Residential Electrical Code Requirements

NEC house code requirements address outlets, boxes, grounding, GFCI and AFCI protection and other parts of residential electric systems. Local codes usually follow the NEC but can have variations for residential electric wiring. Always check with the building department of your municipality before doing electrical work.

All lighting must be on either a 15-amp or 20-amp circuit. The 15-amp circuits should use 14-gauge wire while 20-amp circuits should use 12-gauge wire.

The code does not set required heights for wall outlets or light switches but does require wall-mounted control devices to be located near the room entrance. Most Pros follow the industry standard for common residential measurements, even when not required by electrical codes:

• Standard wall receptacle height is 1 foot from the top of the flooring to the bottom of the receptacle box, or 16 inches to the top of the box.
• Standard wall switch height is 4 feet from the top of the flooring to the bottom of the box.

Metal boxes are required when using metal raceways to run wiring, both as an anchor for the conduit and to ground the system.

Either metal or plastic boxes can be used with non-metallic cable secured to the box with the appropriate clamp.

All appliances and receptacles must attach to a ground wire or metal sheathing that runs to the service panel. This includes appliances with three-prong plugs.

• When using plastic boxes, connect the ground wire to just the receptacle.
• When using metal boxes, attach ground wires to both the receptacle and to the box with a grounding screw.

Residential branch circuits for receptacles and lighting must have AFCI protection. AFCI protection is required in new construction and when old systems are updated or replaced.

NEC 2023 requires that, in residential spaces where unqualified persons can readily access the means to disconnect an air conditioner, the disconnect enclosure or the hinged door that exposes energized parts must be capable of being locked or require a tool to be opened.

In addition, feeders supplied to one and two-family dwelling units must have outside emergency disconnects that are clearly labelled. This allows first responders to disconnect power on the outside of a dwelling in case of emergency.

Pro Tip: For more on electrical grounding, read our guide, “How & Why to Ground Wiring.”

Kitchens use the most electricity of any room in the house. In new builds, kitchens require a minimum of eight circuits.

Kitchen lighting must be provided by a separate circuit of 15 or 20 amps.

GFCI protection for appliances includes dryers, wall-mounted ovens, counter-mounted cooking units and microwave ovens. NEC 2023 also requires GFCI protection for any cord- and plug-connected appliance in kitchens, not just on countertops.

A GFCI update removes the distance limitation between kitchen receptacle outlets and the sink. All receptacles in kitchen now need GFCI.

Electric ranges require 240-volt, 50-amp circuits.

The following appliances require individual 120-volt branch circuits:

• Dishwashers, 15- or 20-amp circuits depending on the electrical load, GFCI protection required
• Garbage disposals, 15- or 20-amp circuits depending on the electrical load, GFCI protection required
• Refrigerators, 20-amp circuit, GFCI protection required
• Built-in microwaves, 20-amp circuit that can be shared with another appliance

Kitchen wall receptacles, like all receptacles in a dwelling, must be tamper-resistant unless they are more than 5 1/2 feet above the floor and not blocked by a heavy appliance such as a refrigerator.

Countertops must have at least two 120-volt, 20-amp branch circuits serving the outlets for small appliances. The receptacles should be GFCI and AFCI-protected and no more than 4 feet apart.

For counter spaces more than a foot long, a GFCI receptacle is required, and no part of the countertop can be more than 2 feet from a receptacle. The maximum space between countertop outlets is 4 feet.

Kitchen islands with countertops more than 2 feet wide or long must have at least one receptacle installed for the first 9 square feet, and one installed for each additional 18 square feet of countertop. Kitchen island countertop receptacles must be pop-ups installed in the countertop surface, not under the edge of the countertop.

Pro Tip: A duplex receptacle is two receptacles on one yoke.

Bathrooms can have high demand for electricity due to the use of such appliances as hair dryers. Bathrooms also need special protection due to the presence of water.

Bathrooms must have at least one 120-volt receptacle within 3 feet of the outside edge of each bathroom sink basin. Double bowl sinks can be served by a single receptacle between them.

All receptacles must have GFCI protection and be served by a 20-amp circuit.

Bathroom outlet receptacles can be served by a single 20-amp circuit, as long as it serves no other areas, and the bathroom has no heaters.

Vent fans with built-in heaters must have an individual 20-amp branch circuit.

Light fixtures located within 3 feet horizontally and 8 feet vertically from the top of a bathtub or shower must be rated for damp locations. If they are subject to shower spray, they must be rated for wet locations. Bathroom light fixtures should have sealed globes or another design to keep out moisture.

Laundry rooms often have multiple circuits:

• Laundry rooms must have at least one 20-amp circuit for receptacles serving washing machines or gas dryers. The lighting circuit must not be connected to the 20-amp laundry circuit.
• Electric dryers require their own 30-amp, 240-volt circuit with four conductors.
• All laundry room receptacles must have GFCI protection.

According to the residential electrical code book, the following requirements apply to the other rooms in a residence. Many rooms are required to have lighting for safety.

Standard 120-volt, 15-amp or 20-amp circuits can serve bedrooms, living rooms and other rooms that usually require less electricity. These circuits can serve more than one room.

Standard living areas require wall switches next to the entry doors to control either a wall light, ceiling light or receptacle for plugging in a lamp.

Living areas require wall receptacles no farther than 12 feet apart. Any section of a wall wider than 2 feet requires a receptacle.

Dining rooms usually require a separate 20-amp circuit for an outlet that can be used for microwaves, window air conditioners or other appliances.

Stairways require three-way switches at the top and bottom of each flight of stairs so lights can be turned on or off at either end. Additional lighting fixtures may be needed if the stairs turn at a landing.

Hallways more than 10 feet long must have outlets for general use. Three-way switches are required at each end to turn a ceiling light on and off.

Garages require at least one 120-volt, 20-amp circuit with GFCI protection and at least one switched lighting outlet that cannot be connected to the 20-amp garage circuit.

Closets do not require light fixtures, but light fixtures in closets have special safety requirements:

• Closet light fixtures with LED or incandescent bulbs cannot be within 12 inches of any clothes storage area. Recessed light fixtures cannot be installed within 6 inches of clothes storage. Incandescent bulbs must be enclosed in a globe or cover.
• Closet fixtures with CFL bulbs may be within 6 inches of storage areas.
• All surface-mounted closet fixtures must be on the ceiling or the wall above the door.

The following are frequently asked questions about the electrical wiring code.

How do I know if a home’s electrical wiring is up to code?

Homes built in the past 20 years should be up to code. Newer homes may not be up to code if they’ve had unlicensed electrical work done. Older homes with no GFCI outlets are probably not up to code.

What are the electrical code requirements for circuit breaker panel boxes?

Circuit breaker boxes must be installed at a minimum height of 4 feet and a maximum of 6 feet 7 inches (79 inches). They cannot be located in bathrooms and must be accessible without lifting or moving obstructions. They should have 3 feet of clearance, and the doors should open 90 degrees without obstacles.

How many outlets are allowed per circuit?

The electrical code for outlets does not limit the number per circuit. One 15-amp circuit can supply up to 600 square feet and a 20-amp circuit can supply up to 800 square feet for lighting and receptacles. The electrical code for outlets requires that no one cord-and-plug-connected piece of equipment can exceed 80% of the breaker.

Can receptacles and lights be on the same circuit?

Electrical codes allow lights and power outlets to be on the same circuit. Electricians suggest putting no more than 8-10 lights or outlets per 15-amp circuit breaker.

How many circuit breakers should a house have?

The average number of breakers for average-sized house is 20-30. Electrical panels must have circuit directories on the outside of the panel door. Labels must identify the use of every circuit and circuit modification.

Where is surge protection required?

All service replacements or new installations require that a surge protection device be installed at the service panel.

What is the most common electrical code violation?

The most common electrical code violations are incorrect circuit breakers, insufficient electrical bonding, insufficient receptacles and outdoor receptacles that are not sufficiently covered.

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