With five different wiring methods installed in this box, including two electrical metallic tubings, two rigid nonmetallic conduits, one nonmetallic sheathed cable (Type NM-B), two surface metal raceways, and two Type AC cables, there is just not enough free space in this 4 inch x 1 1/4 inch square box. If we considered conductors sized at 12 AWG for each circuit, with two wires in each raceway, and cable, including an equipment grounding conductor in the RNMC and NM-B cable, we would end up with a total of 18 of the 12 AWG conductors, plus one additional for the three equipment grounding conductors, for a grand total of 19 conductors. As per Table 314.16(A), the maximum number of 12 AWG conductors allowed in this size metal box is only eight!

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