Common Electrical Codes
Before you do any kind of electrical work, you should know what codes pertain to your project because they determine how electrical work should be done.
Electricians follow the National Electric Code (NEC) to figure circuit wiring and capacity necessary for each situation. It's a fairly complex guide, so you may want to consult your local inspector for more help in clarifying codes.
As you plan out circuits, keep in mind that it's generally better and safer to have more available circuits and extra capacity, than too few.
Figure in any future updates and a maximum load demand each circuit may have when making a diagram.
Here are a few typical guidelines that do-it-yourselfers should know about when doing electrical work. These are NOT legal interpretations of the National Electrical Code, so check with your local authority before starting work:
All the kitchen, breakfast room, pantry, and dining room outlets must be supplied by at least two 20-amp small appliance circuits.
Outlets above the kitchen counter normally are fed by both circuits -- they all cannot be wired to just one circuit. The circuits should not supply any lights or other outlets in the house.
Separate circuits are needed for built-in appliances (i.e. oven, range, disposer, dishwasher, central air conditioner, furnace).
One 20-amp circuit is needed for the laundry outlet within 6' of the machines. An electric dryer requires an additional 240-volt circuit.
One lighting/convenience outlet circuit for every 575 square feet of floor space in a house.
Any bathroom or garage outlet within 6' of a sink must be GFCI protected. A new code requires all kitchen outlets for countertop use to be GFCI protected.
At least one GFCI outlet is required in an unfinished basement and for most outdoor outlets (exceptions include inaccessible outlets like at a garage ceiling or behind a refrigerator.
Any point along the bottom of a wall (which is 2' or wider) must be within 6' of an outlet. The 6' distance cannot be measured across a doorway or fireplace. And the outlet must be within 5 1/2' of the floor. This code cuts down on extension cord use, especially across doorways, fireplaces and similar openings.
A light switch must control lighting in every habitable room, hallway, stairway, or garage. The switch can control either a light fixture or a receptacle into which a lamp is plugged.
In kitchens and bathrooms, the light switch must control a permanently installed light fixture.