It seems like a strange omission, but the National Electrical Code doesn't impose any restrictions on the height of an electrical outlet above the floor. If you're installing outlets in a basement, that doesn't necessarily mean you can put them at any height you want; the local building code may have requirements, and if you need to make the basement compliant with the Americans With Disabilities Act, you'll have to consider the ADA height requirements. In the absence of requirements, electricians usually employ a rule of thumb and place the top of the outlet box 18 inches above the floor in most rooms, including basements.
Although the NEC doesn't specify outlet height, it does list other requirements for outlet placement, and you'll want to consider these when planning your rough-in:
- Each wall in a room that is at least 2 feet wide, and each hallway more than 10 feet long must have at least one outlet.
- An outlet intended for a specific appliance must be no more than 6 feet from the appliance.
- Outlets must be installed in such a way that no point on a wall is farther than 6 feet away from one.
- If a counter space is provided, and the counter is more than 12 inches wide, it must be supplied by at least one wall receptacle, and no point on the counter should be more than 24 inches from a receptacle.
In addition, at least one outlet in the unfinished part of the basement must be ground-fault protected, although, for safety, ground fault circuit interrupters are recommended for every basement outlet.
To make outlets accessible to handicapped people and those in wheelchairs, the Americans with Disabilities Act specifies a minimum distance of 15 inches from the middle of the outlet box to the floor. Some states, including California, have incorporated this requirement into the building code. In Canada, the minimum distance from the middle of the box is 14 inches. When installing an outlet over a standard countertop, the ADA mandates a maximum height above the floor of 46 inches.
When it comes to wall switches, the maximum distance from the floor to the switch allowed by the ADA is 48 inches unless it's behind a counter that is more than 20 inches wide. In that case, it's 44 inches. The minimum distance between a switch and the floor allowed by the ADA is 15 inches.
Standard Outlet Placement
To be in tune with the height requirements of the ADA and the states that incorporate the ADA requirements in their building codes, electricians have adopted a standard placement of 18 inches from the top of the outlet box to the finished floor. To conform to Canadian law, you should install the outlets 17 inches above the floor.