Abstract: A plasma burner comprises an electrode holder which carries a tubular outer electrode and a coaxially arranged central electrode, and an electrical current supply source, which can be coupled via current feeders to the outer and central electrodes respectively. Also a device is provided for feeding gas into the region of the electrodes, between which an arc is produced for plasma formation. The tubular outer electrode has a first cooled, arc-inactive tube section, consisting of electrically conductive metal, and an adjoining second arc-active uncooled tube section, which consists of heat-resistant and electrically conductive material, and which is releasably connected to the first tube section. The arc passes between the second tube section and the neighboring arc-active section of the coaxial central electrode.

Abstract: An electrode holder for arc furnace electrodes having a cooled metal shaft at least partially surrounded by a protective jacket of hollow cylinder configuration, generally moldings resistant to elevated temperatures. The protective jacket can surround and protect portions of the electrode holder positioned within the furnace or portions of the electrode holder in a zone engaged by clamping jaws. The protective jacket consists of individual moldings configured to provide generally ring shapes which may be put together to form rings, and coherently surrounding the metal shaft.