For the RIV characteristics test of power apparatus, an indoor measuring system of radio influence voltage was set up and by means of this measuring unit SIV characteristics on the 7$^{1}$2/" pin-type domestic insulators were examined. According to the test data, RIV values of all the test pieces exceeded the maximum permissible level at 10kV applied voltage. The electrical resistivity of domestic semi-conductive glaze as good as importedone but un-uniformity of coating is turned out to be a main cause of failure.lure.