Abstract: A covering or sleeve can include an insulating material, such as a polymeric material, that is permanently printed with indicia identifying the particular circuit to which a wire belongs. In an embodiment, the sleeve is printed to permanently mark the sleeve with indicia identifying the room or space the covered electrical wire is sourcing. The sleeves can optionally be color-coded as a secondary identification system according to known color-coding in the industry. The printed sleeves can be sold individually and then subsequently applied to the electrical wires at the electrical source, such as an electrical box. In another embodiment, wiring can be covered with the printed sleeves and packaged individually, or in a set, such as on an electrical panel. In other embodiments, methods of identifying electrical wiring are disclosed.