What is the primary purpose of insulation around a conductor in electrical wiring?

• A. To prevent electrical conduction to unintended paths
• B. To increase current carrying capacity
• C. To reduce physical resistance
• D. To improve mechanical strength

Answer: (A)

The main idea is electrical isolation: the insulation keeps the current confined to the conductor and prevents it from taking unintended paths. By surrounding the conductor with an insulating layer, it stops the current from arcing to nearby conductors, leaking to moisture, or shocking someone who touches the wire. This containment also allows multiple conductors to run close together without shorting, since each conductor is kept at its own potential.

Insulation doesn’t primarily increase how much current the wire can carry—that depends on the conductor’s size and the cooling conditions. Nor does it reduce the conductor’s resistance, which is set by the metal and its cross-section. It also isn’t mainly about adding mechanical strength, although some protection against abrasion can come from an outer jacket.