The invention relates to a polymer composition comprising a polyethylene and a crosslinking agent, characterized in that the polymer composition contains a total amount of vinyl groups which is B vinyl groups per 1000 carbon atoms, and B1≤B, wherein B1 is 0.88, when measured prior to crosslinking according to method ASTM D6248-98; and in that the crosslinking agent is present in an amount which is Z wt %, based on the total amount (100 wt %) of the polymer composition, and Z≤Z2, wherein Z2 is 0.30, an article being e.g. a cable, e.g. a power cable, and processes for producing a polymer composition and an article; useful in different end applications, such as wire and cable (W&C) applications.