Herewith are a few 1999 National Electrical Code (NEC) changes you may have overlooked.
In Sec. 210-52(b)(1) Exception No. 2, and 220-16(a) Exception, a separate 15-ampere or larger single-outlet branch circuit is permitted for the refrigerator in the kitchen of a dwelling unit, but no additional load is to be calculated for this outlet.
Sec. 210-60 says that, in guestrooms of hotels and motels, at least two of the receptacle outlets shall be readily accessible. (The 1996 NEC required them all to be readily accessible). Where located behind the bed, a receptacle shall be guarded or so located that the bed will not contact a plug installed in it.
Sec. 300-4 (b)(1) calls for bushings or grommets in steel studs to protect nonmetallic sheathed cable running through the stud openings to cover all of the raw edges of the metal stud. In other words, the grommet must totally surround the cable, protecting it against raw metal edges at the top as well as at the bottom. Some of these plastic protectors that were formerly only at the bottom of the opening allowed the cable sheath to be damaged while it was being pulled through the studs.
Electricians will welcome the 1999 NEC change in Sec. 300-14 regarding outlet, junction, and switch boxes where the dimensions of the face opening are less than 8 inches in any direction. The previous (1996 NEC) requirement, for 6 inches of free conductor at each outlet, has been expanded to clarify that the 6 inches is to be measured from in the box where the conductor leaves the raceway or the cable sheath. In addition, the conductors shall be long enough to extend 3 inches beyond the face of the box. These requirements will prevent the skinning of many knuckles. Where the box opening is 8 inches or larger it allows the hands to work inside the box and these longer wires are not necessary.
There is an exception for conductors feeding through the box without splice or termination, which is common in raceway work. However, it is wise to leave a big enough loop of wire at the back of the box so that it can be worked on later.
Temporary wiring, except where installed for emergencies and for tests, experiments, and developmental work, had to be in multiconductor cord or cable assemblies under the 1996 NEC. That ruled out single conductor wiring and festoon lighting, common for Christmas tree lots, pumpkin lots, and other holiday uses, but that unreasonable restriction has been eliminated in the 1999 NEC, Sec. 305-4(c). The 1993 NEC restrictions have also been restored for single conductor branch circuits: not over 150 volts to ground; protected from physical damage; and supported on insulators not over 10 feet apart.
To take advantage of the higher ampacities for feeder conductors for dwelling units in Table 310-15(b)(6) [Old Note 3] the “main power feeder” is now described as “the feeder(s) between the main disconnect and the lighting an appliance branch circuit panelboard(s).”
The intent is to limit the application of the Table to the feeder for the load representing the known diversity in dwelling units. Just why the feeder and panelboards are appended with an “(s)” is difficult to understand, for only one panelboard in a dwelling unit could possibly supply the usual lighting and small appliance loads and represent the normal diversity that is historically present.
In Secs. 331-3(8) and 331-15, electrical Nonmetallic Tubing may now be purchased as a factory prewired assembly in sizes 1/2 inch through 1 inch in cartons, coils, or reels. Permitted encased in concrete either at or below grade level, ENT is not permitted for direct earth burial. All of the normal requirements apply, including number of wires, trimming of cut ends, bends, and support.
In Sec. 370-27(a), the long-standing practice of supplying and supporting wall bracket fixtures from a switch box is finally recognized. Many wall fixtures do not completely cover the ordinary 4-inch octagon lighting outlet box, so the device box with a 3- x 2-inch opening has long been used for this purpose. Limits of 6 lbs. or less in weight, and 16 inches or less in any dimension have been placed on the fixtures in order to be supported by two 6-32 screws.
New Part D of Article 370 provides requirements for manholes and other subsurface enclosures within which people work. Construction, access, working space, and conductor bending space are among the requirements, which closely parallel the requirements in the National Electrical Safety Code (NESC), ANSI C2, the “Utility Code.”
Sec. 410-58(a) was changed as well. A type of grounding pin on 15-ampere plugs, which could be folded out of the way so the plug could be inserted into a two-wire receptacle was recognized in the Code from 1962 to 1993. It was removed from the 1996 NEC because “it was no longer manufactured,” but it turns out that plug-in types of GFCIs use this movable, self-restoring grounding pin so for that use only it has been restored to the 1999 NEC.
SCHWAN is an electrical code consultant in Hayward, Calif. He can be reached at firstname.lastname@example.org.