After cutting the hole, put the 2x4 between the joists again and set it so the outlet box sits flush with the finished ceiling surface. Have a helper hold a board over the outlet hole to support the box and keep it at the proper level while securing it in place with two, 3 inch deck screws through each joist. If needed, metal L-brackets may be added at the corners for more support.
Hold the fixture and splice the wires together, cap them with wire nuts and fold them up into the fixture box. Slide the base plate over the wires and thread the coupler nut onto the threaded rod to push the base plate up and hold it in place. Adjust the position of the base plate by turning the coupler until it’s snug against the ceiling.
A current-carrying wire in an electrical circuit. There may be one or two hot wires in a household electrical circuit. These wires are always insulated and may be colored black or red, or in the case of some ceiling fans, the hot wire may also be colored blue.
Electric cable with spiral metal sheathing. Early armored cable, BX cable, carried two electric wires with no ground. The metal sheath served as the ground. Later versions carried an aluminum ground wire, wound in the spiral. Newer armored cable includes an insulated ground wire.