Evaluation of foam-skin cables for aerial applications

Since the introduction of foam-skin filled cables, there has been considerable discussion within the Industry, both pro and con, regarding the acceptability of foam-skin filled cables for aerial application. This paper reports on results obtained from a study undertaken to evaluate the changes in transmission properties of such cables in a simulated aerial environment. Cable samples produced by six cable manufacturers using conventional, high-temperature drip-resistant filling compounds with a petrolatum base were subjected to temperature cycling from -40 F to 140 F. Transmission parameters were measured at 1, 150 and 772 kHz and compared to initial values. A solid polypropylene insulated filled cable was included for reference. The results show that foam-skin petrolatum based filled cables exhibit stable electrical characteristics when exposed to cycled temperature extremes.