silmusahela/kontuuri vooluallika, faasijuhi ja voolu tagasitee, nt katsejuhi, maanduselektroodi ja maa, näivtakistuste/impedantsi summa mõõtepunktist kuni vooluallika teise klemmini, sum of the impedance in a current loop comprising the impedance of the source of the current, the impedance of the phase conductor, e.g. prodective conductor, earth electrode and earth, from the point of measurement to the other terminal of the source of the current