Type NM cables passing through metal members must be protected by ______ installed prior to cable installation.

Type NM cables, which are commonly used for residential wiring, must be safeguarded when they pass through metal members to prevent damage from sharp edges or surfaces. This protection is critical to ensure the integrity of the cable and to maintain the safety of the electrical system.

When selecting a protective method, listed bushings or listed grommets are two appropriate options. Listed bushings are devices that help protect wires from abrasion when passing through metal that could potentially cut into the insulation. Similarly, listed grommets serve a similar purpose by covering the edges of holes where the wire might be drawn through, thereby reducing the risk of wear.

The requirement for protection measures like bushings or grommets prior to cable installation ensures that the cables are properly shielded during the wiring process and throughout their use. Therefore, the correct answer encompasses both listed bushings and listed grommets, acknowledging that either can provide the necessary protection for Type NM cables in this scenario.