Given: Six size 12 AWG conductors are spliced in a box that has no grounding wires, clamps or devices and has a flat cover. What is the mimimum trade size metal octagonal box that may be used?

Given: Six size 12 AWG conductors are spliced in a box that has no grounding wires, clamps or devices and has a flat cover. What is the mimimum trade size metal octagonal box that may be used?