Analysis of surface current characteristics flowing on cord plug surface in accelerated tracking tests

Tracking of a cord plug of household appliance connected to an outlet is considered one of causes of fire accident, which is observed when dust is accumulated in the space between the plug and the outlet and then wetted by dew condensation. It is strongly requested to detect the tracking in order to interrupt power supply before ignition. In the present study, a novel method was developed to detect current flowing on a cord plug surface between electrodes, whose magnitude is much smaller than that of a load current. Results of fundamental studies on surface current characteristics under artificially contaminated and wetted conditions and their relation with tracking progression are reported.