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.
The wattage rating information for a particular device may be on a label or imprinted on the back somewhere. If no wattage rating is displayed, the load can be calculated by multiplying the amps drawn (appliance amps) by the voltage of the circuit. If neither the amps nor the wattage ratings for a device is known, the chart below lists common household appliances and the average watts drawn for each to aid in calculating the load of a circuit.
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.
Often a wall receptacle from an upper floor can be used as a source for a new ceiling fixture below, but a switch loop must be run to a wall switch in addition to fishing the cable from the source.