What is the primary purpose of insulation in aircraft wiring?

• A. Insulation prevents short circuits and protects against environmental factors.
• B. Insulation is used solely to reduce conductor weight.
• C. Insulation increases charging susceptibility.
• D. Insulation is optional in most wiring harnesses.

Answer: (B)

Insulation in aircraft wiring is there to keep electrical paths separate and to protect the conductor from the surrounding environment. Its main job is to prevent short circuits by maintaining electrical isolation between conductors and between a conductor and the aircraft structure, while also guarding against moisture, heat, vibration, chemicals, and abrasion that could degrade the wire over time. The idea that insulation exists mainly to reduce weight isn’t accurate—insulation adds weight and is chosen for how well it resists heat, moisture, and chemical exposure to keep the system safe and reliable. It doesn’t increase charging susceptibility; in fact, proper insulation helps minimize unwanted charging and arcing. And insulation is not optional in most wiring harnesses—it's required to ensure safe, dependable operation.