A load insulator having an elongated, load bearing, electrically insulating body extending between and coupled to opposite metal lugs, for coupling the load insulator in a loaded line, has an electrically insulating cover formed on the outside of the body and extending over and completely covering each of the pair of metal lugs at the opposite ends of the body. The insulating cover, which is of integral, one-piece construction, and may be made of polyurethane, is formed within a mold during construction of the load insulator by leaving a void within the mold around the opposite metal lugs and the body before introducing plastic into the mold, to form the insulating cover. Covering each of the opposite metal lugs as well as the body with the insulating cover forces high voltage-produced currents through the inside of the load insulator by preventing current creep around and flashing over the outside of the insulator body. The integral, one-piece construction of the insulating cover prevents rain water and other moisture from seeping into the inside of the load insulator. The outer surface the body is provided with plural ribs or sheds, at least some of which are substantially larger than and protrude further out than intervening ribs of smaller size to prevent rain water and dirt from forming a continuous current path over the outer surface of the body.