A heating panel has a metal substrate, ceramic inner and outer insulating layers on the substrate. A film of resistive material forms a heating layer on one of the insulating layers. The heating layer has electrodes on opposite edges connected to different phases of a multiphase power source. Another electrode is connected to a neutral of the power source. Capacitive currents caused in the substrate by the different phases cancel each other. Thus, leakage current is minimized through a conductor connected between the substrate and ground. The heating panel can be adapted for two phase or three phase systems. The heating panels are particularly useful for defining a heating cavity of an oven.