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Making Amendments

Oct 1, 2007 12:00 PM, By Beck Ireland, Staff Writer

The controversy over the continued inclusion of selective coordination provisions in the NEC

Although the three-year Code-making cycle for the 2008 edition of the National Electrical Code (NEC) recently closed, the dust has not yet settled on the decision to reaffirm the inclusion of selective coordination for emergency and legally required standby systems.

While not in opposition to selective coordination itself, opponents of the controversial provisions in the NEC continue to seek relief from selective coordination as a national mandate. Although some municipalities, such as New York and Chicago, have required selective coordination under a different name for years, some states, such as Washington, plan to open these provisions up for discussion — and possible amendments — before adopting the 2008 NEC. Massachusetts, for example, already voted in an amendment to the provisions, which will be effective Jan. 1, 2008.

Selective coordination regarding phase devices first appeared in the NEC in 1993 under the jurisdiction of Sec. 620.51, governing total selective coordination for elevator systems. It was then relocated to 620.62 in 1996. Aside from this requirement for elevator circuits, professional engineers have been largely guided by NFPA 110, “Standard for Emergency and Standby Power Systems,” and IEEE Standard 242, “Recommended Practice for Protection and Coordination of Industrial and Commercial Power Systems,” which recognize selective coordination as a design consideration — not a requirement — that may maximize power reliability for both normal and emergency power systems. Licensed professional engineers were given the latitude to determine the course for maximum power system reliability dependent on the given facility's size and occupancy needs as well as installation costs. Then, in 2005, total selective coordination was adopted for NEC Secs. 700.27 (emergency systems) and 701.18 (legally required standby systems), as well as in 517.26 (essential electrical systems of health-care facilities) through the association of the life-safety branch as defined in 517.2 with Art. 700.

Since the 2005 inclusion, the debate over the efficacy of total selective coordination for emergency and standby systems remains unresolved, with the biggest flare-ups taking place during the proposal and comment phases of the most recent Code cycle. The main arguments against the Code requirements for selective coordination in emergency and standby systems are increased installation costs and the difficulty of implementation and enforcement. While there is no argument that selective coordination does improve reliability (and when used on emergency and standby systems may increase safety), detractors say there are no real-world incidents that support the need for it to become a national requirement.

“The proposal is like reducing the speed on interstates to 15 mph,” says Frederic Hartwell, Code consultant and electrician, Hartwell Electrical Services, Inc., Amherst, Mass. “I'm not going to argue that it won't save a few lives if you reduce the speed limit to 15 mph on the interstate, but there would be consequences — and they're unacceptable.”

The ship in a bottle

There are several differing opinions as to how selective coordination for emergency and legally required standby systems found its way into the NEC in 2005. According to Code-Making Panel (CMP) 13, the committee responsible for Articles 700, 701, and 702, Proposal 13-135, which required “All overcurrent devices in emergency systems shall be selectively coordinated… ,” was accepted into the NEC with the goal of increasing reliability and safety. However, some opponents accuse the proposal of being solely in the interests of fuse manufacturers attempting to shift the market share.

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