Most local codes follow the NEC, but there can be variances. The local code always takes precedence over the NEC when there are differences, so be sure to check with your local building department for the specific code requirements for your situation. Much of the NEC involves requirements for general electrical installation that apply to all situations, but there are also specific requirements for individual rooms.
Bathrooms
Because of the presence of water, bathrooms have very carefully defined requirements. With their lights, vent fans, and outlets that may power hairdryers and other appliances, bathrooms use a lot of power and may need more than one circuit.
The outlet receptacles must be served by a 20-amp circuit. The same circuit can supply the entire bathroom (outlets plus lighting), provided there are no heaters (including vent fans with built-in heaters) and provided the circuit serves only a single bathroom and no other areas. Alternatively, there should be a 20-amp circuit for the receptacles only, plus a 15- or 20-amp circuit for the lighting. Vent fans with built-in heaters must be on their own dedicated 20-amp circuits. All receptacles in bathrooms must have ground-fault circuit-interrupter (GFCI) protection. A bathroom requires at least one 120-volt receptacle within 3 feet of the outside edge of each sink basin. Duel sinks can be served by a single receptacle positioned between them. Light fixtures in the shower or bath area must be rated for damp locations unless they are subject to shower spray, in which case they must be rated for wet locations.
Kitchen
The kitchen uses the most electricity of any room in the house. Fifty years ago, a kitchen might have been served by a single electrical circuit, but today, a newly installed kitchen with standard appliances requires at least seven circuits and often more.
Kitchens must have at least two 20-amp 120-volt “small appliance” circuits serving the receptacles in the countertop areas. These are for portable plug-in appliances. An electric range/oven requires its own dedicated 120/240-volt circuit. The dishwasher and garbage disposal both require their own dedicated 120-volt circuits. These can be 15-amp or 20-amp circuits, depending on the electrical load of the appliance (check the manufacturer’s recommendations; usually 15-amps is sufficient). The dishwasher circuit requires GFCI protection, but the garbage disposal circuit does not—unless the manufacturer stipulates it. The refrigerator and microwave each require their own dedicated 120-volt circuits. The amperage rating should be appropriate to the electrical load of the appliance; these should be 20-amp circuits. All countertop receptacles and any receptacle within 6 feet of a sink must be GFCI-protected. The countertop receptacles should be spaced no more than 4 feet apart. Kitchen lighting must be supplied by a separate 15-amp (minimum) circuit.
Living Room, Dining Room, and Bedrooms
Standard living areas are relatively modest power users, but they have clearly defined electrical requirements. These areas are generally served by standard 120-volt 15-amp or 20-amp circuits that may serve more than one room.
These rooms require that a wall switch is placed beside the entry door of the room so that you can light the room upon entering it. This switch can control either a ceiling light, a wall light, or a receptacle for plugging in a lamp. The ceiling fixture must be controlled by a wall switch rather than a pull chain. Wall receptacles may be placed no farther than 12 feet apart on any wall surface. Any wall section wider than 2 feet must have a receptacle. Dining rooms usually require a separate 20-amp circuit for one outlet used for a microwave, entertainment center, or window air conditioner.
Stairways
Special care is needed in stairways to ensure all of the steps are lighted properly to minimize the hazard fo falling.
Three-way switches are required at the top and bottom of each flight of stairs so that lights can be turned on and off from both ends. If the stairs turn at a landing, you may need to add additional lighting fixtures to make sure all areas are illuminated.
Hallways
These areas can be long and need adequate ceiling lighting. Be sure to place enough lighting so shadows are not cast when walking. Remember, hallways often serve as escape routes in the event of emergencies.
A hallway over 10 feet long is required to have an outlet for general purpose use. Three-way switches are required at each end of the hallway, allowing the ceiling light to be turned on and off from both ends. If there are more doors served by a hallway, such as for a bedroom or two, you may want to add a four-way switch near the door outside of each room.
Closets
Closets come with many rules regarding fixture type and placement.
Fixtures with incandescent light bulbs (which get very hot) must be enclosed with a globe or other cover and cannot be installed within 12 inches of any clothes storage areas (or 6 inches for recessed fixtures).Fixtures with LED bulbs must be at least 12 inches from storage areas (or 6 inches for recessed).Fixtures with CFL (compact fluorescent) bulbs may be within 6 inches of storage areas.All surface-mounted (not recessed) fixtures must be on the ceiling or the wall above the door.
Laundry Room
The electrical needs of a laundry room will vary, depending on if the clothes dryer is electric or gas.
A laundry room needs at least one 20-amp circuit for receptacles serving laundry equipment; this circuit can supply a clothes washer or a gas dryer.An electric dryer needs its own 30-amp, 240-volt circuit wired with four conductors (older circuits often have three conductors).All receptacles must be GFCI-protected.
Garage
As of the 2017 NEC, newly constructed garages need at least one dedicated 120-volt 20-amp circuit that serves only the garage. This circuit may also power receptacles mounted on the exterior of the garage.
Inside the garage, there should be at least one switch controlling lighting. It is recommended that three-way switches be installed for convenience between the doors.Garages must have at least one receptacle, including one for each car space.All garage receptacles must be GFCI-protected.
Additional Requirements
AFCI requirements. The NEC requires that virtually all branch circuits for lighting and receptacles in a home must have arc-fault circuit-interrupter (AFCI) protection. This is a form of protection that guards against sparking (arcing) and thereby reduces the chance of fire. Note that the AFCI requirement is in addition to whatever GFCI protection is required—an AFCI does not replace or eliminate the need for GFCI protection. AFCI requirements are enforced mostly in new construction—there is no requirement that an existing system must be updated to comply with new-construction AFCI requirements. However, as of the 2017 NEC revision, when homeowners update or replace failing receptacles or other devices, they are required to add the AFCI protection at that location. This can be done in several ways:
A standard circuit breaker can be replaced with a special AFCI circuit breaker. This is a job for a licensed electrician. Doing so will create AFCI protection for the entire circuit. A failing receptacle can be replaced with an AFCI receptacle. This will create AFCI protection to only the receptacle being replaced. Where GFCI protection is also required (such as kitchens and bathrooms), a receptacle can be replaced with a dual AFCI/GFCI receptacle.
Tamper-resistant (TR) receptacles. All standard receptacles must be tamper-resistant (TR) type. These include a built-in safety feature that prevents children from sticking items into the receptacle slots.
