Pulp Insulation for Telephone Cables

A new type of insulation has been developed by the Bell System engineers and put into use for exchange area cables. This insulation consists of a continuous pulp or paper sleeve formed directly on the conductor by a modified paper making process. The manufacture and use of pulp-insulated wire cables involves unique changes in manufacturing equipment, materials and methods, in cable design and installation practises. The development has covered a period of some ten years and is the result of combined manufacturing, engineering, and field studies.