Frequently referred to as "the bible" of the electrical industry, the National Electrical Code (NEC), sponsored by the National Fire Protection Association (NFPA), is published every three years.
Through 20 Code Panels representing diverse segments of the electrical industry, and after an extensive and very inclusive request for comments and proposal procedure lasting two years, the Code is adopted by the NFPA. The entire Code is also recognized and adopted by ANSI (American National Standards Institute).
Since the turn of the century, the NFPA has sponsored the Code at the behest of insurance agencies and other interests. The Code is intended to safeguard people and property from hazards associated with electricity caused by improper usage. Though regarded as a national and international Code, the actual document as issued by the NFPA does not carry regulatory authority until adopted by the local governing authority. Therefore, it is an advisory document, pending the local governing body legislating the Code into law.
Enforcement is usually the domain of the authority that has enacted the NEC into law. Usually this means the municipal electrical inspector provides the interpretation of the NEC during the permit, construction, and inspection processes. The electrical inspector via the local governmental body is the local authority and can also grant exemptions to the Code, also in accordance with local procedures and customs. Due to the complexities of insurance and legal matters, once the NEC is adopted, it usually is followed completely and often with little variance from the official language, diagrams, and examples. Similarly, the Code is not a design template--instead it is a document that codifies installation of electrical systems and the types of devices based on safety considerations.
The NEC is divided into chapters--some that apply generally, and others that are highly specific. Contained within each is a structured and highly detailed system of articles that inform and clarify specific aspects of the broad category. Chapter 1 is the General introductory chapter providing definitions and basic requirements for electrical installations. Wiring and protection, including branch circuits, feeders, services, grounding, and surge arrestors are included in Chapter 2. Conduit of all types, ampacity tables, raceways and cable trays, various wire/ cable types, panel boards, switchboards, and boxes are covered in Chapter 3, Wiring Methods and Materials. Chapter 4, Equipment for General Use, has articles on flexible cords and cables, lighting fixtures and receptacles, appliances, permanent electric heating equipment, air conditioning and refrigeration equipment, motors and controllers, transformers, and generators. Chapter 5, Special Occupancies, is of special interest to the entertainment industry since it covers Theatres and Similar Locations; Motion Picture Studios; and Carnivals, Circuses, and Fairs. Chapter 6 is labeled Special Equipment, with electric signs, electric welding, audio amplification and reproduction equipment, swimming pools, solar cells, and fire pumps being among the specialized equipment in this category. Special Conditions is the domain of Chapter 7, with articles detailing emergency systems, standby power, Class 1, Class 2, Class 3, and power limited circuits, fire alarm and fiber (communications) cabling, and other types of situations. The specialized areas of Chapter 8 include Radio and Television equipment and antennas, CATV and radio distribution systems, and broadband networks and their grounding. The various tables and appendices provide more examples and other useful information, e.g. conduit capacities and conductor properties. An extensive cross reference from the 1999 NEC to the 1996 NEC is also provided for informational and reference purposes.
One of the major changes in the 1999 Code was the reorganization and rewriting of many articles. According to Mitch Hefter of Rosco/Entertainment Technology, who addressed NECchanges at an LDI98 session, "The Code Panels tried to make the Code more user-friendly. So, there are a lot of vertical bars in the text that indicate changes that didn't really change anything per se, but hopefully you'll be able to read it better and understand it."
Simply stated, the text has been rewritten to incorporate, via separate clauses, more of the items that used to be listed as separate exceptions in past Codes. This change deletes large numbers of separately listed exceptions and continues to list the item as significant to that section. There is additional "fine print" further clarifying and providing interpretation to the main text. It is important to note that a "bullet" in the margin alongside the text signifies that something was removed, as when the 99 Code is contrasted to the 96 version.
The other NEC panelist at LDI was Steve Terry of Production Arts, who, like Hefter, is a member of Code Panel 15. Ken Vannice of NSI Corp. was the USITT representative to the panel. Representing the International Association of Theatrical Stage Employees (IATSE) was Eddie Kramer of Radio City Music Hall, while the Illuminating Engineering Society of North America (IESNA) representative was Michael Klein of Labyrinth Electrical. Hefter is the new IESNA representative. As explained in great detail at the LDI98 seminar, the mission of a Code Panel is to review publically submitted proposals regarding the articles under its jurisdiction, with the goal of improving the safety of electrical installations while continuing to allow for changing technology and usage requirements. There are 20 Code Panels that form the NEC committee. A coordinating committee unifies the process and the entire document is voted on and adopted by the NFPA. As noted previously, the Code is advisory until adopted by municipalities, a practice that takes anywhere from three months to a year. Then the cycle, a three-year process, begins again.
Encompassing hundreds of changes, the task of explaining each one is beyond the scope of this article. But the NFPA publishes "NEC Changes," a thorough and comprehensive document with the changed article listed on a separate page with explanatory diagrams and accompanying text, including the new text, which is shown in bold type.
Many articles in Chapter 5 (Special Occupancies) pertain to readers of Lighting Dimensions. Article 518--Places of Assembly is brief, but the wording (and examples) has been revised to clearly pertain to "rooms that have 100 people or more. It doesn't matter whether the 100 people are in armories, assembly halls, auditoriums, or other places," says Vannice, who at LDI stressed that this definition is central to understanding this article and subsequent ones that relate to special usage environments. At the panel, Steve Terry explained, "The added wording in section 518-2, 'including associated seating areas,' is a powerful change to the Code. If we have a room in a place of assembly that's a theatrical area, the audience seating area is also covered by Article 520." This means that plastic conduit wiring methods allowed in Places of Assembly may not be used in these theatrical areas.
Article 520 has a significant change in 520-53 (k) regarding Cam-Lok and similar single-pole separable connectors. New wording added in 1999 states that other articles of the NEC (400-10 and 410-56) do not apply to these connectors. The central issue is mechanical strain relief and intermateability between connectors of different amperages. The new Code should preserve the usage of Cam-Loks which are required to be installed by qualified personnel. This wording should prevent misapplication of other Code sections to single-pole connectors.
Continuing to clarify language and therefore allow for easier application of the Code nationwide, the use of junior hard service cords (hard usage rather than the extra-hard usage generally required in theatres) for construction of twofers is now permitted. A twofer is an adapter, consisting of one male plug with two female connectors, that is usually not exposed to hard use environments and is installed near the lighting instruments or mounted to a support structure. Type SJ, SJO, SJTO, and similar conductors are now permitted.
According to Terry, "in a previous Code cycle, the use of junior hard usage cord was allowed for breakout assemblies, so it's been extended to twofers and other adapters." The impetus was the difficulty of wiring a twofer with two type SO extra-hard usage conductors into a standard plug. Bob Luther of Lex Products explains, "The use of junior hard usage cord allows the manufacture of twofers that are smaller, more flexible, and more economical than those made of extra-hard usage cord. There will be a large cost savings and convenience, without a compromise to safety through the use of junior hard usage cord." Twofers made using junior hard service cord will be limited to an overall length of 3.3' (1m). These changes are delineated under Article 520-69--Adapters. In summary on this aspect, only in specialized instances (both amperage and length) can the junior hard usage-type cords be used, and there are maximum lengths permitted.
Dressing rooms are another area that benefits from changes incorporated into the 1999 NEC. Article 520-73 revises the requirements for receptacles in these spaces. Only those receptacles adjacent to or near makeup mirrors need to be controlled by a central switch, with a pilot light located outside the dressing room, for indication of the circuit being on. The intention is safety--in this case dryers, coffee pots, and other appliances being left on, and the risk of fire being a significant concern. Through this modification, refrigerators and other electrical devices may be used without being subject to power interruption.
There are other articles of the Code with significant relevance to readers of Lighting Dimensions. Article 400-9 is a revision, clarifying that flexible (extension) cords are not permitted to be routed through holes and in the space above a suspended ceiling, as frequently done in restaurants, retail, and in commercial office spaces. Contained within Articles 520-53 (h) and (k), feeder cables and their routing, and the use of parallel feeder cables, are clarified. Article 525--Carnivals, Circuses, and Similar Events, has many changes regarding the use of GFCI protection, clearance of overhead conductors, the types of cord connectors and their proximity to the ground, and so on.
Related to grounding, Article 640--Sound Recording and Similar Equipment, has been totally revised. The use of a "technical power system" and isolated ground is now permitted. In addition, equipment needs to be indicated as to the specific class of wiring required, and the use of Class 1, Class 2, and Class 3 wiring methods are defined. Essentially, obsolete references have been removed.
The NEC can be purchased by contacting the NFPA by phone at 800/344-3555 or 617/770-3000, or by fax at 617/770-3500. The number for the NFPA International Department (in Spanish) is 617/984-7700; fax is 617/984-7777.
Proposing changes is easy and well documented, with timely announcements in leading trade magazines including Lighting Dimensions, and postings on the NFPA website at www.nfpa.org. According to the documents and timetable released by the NFPA, the process for the development of the 2002 NEC begins this fall. Since the entire process takes approximately 90 weeks, it's time to get started.