FAA AMT (Aviation Maintenance Technician) Airframe Practice Exam

When electric cables pass through holes in bulkheads, ribs, firewalls, and other structures, they are at risk of being damaged by chafing, which could lead to short circuits or other electrical failures. To prevent this damage, the cables should be protected with a suitable grommet.

A grommet acts as a protective cushion around the cables, reducing the risk of abrasion and chafing against the sharp edges of the holes. Securing the cables tightly with cable ties (Option A) may not provide enough flexibility and protection, potentially causing the cables to chafe against the edges. Applying lubricant (Option B) may not be suitable for preventing chafing as it does not provide physical protection for the cables. Wrapping the cables with heat-shrink tubing (Option D) may provide some level of protection, but a grommet is specifically designed to protect cables passing through holes in structures and is the most appropriate choice for this scenario.