Wiring carries the power from the main box to the end switch, receptacle or fixture. Wiring can either be in conduit, metal sheathed (Bx), Rubber sheathed (Romex) or in old installations knob and tube. Wiring systems are either 2 wire or 3 wire applications, which may or may not be grounded properly. Conduit is used primarily in commercial installations. Bx cable has a ribbed metal covering to protect the wires inside of it. Romex, which is the most abundantly used type of wiring in residential construction today, has a soft rubber covering.

Your inspector will be checking the exposed wiring carefully to evaluate what alterations may be required. If your inspector finds old wiring such as knob and tube or certain types of Bx cable, he or she may recommend further evaluation by a licensed electrician. Romex wiring should not be exposed in many areas as it is soft and can be a hazard. There are different materials that wire is made of including copper, and aluminum. Copper wire when sized correctly is the most popular and best conductor for normal household electrical requirements. Aluminum wire was used in the early 70's and turned out to be a potential fire hazard. Your inspector is always on the lookout for this type of installation.

Power Supply Circuit Protectors Wiring Outlets and Fixtures
Panel Box