Halogen-free extra-high-voltage cable for railway rolling stock

A halogen-free extra-high-voltage cable for railway rolling stock, comprising:

• a stranded conductor;
• an inner semi-conducting layer covering the stranded conductor;
• an outer semi-conducting layer provided on an outer periphery of the inner semi-conducting layer via an insulation layer;
• and
• a sheath layer on an outer periphery of the outer semi-conducting layer, the sheath layer containing 80 to 200 parts by weight of metal hydroxide and 0.5 to 10 parts by weight of cross-linking agent with respect to 100 parts by weight of olefin-based polymer containing at least 50 parts by weight ethylene-vinyl acetate copolymer, the ethylene-vinyl acetate copolymer having a vinyl acetate content of not less than 40 wt % and less than 50 wt % and a melt flow rate of not more than 2.5 g/10 min and a resin composition is cross-linked,
• wherein the sheath layer comprises mechanical characteristics of tensile strength of not less than 8 MPa and breaking elongation of not less than 200% in a test in accordance with JIS C 3005, aging resistance of tensile strength retention of not less than 70% and breaking elongation retention of not less than 60% after heating at 100° C. for 168 hours, oil resistance of the tensile strength retention of not less than 60% and the breaking elongation retention of not less than 60% after immersing in IRM 902 oil at 100° C. for 24 hours, low temperature characteristics of the breaking elongation of not less than 100% after cooling at −40° C. for 10 minutes, and the breaking elongation of not less than 30% after cooling at −50° C. for 10 minutes, and
• wherein the cable comprises flame retardancy of char length of not more than 2.5 m in a vertical flame test in accordance with BS 6853.