14, you must leave at least 6 inches of free conductor measured from the point where the wire enters the box, with at least 3 inches extending past the face of the box opening. If wires are too short, they may fail inspection or create hazards during. According to NEC Section 300. Meeting both the six-inch length inside the box and the three-inch extension outside the box is necessary. The foundational requirement for conductor length inside an enclosure is a minimum of six inches of free conductor for each wire. The purpose of this six-inch. The general rule for NM cable is to secure the cable within 12 inches of the box and every 4.
