Q. A conductor passing through a box unbroken counts as one conductor, so if I loop a conductor through the box unbroken and strip off enough insulation to terminate on a receptacle without cutting the wire, does the conductor count as one or two conductors for box sizing?
A. It counts as two conductors. Each conductor that runs through a box and does not have 6 inches of free conductor for splices or terminations in accordance 300.14, and each conductor that terminates in a box is counted as a single conductor volume in accordance with Table 310.16(B). If the conductor includes a loop long enough to terminate on a device legally (at least 12 inches), it must be counted as two conductors [314.16(B)(1)]. According to 300.14, at least 6 inches of free conductor, measured from the point in the box where the conductors enter the enclosure, must be left at each outlet, junction, and switch point for splices or terminations of luminaires or devices.