Analysis of cables with visible halos

Halos found in polyethylene cables removed for failure analyses are characterized. The halos are produced by some volatile materials. Water analysis shows a higher water content within the halo than in areas where the halo does not exist. Some organic volatiles introduced at the time of manufacture remain. Acetophenone is variable depending on the particular failure sample. Other organics, some dicumylperoxide decomposition products and some not, are also identified. None of these could be specifically correlated with the presence or absence of the halo. The character of the halos was found to change slowly with time after the cable was removed from the ground. The questions raised by these findings are discussed.