This study was conducted under both industrial and laboratory conditions for improving material properties (i.e. mechanical and electrical) of electroporcelain bodies produced by porcelain insulator factories in Turkey. To achieve this aim, the quartz content of a standard electroporcelain body was substituted by alpha-alumina. The technical and sintering behaviours of quartz and the alumina-substituted bodies were investigated. Results showed that the addition of alumina increased the mechanical and electrical strength of the materials.