As a result of a thorough and persistent search, the author has reached the conclusion that there is in use in this country no scientific basis for determining the thickness of impregnated paper insulation on high voltage cables. In the earlier days, when impregnated paper cables were first made, the manufacturers appear to have adopted the thicknesses of insulation previously used on cables with rubber insulation. No bending tests were made on these earlier cables, and the cables were installed with the same sharp bends that had previously been found permissible with rubber-insulated lead-covered cables. Our later knowledge indicates that many of these early failures must have been due to the tearing of the paper insulation caused by the bending during installation. Many of the older foremen and splicers who were raised on rubber insulated cables were quite firmly of the idea that it did not matter how sharp a bend or kink was made in the cable during its installation so long as these sharp bends and kinks were removed before leaving the cable in its final position.