. In some parts of the world they are referred to as residual current devices (RCD), or residual current circuit breakers (RCCB). In the United States and Canada they are GFCI's or GFI, ground fault interrupter. Sometimes they are referred to as an ALCI or appliance leakage current