The Electrical Rough-In

The plans, as usual, guide the work. For the electrician, there'll be a separate drawing that will map out the location of every switch, plug receptacle, and light fix­ture. Special-purpose circuits such as for an electric range in a kitchen, a room-size air conditioner in a bedroom, a clothes dryer, or other appliances will also be indicated.

The size of the lines required will be specified. For light fixtures, 15 amperes is usually adequate; for plugs, 20 amps is preferable. (In simple terms, amperes or amps are a measure of the power or flow of electricity; the number of volts identifies the rate; and watts are the power actually used). An air conditioner might require 30 amperes at 240 volts (rather than the 120 volts needed for powering your toaster or bedside lamp). An electric wall oven might need 50 amps at a voltage of 240. Most major devices (like a water pump, hot water heater, furnace, range, or refrigerator) have separate lines (dedicated circuits) with separate breakers.

The anticipated electrical load on a given circuit will dictate the size of the wire required. But the plans and specifications will determine for the electricianthe wire size and the number of fixtures or receptacles on each line. It's the job of the electrician—and the electrical inspector—to ensure the wires are correctly sized and properly located.

The wires will extend from the existing electrical panel unless the remodel­ing requires that the power of your service entrance be increased. The entrance is the combination of the electrical meter outside and service  panel, typically inside your cellar or garage, where the feed lines enter from the power lines on the street. There'll be a main circuit breaker (or, in older installations, a fuse) that is the switch that controls all power entering the house. Smaller breakers or fuses then control individual circuits.