(57) An improved electrically insulating polymer composition is provided, wherein said polymer composition comprising an olefinic polymer as a principal ingredient and functional group containing monomeric units of monomers D1 through D4 at a rate of 5x10⁻⁷ to 5x10⁻³ mols per gram of the composition, and also comprising ethylenic linkages at a rate of not smaller than 0.8 per 1,000 carbon atoms and/or aromatic ring containing monomeric units of monomer D5 at a rate of 5x10⁻⁷ to 5x10⁻³ mols per gram of the composition, wherein said monomers D1 through D5 have an ethylenic linkage, the monomer D1 is a carbonyl group or carbonyl group derivative containing monomer, the monomer D2 is a hydroxyl group containing monomer, the monomer D3 is a nitro group containing monomer, the monomer D4 is a nitrile group containing monomer, and the monomer D5 is an aromatic ring containing monomer.
And there is also provided a wire or a cable having an electrically insulating polymer composition as defined above or an insulating layer made of such a composition or a material obtained by crosslinking such a composition.