What type of protection is required for Type NM cables passing through cut or drilled slots in metal members?

Type NM (nonmetallic sheathed) cables must have adequate protection when passing through cut or drilled slots in metal members to prevent damage to the cable from sharp edges. According to the National Electrical Code, the use of listed grommets or listed bushings is specified to provide this necessary protection.

Listed grommets or bushings serve to mitigate potential abrasion or cutting of the cable's insulation, which is essential for maintaining the integrity and safety of the electrical installation. The grommets or bushings create a smooth transition at the entry points in metal members, effectively safeguarding the cable as it passes through areas where there might be sharp edges.

This requirement underscores the importance of ensuring that all electrical installations comply with safety standards to minimize the risk of electrical failures or hazards. The presence of these protective components is critical for maintaining the longevity and safety of Type NM cables in applications where they encounter metal structures.