An unshielded buried service wire (20) includes a core (22) and a jacket (40). The core comprises two pairs (24-24) of insulated metallic conductors (26-26). Also associated with each conductor pair is a longitudinally extending waterblocking member (33) which inhibits the flow of water longitudinally of the wire. The jacket has a transverse cross sectional configuration which is generally oval. Adjacent to each of opposed small radius of curvature portions of the service wire and embedded substantially in the jacket is a longitudinally extending, rod-like strength member (50) which is caused to adhere to plastic material of the jacket.