conductors spliced in the box, two 12 AWG conductors terminating to a receptacle, and one 12 AWG equipment bonding jumper from the receptacle to the box. A. 18.50 cu in. B. 22 cu in. C. 20 cu in. D. 21.75 cu in. 14) When determining the number of conductors in a box fill that has two 18 AWG fixture wires from a domed luminaire, Electrical Box Fill Table Information. Box Fill Guidelines: No matter how many ground wires, they only count as one conductor in the box. A wire running through the box counts as one wire. Each wire coming into a splice connector is counted as one wire. Each wire connecting to a device counts as one wire of that size.