Insulation compositions for electric power cables having a polyolefin base polymer and an additive comprising either low molecular weight wax or polyethylene glycol (PEG) and optionally further comprising one or more hindered amine light stabilizers, amine antioxidants and other antioxidant blends are disclosed. Also disclosed are insulation compositions comprising a C2 to C8 alpha olefin in combination with a polyethylene homopolymer together with, optionally, one or more hindered amine light stabilizer and a liquid cresol antioxidant.