What does the outer layer indicated by 'AC' refer to?

The outer layer indicated by 'AC' refers to Armored Cable. Armored cable is a type of electrical cable that has a protective metallic sheathing designed to prevent physical damage and abrasion. This construction often consists of a spiral layer of steel or aluminum, which enhances its durability and provides an added layer of safety for electrical installations.

In various applications, armored cable is utilized in environments where additional protection is required, such as in industrial settings or underground installations. It can withstand harsh conditions and physical stresses that would otherwise damage traditional non-armored cables. Therefore, understanding that 'AC' signifies Armored Cable highlights the function and importance of this type of electrical wiring in ensuring safety and reliability in power production and distribution scenarios.