Articles 210 and 410 contain general receptacle provisions. Of course, that’s not to say that receptacles are only covered in these two articles. Provisions pertaining to receptacles are covered in more than 30 other articles in the National Electrical Code (NEC).
Receptacles installed on 15- or 20-ampere branch circuits must be of the grounding type, unless installed in accordance with Section 210-7(d). [210-7(a)] Replacement of existing receptacles (whether grounding- or nongrounding-type) must comply with the provisions in Section 210-7(d)(1), (2), and (3) as applicable.
Where a grounding means exists in the receptacle enclosure, a grounding-type receptacle must be connected to the grounding conductor in accordance with Section 210-7(c) or 250-130(c).
[210-7(d)(1)] If a nongrounding-type receptacle is being replaced and the box or enclosure is grounded (or has a grounding means present within the box), a grounding-type receptacle must be used. If the receptacle enclosure is connected to the grounding electrode system, a bonding jumper can be attached from the box to the receptacles grounding terminal.
If a bonding jumper is not installed, the receptacle must have contact devices or yokes designed and listed for the purpose. [250-146(b)]
This type of receptacle establishes the grounding circuit between the device yoke and flush-type box without a bonding jumper. Caution is advised when replacing a receptacle mounted in a metal box containing an existing two-wire cable. Just because the box is metal does not guarantee that it is grounded to the grounding electrode system.
A grounding-type receptacle must also be used if a nongrounding-type receptacle is being replaced, and a grounding conductor is installed in accordance with Section 250-130(c). [210-7(d)(1)] The equipment grounding conductor of a grounding-type receptacle or a branch-circuit extension can be connected to one of the following:
1) any accessible point on the grounding electrode system as described in Section 250-50;
2) any accessible point on the grounding electrode conductor; 3) the equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates;
4) for grounded systems, the grounded service conductor within the service equipment enclosure; or
5) for ungrounded systems, the grounding terminal bar within the service equipment enclosure. [250-130(c)]
An equipment grounding conductor, complying with one of these five specifications, can be installed in a receptacle enclosure where no grounding means exists.
Where an equipment-grounding conductor is pulled into the receptacle enclosure, make sure to bond the box as well as the receptacle.
Where an equipment grounding conductor enters a metal box, the box must be grounded (or bonded) to the grounding conductor. This connection must be accomplished by means of a listed grounding device, or a grounding screw used for no other purpose. [250-148(a)] Section 250-8 prohibits using a sheet metal screw to connect the grounding conductor to the enclosure.
The location must be considered when replacing a receptacle. Ground fault circuit interrupter- (GFCI)-protected receptacles must be provided where replacements are made at receptacle outlets that are required to be so protected elsewhere in the Code. [210-7(d)(2)] This provision is applicable to both grounding- and nongrounding-type receptacles.
Over the years, GFCI requirements have changed. Prior to 1987, GFCI-protected receptacles were not required in dwelling unit kitchens. In the NEC, a new provision was added that required all 125-volt, single-phase, 15- or 20-ampere receptacles installed within 6 feet of the kitchen sink (above countertop surfaces) to have ground-fault circuit-interrupter protection for personnel.
In the 1996 edition, all dwelling unit kitchen receptacles installed to serve the countertop surfaces were required to have GFCI protection for personnel. When replacing a receptacle, a GFCI-protected receptacle may be required if the current edition of the Code now requires one for that location. Provisions pertaining to GFCI-protected receptacles are covered in Section 210-8.
For example, a homeowner wants all of the countertop receptacles in the kitchen replaced. The receptacles were first installed in 1985. Although they are grounding-type receptacles, they are not GFCI protected. Since receptacles serving kitchen countertop surfaces are among the locations listed in Section 210-8, GFCI-protected receptacles must be installed.
Where no grounding means exists within the receptacle enclosure and no grounding conductor is installed, the receptacle replacement must comply with 210-7(d)(3)(a), (b), or (c). Where replacing a nongrounding-type receptacle, another nongrounding-type receptacle can be used as the replacement. [210-7(d)(3)(a)]
Nongrounding-type or two-prong receptacles are still being manufactured. Therefore, remove the old nongrounding-type receptacle and install a new nongrounding-type one.
Where no grounding means exists within the receptacle enclosure, a ground-fault circuit interrupter-type of receptacle may be installed as the replacement for a nongrounding-type receptacle. [210-7(d)(3)(b)] Although there is no grounding means within the box, a GFCI-type receptacle is permitted as a replacement.
A GFCI receptacle not connected to a grounding means (or an equipment-grounding conductor) will still function properly. A sensor within the GFCI measures the amount of current flowing through the ungrounded (hot) and grounded conductors. A difference of approximately five milliamperes (0.005 amperes) will trip the GFCI device. Therefore, if enough current is flowing to ground and not returning back though the grounded conductor, the GFCI device will trip.
Compliance with two additional stipulations is required with Section 210-7(d)(3)(b). First, the GFCI receptacle must be marked or labeled “No Equipment Ground.” This labeling will advise the consumer that this receptacle is not connected to an equipment ground. Next, an equipment-grounding conductor must not be connected from the GFCI-type receptacle to any outlet that it supplies.
A grounding-type receptacle may be installed as the replacement for a nongrounding-type one where supplied through a ground-fault circuit interrupter. [210-7(d)(3)(c)]
This provision allows for the use of either a GFCI-type receptacle or GFCI-type breaker ahead of the grounding-type receptacle. A feed-through GFCI receptacle installed at the beginning of the circuit can supply power to grounding-type receptacles downstream. Likewise, grounding-type receptacles can be installed on an existing two-wire circuit not containing an equipment-grounding conductor, if protected by a GFCI breaker. These receptacles must be labeled “GFCI Protected” and “No Equipment Ground.”
An equipment-grounding conductor must not be connected between the grounding-type receptacles.
A GFCI tester or receptacle tester that depends upon an equipment-grounding conductor to operate will not function properly when plugged into a grounding-type or GFCI-type receptacle not connected to an equipment ground. Also, since the receptacle outlet does not have an equipment ground, the tester will show an improper connection. Therefore, proper labeling of these receptacles is imperative.
(Illustrations are available in Electrical Contractor magazine)
MILLER, owner of Lighthouse Educational Services, teaches custom-tailored classes and conducts seminars covering various aspects of the electrical industry. He is the author of Illustrated Guide to the National Electrical Code. For more information, visit his Web site at www.charlesRmiller.com. He can be reached by telephone at (615) 333-3336, or via e-mail at charles@charlesRmiller.com.