Adopted in all 50 states, the National Electrical Code (NEC), NFPA 70, is the benchmark for safe electrical design, installation, and inspection to protect people and property from electrical hazards. NEC's internal code requirements address outlets, boxes, grounding, GFCI and AFCI protection and other parts of residential electrical systems. Local codes usually follow the NEC, but may have variations for residential electrical wiring. Always check with the construction department of your municipality before carrying out electrical work.
All lighting must be in a 15 or 20 amp circuit. 15-amp circuits must use a 14-gauge cable, while 20-amp circuits must use a 12-gauge cable. Metal boxes are required when metal pipes are used to lay the wiring, both as an anchor for the duct and to ground the system. Metal or plastic boxes can be used with a non-metallic cable attached to the box with the appropriate clamp. All appliances and receptacles must be connected to a ground cable or to a metal sheath that goes to the service panel.
This includes appliances with three-pin outlets. Residential branch circuits for receptacles and lighting must have AFCI protection. AFCI protection is mandatory in new buildings and when old systems are being upgraded or replaced. In addition, the feeders that are supplied to single-family and two-family housing units must have clearly labeled external emergency disconnections. This allows first responders to disconnect power outside a home in the event of an emergency. Kitchens consume more electricity than any other room in the house.
In new buildings, kitchens require a minimum of eight circuits. Kitchen lighting must be provided by a separate 15 or 20 amp circuit. An update to the GFCI eliminates the distance limitation between the outlets of the kitchen containers and the sink. All kitchen containers now need GFCI.
Electric stoves require 240 volt and 50 amp circuits. Countertops must have at least two 120-volt, 20-amp branch circuits that serve the outlets of small appliances. Receptacles must be protected by GFCI and AFCI and must not be 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 that are more than 2 feet wide or long must have at least one receptacle installed for the first 9 square feet and another installed for every additional 18 square feet of countertop.
Kitchen Island countertop receptacles should be pop-up windows installed on the surface of the countertop, not below the edge of the countertop. Bathrooms can have a high demand for electricity due to the use of appliances such as hairdryers. Bathrooms also need special protection due to the presence of water. Bathrooms must have at least one 120-volt receptacle less than 3 feet from the outer edge of each bathroom sink. Two-bowl sinks can be served with a single receptacle between them.
All receptacles must have GFCI protection and be powered by a 20 amp circuit. Bathroom outlets can work with a single 20-amp circuit, as long as you don't service other areas and the bathroom doesn't have heaters. Ventilation fans with integrated heaters must have an individual 20-amp branch circuit. The following requirements apply to other rooms in a residence. Many rooms are required to have lighting for safety reasons. Standard 120-volt, 15-amp, or 20-amp circuits can serve bedrooms, living rooms, and other rooms that normally require less electricity.
These circuits can serve more than one room. Standard living areas require wall switches next to the entrance doors to control a wall lamp, a ceiling lamp, or a receptacle for plugging in a lamp. Living areas require wall receptacles no more than 12 feet apart. Any section of a wall larger than 2 feet wide requires a receptacle. Dining rooms often require a separate 20-amp circuit for an electrical outlet that can be used for microwaves, window air conditioners, or other appliances. Stairs require three-way switches at the top and bottom of each flight of stairs so that lights can be turned on or off at either end.
Additional lighting fixtures may be needed if the stairs turn into a landing. Hallways that are more than 10 feet long must have outlets for general use. Three-way switches are required at each end to turn a ceiling lamp 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.
Frequently Asked Questions about Residential Electrical Code
- How do I know if a house's electrical wiring complies with the code? Homes built in the last 20 years must comply with the code. Newer homes may not be up to the code if unlicensed electrical work has been done. Older homes without GFCI outlets probably aren't up to the 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.
They cannot be placed in bathrooms and must be accessible without having to lift or move them. They must have 3 feet of free space and doors must open 90 degrees without obstacles.
- How many outputs are allowed per circuit? The electrical code on outlets does not limit number per circuit. A 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 requires that no equipment connected with cable and plug can exceed 80% of switch.
- Can receptacles and lights be on same circuit? Electrical codes allow lights and electrical outlets to be on same circuit.
Electricians suggest not placing more than 8 to 10 lights or outlets per 15-amp circuit breaker.
