Insulated wire comprising a flame-retardant polyolefinic resin composition

An insulated wire comprising:

• a conductor;
• and
• a coating formed on said conductor, wherein said coating is a cross-linked flame-retardant resin composition comprising:
• (a) a thermoplastic polyolefinic resin having a density of smaller than 0.89 g/cm3, prepared by copolymerizing ethylene and a non-polar α-olefin in the presence of a single-site metallocene catalyst;
• (b) a halogen-containing flame retardant;
• and
• (c) zinc oxide, wherein the cross-linked flame-retardant resin composition has an initial tensile strength of not less than 1.05 kg/mm2 and an initial elongation of not less than 100%, as stipulated in the UL Standards;
• and wherein the resin composition has a flame resistance that satisfies all the following three requirements in the VW-1 perpendicular combustion test:
• 1) the longest burn time for the sample is within 60 seconds;
• 2) the kraft paper attached to the upper side of the sample is not burnt;
• and
• 3) the absorbent cotton disposed below the sample is not burnt by the burnt droppings of the sample;
• and wherein the resin composition has a modulus of tensile elasticity of not larger than 10 kg/cm2 and has a specific dielectric constant less than 3.3.