Electrode consumption depends on

• Oxidation of the surface of the electrode
• Mechanical losses due to fracture
• Dissolution in slag during carbon boil

The diameter of the electrode should correspond to the current supplied; if current density is excessively high, electrodes will be heated and oxidized vigorously. The electrode current could vary from 12 to  for 400 to 600 m electrode diameter. Larger electrode diameter increases electric energy consumption.

The electrodes are positioned at apexes of an equilateral triangle. The diameter of the circle passing through the centers of electrodes is called the diameter of the electrode spacing. If the electrodes are placed close to each other and far from furnace walls, the charge at the furnace banks will be heated belatedly. With large spacing diameter, electric arcs will burn near the walls, which will result in rapid wear of the lining.

The electrode spacing diameter for the bath diameter could be 0.45 for small furnaces, 0.35 for medium- sized and large furnaces, and still lower for super- powerful furnaces. For a bath diameter of 5560 mm of a 100 ton furnace the electrode spacing diameter would be .

Side walls  

The side walls refractory materials should be able to withstand thermal shock and corrosive action of slag. Hot spot is formed on the side walls due to the radiation from arc flames, reflected from bath surface during  power input. The side wall is lined with magnesite, dolomite or chrome magnesite bricks up to the slag line. The side wall thickness is usually 450 to 500mm for 10 to 50 ton furnaces and 550 to 650mm for 100 to 200 ton furnaces.