Building Electrical Design Principles--Occupant Protection Requirements

Tamper-Resistant Receptacle Requirements

The NEC has required tamper-resistant receptacles be installed in all 125-V, 15- and 20-A electrical receptacles in hospital pediatric areas for nearly three decades. Recently, the NEC introduced requirements for all 125-V, 15- and 20-A electrical receptacles in new residential construction to be tamper-resistant receptacles. The move comes in an effort to better protect small children from suffering electrical burns when they accidentally insert items into conventional outlets. Products such as plastic plug-in inserts and wall plates with contact shutters are avail able for tamper resistance, but don’t meet these requirements.

There are many other settings where children may be at risk, including day care centers, children's play areas, elementary and nursery schools, doctor's offices and lobbies, and retail establishments featuring children's attire or toys. Tamper-resistant receptacles should be considered in these areas. All tamper resistant receptacles must have either the words "tamper resistant" or the letters "TR" (minimum 3/16 in or 5 mm high) on the device as a clear indication that this is a tamper resistant receptacle.

Ground Fault Circuit Protection Requirements

The NEC introduced requirements for use of GFCI in residences in 1973 when it required GFCI protection of outdoor convenience receptacles within 6 1/2 ft (2 m) of grade level. In residential installations, GFCI protection is required at all 125 V, single phase 15 A and 20 A outlets in the locations listed below. The requirements don’t apply to equipment rated at 240 V (e.g., baseboard heater, room air conditioners, welding receptacles, or other outlets that are not rated at 125 V). The NEC introduced these requirements beginning in the years listed in parentheses:

• Outdoor convenience outlets within 6 1/2 ft (2 m) of grade level (1973 edition) and revised to include all exterior convenience outlets (1993 edition)

• Bathroom convenience outlets (1975 edition)

• Readily accessible convenience outlets in garages (1978 edition), except where not readily accessible such as outlets dedicated to an overhead door opener or freezer

• Convenience outlets within 6 ft (1.8 m) of kitchen sink (1987 edition) and revised to include all kitchen convenience outlets that serve countertops, including islands (1996 edition) but not those serving fixed kitchen appliances (e.g. range and oven) and the refrigerator or freezer

• Convenience outlets in unfinished basements and crawl spaces, except laundry (1990 edition)

• Convenience outlets within 6 ft (1.8 m) of laundry, utility room, or wet bar sink (1993 edition) Other locations requiring GFCI protection on 120 V, single phase 15 A and 20 A outlets include:

• Commercial kitchens

• Restrooms in commercial, industrial, and in any other non-dwelling type buildings

• Receptacles with grade-level access and at rooftop locations

• Commercial garages

• Elevator pits

• Agricultural buildings

• Aircraft hangers

• Wet locations in health care facilities

• Boathouses, marinas, and boatyards

• Receptacle outlets on roofs (except dwelling units)

• Circuits to resistance (impedance) heating units such swimming pool, spa, hot tub, de-icing and snow melting heaters;

• Receptacle and lighting outlets near swimming pools, spas, hot tubs, and fountains

Ground Fault Circuit Protection Requirements

The NEC introduced requirements for use of GFCI in residences in 1973 when it required GFCI protection of outdoor convenience receptacles within 6 1/2 ft (2 m) of grade level. In residential installations, GFCI protection is required at all 125 V, single phase 15 A and 20 A outlets in the locations listed below. The requirements don’t apply to equipment rated at 240 V (e.g., baseboard heater, room air conditioners, welding receptacles, or other outlets that are not rated at 125 V). The NEC introduced these requirements beginning in the years listed in parentheses:

• Outdoor convenience outlets within 6 1/2 ft (2 m) of grade level (1973 edition) and revised to include all exterior convenience outlets (1993 edition)

• Bathroom convenience outlets (1975 edition)

• Readily accessible convenience outlets in garages (1978 edition), except where not readily accessible such as outlets dedicated to an overhead door opener or freezer

• Convenience outlets within 6 ft (1.8 m) of kitchen sink (1987 edition) and revised to include all kitchen convenience outlets that serve countertops, including islands (1996 edition) but not those serving fixed kitchen appliances (e.g. range and oven) and the refrigerator or freezer

• Convenience outlets in unfinished basements and crawl spaces, except laundry (1990 edition)

• Convenience outlets within 6 ft (1.8 m) of laundry, utility room, or wet bar sink (1993 edition) Other locations requiring GFCI protection on 120 V, single phase 15 A and 20 A outlets include:

• Commercial kitchens

• Restrooms in commercial, industrial, and in any other non-dwelling type buildings

• Receptacles with grade-level access and at rooftop locations

• Commercial garages

• Elevator pits

• Agricultural buildings

• Aircraft hangers

• Wet locations in health care facilities

• Boathouses, marinas, and boatyards

• Receptacle outlets on roofs (except dwelling units)

• Circuits to resistance (impedance) heating units such swimming pool, spa, hot tub, de-icing and snow melting heaters;

• Receptacle and lighting outlets near swimming pools, spas, hot tubs, and fountains

• Receptacles in temporary locations (i.e., on construction sites, carnivals, circuses, and fairs) It’s common practice to provide GFCI protection for all other wet locations and outdoor receptacles even though it may not be required.

Some types of equipment (e.g., appliances with large motors) have inherent leakage current levels that exceed the standard trip setting of a GFCI. This will cause nuisance tripping of GFCI devices. For this reason, the Code usually exempts from the requirements for GFCI protection a receptacle dedicated to a single appliance, which is not accessible for other uses. This equipment must rely on a solid grounding connection to pro vide adequate protection.

GFCI circuit breakers may be added in panelboards of older buildings to replace ordinary circuit breakers. For homes protected by fuses, the convenience receptacle or portable-type GFCI protection is highly recommended. GFCI protection should also be used whenever operating electrically powered garden equipment (mower, hedge trimmer, edger, and so on).

Circuit breakers are used as switches.

Arc Fault Circuit Protection Requirements

The NEC requires AFCIs for bedroom circuits in new residential construction (starting in January 2002). Future editions of the Code will likely expand coverage to include commercial and industrial applications such as use in fire station sleeping areas, military housing, hospitals, outpatient clinics, rest homes, retirement homes, and in other locations where extension cords or cord-connected equipment may be used and where the general occupancy may be at risk from arc faults.

Older homes with ordinary circuit breakers may benefit from the added protection against arcing faults that can occur in aging wiring systems. Buildings wired with solid aluminum conductors used in the late 1960s and early 1970s are prone to poor connections. Such building electrical systems can also be retrofitted with AFCI protection to identify faulty connections.

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