The cable of the same specification produced in Wuhan outdoor in 1998

2009 and 2013 were selected to compare the tensile properties of the sunny and back faces of the cable

and the tensile properties of the PE sheath under the long-term natural conditions were measured.The results show that the performance of the cable sheath will decrease significantly with the extension of the outdoor placement time.The tensile strength retention rate of the black jacket after 9 years and 20 years of natural environment aging are 92% and 71%

respectively.The elongation at break are 88% and 76%

respectively.The tensile strength of the sheath on the sunny side accounted for 93.7% and 71.8% of the back surface

and the elongation at break accounted for 80% and 96.6%.The oxidation induction period of the sunny surface（OIT） reduced to 32.9 min

14.3 min.The tensile strength retention and elongation at break of the orange jacket after 5 years of natural environmental aging are 41% and 1%

respectively

and the tensile strength of the sunny surface decreased to 64.7% of the strength of the back surface.The rate is only 1.5%

and the OIT of the orange jacket is Omin.