E talafeagai mo le faia o le fuaina o le insulation teteʻe (IR), absorption ratio (DAR), polarization index (PI), leakage le taimi nei (Ix) ma absorption capacitance (Cx) o ituaiga uma o meafaigaluega eletise maualuga, e aofia ai switchgear, transformers, reactors, capacitors, motors, generators ma uaea, ma isi.