The 2002 National Electrical Code uses a dual system of measurements.
Most quantities and dimensions are given both inch-pound and metric units. Although U.S. construction plans and specifications use primarily inch-pound units of measurement (sometimes called English), metric units (also called SI) appear first in the 2002 Code.
There are two reasons for this:
1. To harmonize with other NFPA technical standards, which primarily use SI units.
2. To make the NEC more suitable for use in other countries around the world, nearly all of which use the modernized metric system known as the International System of Units (SI).
90.9 contains the rules the rules for units of measurement in the 2002 NEC. Important concepts include the following: What is “hard conversion?” Hard conversion means that a length, height, or other measurement is expressed in a rational quantity of metric units approximately equal to the inch-pound units that follow in parentheses.
• 250.86, Exception No. 1(b) talks about wiring methods in runs of less than 7.5 m (25 ft).
• 334.30 requires that Type NM cable be supported at intervals not exceeding 1.4 m (4-1/2 ft) and within 300 mm (12 in.) of each box, cabinet, or other termination.
In these two examples, the dimensions being converted aren’t regarded as critical for safety, and thus hard (approximate) conversions are considered acceptable. What is “soft conversion?” Soft conversion means the SI units have been mathematically converted from inch-pound units to provide an exact metric equivalent. Normally this is done where hard conversion might result in reducing a dimension that is regarded as critical for safety, or because a particular type of equipment is only available in inch-pound sizes.
• Table 110.31 specifies minimum the distances from fences to live parts at different voltage levels as 3.05 m (10 ft), 4.57 m (15 ft), and 5.49 m (18 ft). That’s because rounding the first two dimensions downward to 3 meters and 4.5 meters (i.e., hard conversion) would reduce the minimum distances below what is considered necessary for safety.
• Table 344.24 specifies the minimum permissible radii of rigid metal conduit bends in very precise metric dimensions such as 114.3 mm (4-1/2 in.), 146.05 mm (5-3/4 in.), and 209.55 mm (8-1/4 in.). That’s because conduit benders are actually calibrated in inches, so no purpose would be served by hard-converting the inch dimensions into rationale metric quantities such as 115 mm, 145 mm, and 210 mm.
Trade sizes. Sizes of raceway, fittings, and certain other items are expressed in so-called trade sizes that don’t represent true measurements. In other words, neither the inside nor outside diameter of a so-called “2-inch conduit” actually measures precisely 2 inches. Instead, 2 inches represents a nominal measurement that is close to the pipe’s actual diameter. In all previous editions of the Code, raceway and fitting sizes were expressed in inch-based measurements.
Beginning with the 2002 NEC, they are expressed in dual-unit trade sizes. Table 344.24 illustrates this clearly: each rigid metal conduit size is identified first by a ‘Metric Designator’ and second by a ‘Trade Size’ based on its traditional inch measurement. Dual designations for all sizes of conduit, tubing, and accessories are shown in Table 300.1. Wire designations are still the same.
It should be noted that the 2002 National Electrical Code doesn’t contain equivalent metric dimensions for conductor sizes. Conductors sizes are still expressed in AWG (American Wire Gauge) for sizes 27 through 4/0, and in kcmil (thousand circular mils) for sizes 250 through 2000. What about electrical units? All standard electrical units used in the NEC such as volts, amperes, volt-amperes, kilowatts, ohms, farads, henries, etc. are an accepted part of the International System of Units (SI). So there is no change in these familiar quantities for the new 2002 edition. How is compliance judged? Section 90.9(D) specifically states that the conversion from inch-pound to metric units can be approximate, and that complying with either set of numbers constitutes compliance with the Code. In other words, if 110.31 requires a fence not less than 2.1 m (7 ft) high around electrical equipment operating at more than 600 volts, the authority having jurisdiction can measure its height with either an inch-foot ruler or a centimeter-meter ruler. If the fence measures either 2.1 meters or 7 feet high, it is considered to be in compliance with the requirements of NEC 110.31.
In an effort to speed up its slow building approval process, Miami-Dade County in south Florida is giving developers the option of hiring architects and engineers to review design plans and inspect projects.
After a six-month trail period, during which self-certification and private inspection will be allowed only for commercial construction, the county will consider expanding the program to include residential occupancies. The so-called ‘affidavit ordinance’ was prompted by a new building code, which became effective January 1, 2002. Under the unified Florida Building Code, local jurisdictions can establish procedures for private plan reviews and inspections. The decision has proved controversial.
Charles Danger, director of the county’s building department, has expressed concern that there are no procedures in place to handle requests for private plan reviews and inspections. He also observed that design professionals who issue permits and check buildings will expose themselves to costly potential liability. While county inspectors can’t be sued for a bad inspection, privately hired architects and engineers can be. Others are concerned about inherent conflict of interest. “Nobody on our side of the table wants this,” asserts D.R. ‘Rod’ Borden, a Miami electrical contractor and past president of NECA. “It’s wrong to have the same people inspect the buildings who design them. Privatization is not good for the industry.”
To provide some safeguards, Miami-Dade plans to have county building officials review 20 percent of all privately certified plans and 50 percent of all private on-site inspections. The measure also allows the building department to revoke building permits, and decertify design professionals. According to Rod Borden, the real delays aren’t caused by field inspections, which he says are working pretty smoothly, but by the plan review process.
“Our biggest bottleneck is between fire department review and electrical review,” he says. “Plans bounce back and forth between the two sections and sometimes it’s very difficult to find out what the permit status is.” Supporters of the new initiative point out that privatization has worked well elsewhere in the country. In New York City, whose certification program served as the model for the Miami-Dade ordinance, more than 20,000 building permits have been issued using private plan reviewers and inspectors, with only 50 alleged violations reported.
The state of Washington has begun levying fines of up to $5000 against companies that install or maintain electrical equipment without an electrical contracting license.
The new enforcement campaign by the state’s Department of Labor and Industry is particularly aimed at property management companies that often use unlicensed building operators and engineers to perform routine electrical maintenance tasks such as replacing wall switches. The state started contacting violators in January of 2001. It allowed some on-the-job training to replace certain licensing requirements, and some relevant work experience could be ‘grandfathered in’ until December 31.
But now the state is requiring those who do electrical work without proper credentials to obtain electrical contractors’ licenses. “We’ve been trying to contact people all year,” said Ron Fuller, chief electrical inspector for L&I. “Are we going into every building that has a maintenance person? No. But they are going to be much higher on our radar screen now.”
Stepping up enforcement The law requiring electrical work to be performed by licensed contractors dates from 1973 but has not been consistently enforced. Steve Washburn, executive director of NECA’s Puget Sound Chapter, was previously a lobbyist who helped push the measure through the state legislature. “There was an exemption in the law that permitted electrical work in owner-occupied buildings — both residential and commercial — to be performed by owners or their employees. But if a building is for rent, sale, or lease, then you’re required to use licensed contractors employing certified electricians,” explains Washburn. “NECA and IBEW have been pressuring the Department of Labor and Industry to be more aggressive in enforcing this public-safety requirement.
Right now, you’ve got unqualified people performing electrical construction and maintenance work all over the state.” Fines against firms that perform electrical work without proper license will be $500 for the first offense, escalating to as much as $5000 for repeated infractions. The state also will fine electricians or apprentices who don’t hold proper documents, and crack down on firms that employ electricians and apprentices in improper ratios. To avoid paying fines and bring employees into compliance while they could still receive credit for previous work experience, roughly half of an estimated 10,000 violators statewide entered licensing training programs during 2001.
States all around the country are decisively rejecting the so-called ICC Electrical Code.
Massachusetts and North Carolina were the first states to adopt the 2002 edition of the National Electrical Code. Kansas, Nebraska, and North Dakota are the most recent ones that have voted to continue using the NEC. The International Code Council (ICC), an organization of non-electrical building officials, is promoting its own electrical document — actually a 25-page booklet of administrative procedures plus a handful of wiring rules — as part of its International Building Code (IBC) series of publications. But to date, most states are steering clear.
“I don’t think it’s any mystery why most jurisdictions are choosing to stick with the NEC,” suggests Mark Earley, assistant vice president for electrical engineering at the National Fire Protection Association (NFPA). “The NEC is a complete code. It covers the full range of applications you find in commercial, industrial, and residential occupancies. “The 2002 NEC also contains a new Article 80 on administrative requirements for adopting and enforcing an electrical code. That’s another important reason why there’s no need for a separate code of administrative provisions.”
An ongoing educational process D.L. Smith, a Topeka electrical contractor and long-time member of the Kansas Building Advisory Board, was instrumental in helping convince that state’s Division of Architectural Services to continue adopting the National Electrical Code for regulatory use. “We explained to them that the NEC was the only national building code for electrical work, and was developed through public consensus procedures — unlike ICC’s documents, which are just written by their members. We helped them understand how important it was to maintain the integrity of this Code that has served us well for over a hundred years.”
“Making sure that states continue to rely on the NEC is more of an educational process than anything else,” comments Brooke Stauffer, director of codes and standards for NECA. “Often the building departments are headed up by political appointees, and they may not realize there’s any controversy about electrical codes unless our industry comes in and tells them: we need the NEC to guarantee public safety.” “The National Electrical Code has brought harmony and uniformity to electrical installations all over the U.S. for a century,” NFPA’s Earley observes. “And now it’s being adopted in other parts of the world as well.”
The cabling infrastructure for business communications is the backbone of the global economy.
Now the two leading organizations of network system installers have jointly published NECA/BICSI 568-2001, Installing Commercial Building Telecommunications Cabling (ANSI). It becomes the fourteenth volume of the “National Electrical Installation Standard” series of publications. It covers five major subjects: pulling cable, support systems, firestopping, cable terminations, and installation verification. Tables and figures include conduit bending radii, separation distances, cable tray installation details, firestopping, cabling schemes, and more. As an organization accredited by the American National Standards Institute, NECA provided the necessary expertise to gain ANSI approval for the new joint publication.
“The consensus process that we go through means that NECA/BICSI 568 is a true industry standard,” explains NECA CEO John M. Grau. “We expect it to find broad acceptance among specifiers and end-users of voice-data-video networking systems.” “This document covers the installation and safety requirements for telecommunications cabling, and focuses on delivering performance levels expected by end-users,” said Jay Warmke, BICSI executive director. “It will be a valuable tool for the construction industry, including architects and engineers, and especially the installers of the telecommunications cabling.”
Ordering information. NECA/BICSI 568 costs $25 with NECA-member and quantity discounts available. Contact the NECA Order Desk at (301) 215-4504 tel, (301) 215-4500 fax, or firstname.lastname@example.org. Provide your name, company, mailing address and NECA member number (where applicable). All non-member orders must be prepaid by check or credit card.
Articles by and about NECA Codes and Standards have appeared recently in the following publications:
T.E.D. (The Electrical Distributor), “Reality Check for VDV Systems,” January 2002 Electrical Contractor (EC),
“Fuel Cells Now: An Update,” January 2002 EC,
“States Reject ICC Electrical Code, Accept NEC,” January 2002 T.E.D.,
“What Do Contractors Think About Their Voice-Data-Video Distributors?” December 2001 EC,
“Industry Tells ICC: ‘Don’t Mess With Our Code’,” December 2001 www.construction.com,
“NECA Makes Case for Expanded Division 16 Before CSI Task Team,” November 12, 2001 T.E.D.,
“The Other Low-Voltage Systems,” November 2001
New chair for NEC-Technical Correlating Committee
James Carpenter has been appointed chair of the National Electrical Correlating Committee. Carpenter is the Chief Electrical Engineer/State Electrical Inspector for the North Carolina Department of Insurance. Since 1984 he has represented the International Association of Electrical Inspectors (IAEI) on Code-Making Panels; served as chair of CMP-2 from 1992 to 2001; and was a member of the NEC Task Group on Usability.
2002 Canadian Electrical Code published
The 2002 edition of the Canadian Electrical Code, Part I, is now available from the Canadian Standards Association (CSA) at (416) 747-4000. The CEC, Part I is Canada’s book of wiring rules, roughly equivalent to the NEC in this country. Part II of the CEC is a collection of CSA product safety standards similar to those published by Underwriters Laboratories Inc. (UL), but for use in Canada.
TIAs and Errata for NFPA standards available online
Tentative Interim Amendments (TIAs) and Errata for standards published by the National Fire Protection Association are available online. Users of NFPA codes and standards should visit www.nfpa.org/codes/tias___errata.asp and download or print out changes to the documents they are concerned with, to make sure of having the complete approved text.
NFPA issues lightning protection standard
The NFPA Standards Council has approved publication of the 2000 edition of NFPA 780, Standard for the Installation of Lightning Protection Systems. Its release had been delayed for more than a year due to a long-running dispute about the scientific basis for lighting protection standards. For more background information on this subject see the November 2000 and August 2001 issues of Contractors’ Code Letter.
First woman named to head up IEEE-USA
LeEarl Bryant, a licensed professional engineer from Richardson, Texas, became the first woman to serve as president of IEEE-USA, beginning January 1. The Institute of Electrical and Electronics Engineers is a transnational professional society, and IEEE-USA its largest national division.
IALD accepting entries for lighting awards
The International Association of Lighting Designers is now accepting entries for its 19th Annual International Lighting Design Awards, co-sponsored by Architectural Lighting magazine. Anyone is eligible to enter; projects must be a permanent interior or exterior lighting solution that was completed after June 1, 1999. Entries are due by February 1, 2002 and awards will be presented at the LightFair International trade show being held in San Francisco this June. For more information contact the IALD Awards Program at (312) 527-3677 tel, (312) 527-3680 fax, or email@example.com.
UL launches new mark
Underwriters Laboratories Inc. (UL) has introduced a new performance verification mark for telecommunications cabling products. It indicates that copper and optical fiber cables have been certified for safety, and for compliance with industry performance standards such as TIA/EIA 568-A, ISO/IEC 11801, NEMA WC66, and Telcordia.
“The new verification mark clearly identifies products evaluated for transmission performance, in order to meet the unique needs of the communications cabling industry and user community,” explained Steve Galan, UL’s global program manager for wire and cable.
When used on listed communications cables, the UL Performance Verification Mark is placed adjacent to listing information such as the manufacturer’s name, product type, and issue number. The UL Performance Verification Mark can also be applied to non-listed copper and fiber cables, to indicate conformance with industry performance specifications only.
Upcoming meetings of interest to the codes & standards community:
Jan 9–11: NFPA Standards Council, Ft. Lauderdale, FL
Jan 31–Feb 1: ANSI Board of Standards Review (BSR), Ft. Lauderdale, FL
Feb 18–20: NFPA 70E, Electrical Safety Requirements for Employee Workplaces, Indialantic, FL
Feb 27–Mar 1: NFPA Technical Committee on Telecommunications, San Francisco, CA
Feb 27–Mar 1: NFPA 497, Electrical Equipment in Chemical Atmospheres, San Francisco, CA
May 2: ANSI Board of Standards Review (BSR), New York, NY