isloatsiooniseadme kogutakistus seiratava süsteemi klemmide ja maa vahel, mõõdetuna nimisagedusel, total impedance of the insulation monitoring device between the terminals to the system being monitored and earth, measured at the nominal frequency fn, measure of the opposition to current flow (impedance), both static (resistance) and dynamic (reactance), into the load network being connected that is internal to the electrical source