How many cubic inches is a standard rating for a No.18 fixture wire?

The correct answer is the standard wire size of a No.18 fixture wire, which is rated at 1.5 cubic inches. This measurement typically relates to how much space is required for the wire itself in terms of electrical boxes or conduit fill. Understanding this rating is essential for ensuring that electrical installations comply with safety regulations and provide adequate space for wiring without overcrowding. When pulling multiple wires through a conduit or box, knowing the cubic inch rating helps electricians avoid overheating and potential electrical hazards, as crowding can lead to increased heat and decreased performance of the fixture.