Abstract: A heating apparatus for heating an electrically conductive flowable medium includes a pipe having a conductivity no greater than that of the medium and a pair of electrodes projecting in a cantilever fashion into the pipe at spaced locations therealong and each having a noble metal plated surface exposed to the flowable medium. Each electrode is sealed to the wall of the pipe with a flat-faced aspetic seal formed between a flat end face of the elctrode and a cooperating flat face on the pipe wall. The electrodes may be hollow, fluid cooled and have a rounded free end made of an electrically non-conducting material on which is mounted a temperature or pressure sensor. The exposed electrode surface may be partially coated with an electrically insulative material to confine heating current flow to a particular surface portion of the electrode.