Talkin’ NEC 708

One out of every six dollars spent on power system equipment is spent on alternate power systems that back up primary systems.¹ To what degree does spending on alternate systems take from the investment needed to increase the security of the primary power system? Conversely, to what degree can investment in the alternate systems increase the security of the primary system? Power security i...

By Michael A. Anthony, P.E. Senior Electrical Engineer, University of Michigan, Ann Arbor May 1, 2007

One out of every six dollars spent on power system equipment is spent on alternate power systems that back up primary systems.

Power security is neither a purely technical problem nor one that can be solved by financing individual point solutions. But the dots are connecting:

In March, the Federal Energy Regulatory Commission (FERC) issued “Order No. 693, Mandatory Reliability Standards for the Bulk-Power System” and departed from the electric utility industry’s voluntary compliance with reliability standards developed by industry organizations such as the North American Electric Reliability Council. Recommendations about load-generation balance that were once gentlemen’s agreements among control areas within FERC’s jurisdiction are now binding.

The National Assn. of Regulatory Utility Commissioners, at its annual convention in December, gave permanent status to its Ad Hoc Committee on Critical Infrastructure. The committee gives state regulators a permanent forum to propose solutions to utility infrastructure concerns.

At the January technical committee meetings on the 2008 National Electric Code, a new technical panel (CMP-20) made final revisions to a new article titled, “Article 708: Critical Operations Power Systems,” (COPS) to take a place among the other alternate power systems covered in special systems Chapter 7.

COPS are not the Section 517.33 critical branch subsystems of healthcare facilities. COPS are distinct from the emergency, legally required and standby power systems covered in other Chapter 7 articles. With emphasis on the word “operations,” COPS ensure first responders and other emergency personnel have power at facilities where they assemble and communicate to carry out the rescue and recovery functions of government. This facility is identified as the designated critical operations area (DCOA). In many municipalities, the DCOA is at the police or fire department; in counties, it is the emergency operations center. At universities, it may be the plant operations facility.

Some salient characteristics of Article 708 are as follows:

Avoid physical damage to the DCOA with smart and circumspect siting

COPS equipment, such as transfer switches, transformers, panelboards and the like, shall be located in spaces with two-hour fire resistance rating

Make power and fuel sources secure, redundant, fire-protected and above the 100-year flood plane; where this is not possible, wiring methods shall be listed for use in wet locations

Start alternate power sources automatically, within the time required for the applications, and make them able to run a minimum of 72 hours

Protect telecommunications, signaling and controls; provide power to run HVAC apparatus, fire protection systems and everything else the emergency teams and their equipment require

Perform witness tests under full load

Where the COPS is supplied by a single generator, a means to connect a portable or vehicle-mounted generator shall be provided

Document just about everything.

The ongoing effort

Article 708 is part of a wider effort by the NFPA to focus its workgroups to meet the government’s need for improved power security standards.4In late 2005 the NFPA Standards Council put together a task group consisting of experienced code writers and early movers in the power security efforts following 9/11 and again after Hurricane Katrina. The article was originally labeled 585 and located in the Special Occupancy Chapter 5. Later, the NEC Technical Correlating Committee recommended that COPS appear in the Special System Chapter 7 under its present title. The requirements of Article 708 not only apply to systems within single function buildings but are also intended to be individually applied to critical operation facilities within a multifunction building. A list of possible COPS facilities, as well as more contextual information, is available at the following link: (starting at Page 347).

Here you will see more nuance on the issues of scope, power sources and connection, commissioning and functional performance testing. Annexes on SCADA, functional performance testing and reliability will be added to the back of the 2008 NEC as reference material. The requirements for absolute overcurrent selectivity will be carried into Article 708, thus keeping that debate alive. Adopting agencies will need to prepare a documented emergency operations plan if they do not have one already. NFPA Standard 730 – Guide for Premises Security and NFPA 1600-2004 Standard on Disaster/Emergency Management and Business Continuity Programs contains the framework for such plans. NFPA 1600 was specifically mentioned in the 9-11 Commission’s Final Report.

Perspective on power

Power reliability and security are often used interchangeably. The American Society of Civil Engineers (ASCE), for example, is preparing its own standard, Guide to Reliable Emergency Power for Lifelines.5Lifelines are systems and facilities that include communication, liquid fuel, natural gas, transportation, water, wastewater, etc. The effort by our colleagues in the civil engineering discipline to cooperate with FEMA in the development of ANSI-approved power security standards for the Department of Homeland Security is, perhaps, tacit recognition that electrical infrastructure is the “infrastructure of infrastructures.” Civil engineers contribute a great deal to power security by protecting from earthquakes and floods the transmission infrastructure upstream from the DCOA primary power service point. Thus, the ASCE Lifeline effort correlates more closely with the National Electric Safety Code (ANSI C2-2007). What goes on within the DCOA premises wiring system itself is the subject of Article 708 of the National Electric Code.

Because so much of the US critical power system is privately owned—as high as 85%, by some estimates—some requirements of Article 708 will have to meet local interpretation of the NEC scope statement in Section 90.2. Friends of the NEC know that this section of the code is where good people disagree. The electrical industry has a variety of ownership types (investor, rural cooperative, municipal, etc.) and what is, and what is not, covered in 90.2(B)(5) with the use of the term, “by other agreements” is not universally understood.

Differences in the interpretation of the scope of the NEC exposes the divide between the people who see the scope of the NEC as a “pipe and wire” kind of a thing, and those who see the NEC as an instrument to assert public policy.

My hope is that the Article 708 scope statement (See “Scope of 708,” p.42) does not delay the deployment of capital toward COPS while the industry waits for a more mature version of Article 708 in the 2011 NEC. A strong business case exists for stakeholders of all kinds to adopt Article 708 even if the scope statements can be construed to exempt them. The prospect for confusion among non-governmental authorities with statutory authority over the critical infrastructure was tracking in both the proposal and comment stage. The Edison Electric Institute (EEI), representing investor-owned utilities, followed the development of Article 708 closely. In its substantiation on rejecting Comment 20-3, submitted by the EEI, that the scope of Article 708 overreaches the intent of Section 90.2, the authors of Article 708 wrote:

“During construction of those [critical operations] facilities, the utility can request that Article [708] 585 be used, which would then fall under the facility engineering documentation establishing the necessity for such an occupancy.”

The deeper you drill down into the details of power security, the more you see that there is not yet a common vocabulary for the complex interplay of various infrastructures. Every well-meaning committee has its own idea of what is critical. The past two presidential administrations have contributed to the Babylonian confusion by defining “critical” differently.6,7

Every safety requirement, every policy initiative, comes with implications for the legal profession, for OSHA and for relationships with insurance companies. Organizations will need time to digest Article 708 and to resolve mass-tort and complex liability exposures. For some types of disasters, robust critical operations can reduce power loss duration times by making it possible for emergency management teams to work in an environment that will assist in preventive action and system restoration operations undertaken by the utility.

The authors of Article 708 intend for it to require a higher oversight than previously included in the code. It asks for more paperwork than we have ever seen in the NEC. It may take time for that higher oversight to be ready for this paperwork. What “facility engineering documentation” looks like, what makes it valid, where it is kept and who keeps it will have to play out in practice. (See “Sample Risk Assessment, p.46, for an example of one Michigan county’s risk assessment.) Risks must make sense for your locality.

Absent from the rankings in the sidebar is the risk of doing nothing. When it is written in NEC Articles 230, 695, 700, 701 and elsewhere throughout the NFPA Standards universe that…

“Assignment of degree of reliability of the recognized emergency supply system will depend on the careful evaluation of the variables at each particular installation”

…it means that owners, electrical inspectors, and those higher authorities may have to rely upon an engineer’s judgment of the reliability assessment.

Consulting engineers have the IEEE Standard 493 — Guide to Reliability in Commercial and Industrial Power Systems, the so-called “Gold Book,” on reliability from which they can model reliability along the power chain. You will have to become familiar with the notation and terms of art in reliability engineering. There are established companies already in the reliability and risk management software space but an electrical engineer will still have to prepare the circuit model and condition the data before it goes into any software. The output from this software will have to be interpreted in order to be meaningful to those higher government authorities. There is “fine print” that specifically recommends quality function deployment (QFD). QFD as a process to assist in conducting the risk assessment and getting the paperwork right.

When fully realized, Article 708 will reach deep into signaling design, commissioning, and maintenance practices.

Perhaps it is reading too much into Article 708 to imagine that a DCOA wiring requirement can hasten metamorphoses of the last mile of the U.S. power system into something more like a decentralized ecological system be made up of integrated resources with a self-teaching and self-healing characteristic of a neural net.7Perhaps DG and COPS inhabit different domains of policy. There are technical problems to overcome: load-generation mismatches, local instability and de-centralized response.8There are also market interface issues.

Many believe that the electricity markets need to be redesigned before wide scale implementation of DG.Others believe that power security should come first.Still others believe that market re-design and security are inextricably linked.9

But suppose the dots are connecting in a fashion that the most attractive alternative is for emergency response organizations to build these COPS to run interactively with the primary power delivery system. Over time, COPS upgrade programs could get us closer to the tipping point in which distributed generation, now relatively rare, becomes dramatically more common.

Article 708 specifically permits the dual use of the DCOA prime mover as a peak-sharing source as long as loads can be picked up selectively during emergency operations.Respected voices in the industry have pushed through changes elsewhere in the 2008 NEC that provide additional support for the dual use of prime movers.For example:

Section 700.9 will redefine the origin of the alternate power source so that separate vertical sections of a distribution switchboard will be permitted to provide physical separation of feeders to different alternate systems.This may reduce the cost of an alternate power installation where the designated critical operations area is an integral part of a multi-function building.

Section 702.5 will be modified to clarify loading parameters in alternate power installations with both manual and automatic transfer switch features.More flexibility will be permitted in how loads are connected and how loads are picked up by the generating facility in either mode.

These two changes help build the case for dual use of a prime mover—assuming that the cost of additional signaling complexity and commissioning is part of the capital recovery equation. Changes like these also show the 2008 NEC’s role in the national security and in the growth playbook in the business continuity industry.

Two other benchmarks for the metamorphosis of the national power grid come from private industry and the military:

The low voltage network transformers in Manhattan which, arguably, have supplied power to the most demanding service areas on earth, are being upgraded to permit power to flow in both directions. Consolidated Edison is building smaller substations with the ability to transfer primary power among themselves.10

On military bases, the U.S. Army Corp of Engineers is reconfiguring its emergency power system by connecting its existing emergency generators into a microgrid so that backup power can be moved around more easily between individual facilities.11

The cheaper we can make these DCOA’s, the more of them can be built, and all the better for national power security. Three code cycles from now we may look back to see that we have engineered ourselves back to the neighborhood power system of Edison’s original conception.

Moving forward

There are a lot of moving parts to Article 708. A good survey article appears in bibliographic reference.12In the transactions of the technical that have been published you can see that the submitters and the panel are more comfortable in the realm of wiring methods, listing of interconnection switchgear and single-phasing provisions than they are on facility engineering documentation and probabilistic risk analysis. Some believe that Article 708 is subjective and thereby difficult to enforce; others believe quite the opposite. Apparently, subjectivity is in the eye of the beholder. In any case, the NFPA process is up to the task of managing developments in either direction. Article 708 is a good example of the democratization of innovation; how the electrical industry has used the natural insight and inventiveness of the market to help itself.

It would have been nice to have been further along in the reconfiguration of our power system when fuel was cheap. People often talk about power security when they should really be talking price.Eventually security will rise to meet demand and the market will adjust. Private industry, with assets to protect from forced outages has, frankly, has been ahead of the safety community. For most of the general load on the US power system that is not of a critical nature, however, the bad news about power security may not yet be in the price.

The 2008 NEC, with Article 708 included, will be submitted for approval to the NFPA Standards Council in June 2007. Unless intervener floor actions preclude the use of Article 708 it will be available for public use before the end of 2007.First drafts of anything have errors and ambiguities in them — practically by definition — and so we will have to manage that risk, too.The NEC articles on fuel cells (692) and photovoltaic power (690) are relatively new and had their growing pains.One the oldest articles (250 on grounding) still churns in substance and presentation and subtlety.An imperfect Article 708 now is better than a perfect Article later.

What should consulting engineers be telling clients who, themselves, are under pressure to be on-time, on-budget and on-value? The value part of the equation will be difficult; security is always excessive until it is not enough. At the very least, we ought to be advising them to consider how local adoption of the 2008 NEC—with Article 708 included—may affect them. Start with the list of salient points in the beginning of this article. Follow up with inquiries into the status of mutual aid agreements that may exist with local emergency management agencies particularly on the matter of portable generators and that 72-hour requirement.

If the practical effect of the 2008 version of Article 708 does nothing more than embolden a few local emergency authorities to send up a request for funding to just study whether their critical power installation can meet COPPS performance requirements then the effort will have been worth while.Thought leadership, trust, will be necessary to move forward; so will statesmanship among related agencies.

Given price volatility in electrical equipment, there may be future costs associated with taking no action now.To paraphrase the proverbial two-handed economist: the market tends to favor first movers; sometimes not.Experienced electrical professionals know that the least expensive time to upgrade existing or build new critical operations power systems is the day before the next major outage.

Sample Risk Assessment for a Michigan County


Note that earthquakes in southeastern Michigan are ranked relatively low and that infrastructure hazards are relatively high. Used with the permission of the Emergency Management Division of Washtenaw County, Michigan.

Convective weather (severe winds, lightning, tornados, hailstorms)

Hazardous material incidents: transportation

Hazardous material incidents: fixed site

Severe winter weather hazards (ice/sleet storms and snow storms)

Infrastructure failures

Transportation accidents

Extreme temperatures

Flood hazards: riverine/urban flooding

Nuclear attack

Petroleum and natural gas pipeline accident

Fire hazards: wildfires

Oil and gas well accidents

Fire hazards: structural fires

Flood hazards: Dam failures

Public health emergencies

Sabotage and terrorism



Nuclear power plant accidents

Civil disturbances

Fire hazards: Scrap tire fires

Infestation (emerald ash borer, gypsy moth)


1. Power Play: A More Reliable US Electric System, Monograph by J. Apt, Lester Lave, M. Granger Morgan, National Academy of Sciences.

2. Federal Energy Regulatory Commission Proceedings, March 6 2007.

3. NARUC Press Release, Washington, D.C.—Dec. 11, 2006.

4. NFPA Standards Council Meeting, Final Minutes, Oct. 27, 2005, Item 05-10-28-d.

5. Guide to Improved Earthquake Performance of Electric Power Systems, 1999, American Society of Civil Engineers, Ansel J. Schiff (Editor), Technical Council on Lifeline Earthquake Engineering, ASCE Manuals and Reports on Engineering Practice No. 96.

6. The Clinton Administration’s Policy on Critical Infrastructure Protection: Presidential Decision Directive No. 63, White Paper, May 22, 1998.7. The National Strategy for the physical protection of Critical Infrastructures and Key Assets President Bush’s Definitions Feb. 2003.

8. “Nothing But Net: Article 230 and the Energy Web,” Michael A. Anthony, P.E., NEC Digest, June 2006.IEEE Standard 1547-2003 Standard for Interconnecting Distributed Resources with Electric Power Systems.9. “Grid Security,” Conference Proceedings of the IEEE Power Engineering Society, Transmission & Distribution Conference and Exposition, September 7-10, 2003.

10. Annual Financial Report of Fiscal Year 2006, Consolidated Edison, New York City.

11. “Control Dynamics of Adaptive and Scalable Power and Energy Systems for Military Micro Grids,” U.S. Army Corp of Engineers Engineering and Research Center, December 2006.

12. “When Failure Isn’t an Option,” Jim Lardear, NEC Digest, February 2007.

Author Michael Anthony .

Scope of Article 708

The scope of Article 708, Critical Operations Power Systems, to be included in the upcoming edition of the National Electrical Code, would be defined in the following way:

708.1 Scope. The provisions of this article apply to the installation, operation, monitoring, control, and maintenance of the portions of the premises wiring system intended to supply, distribute and control electricity to designated critical operations areas (DCOA) in the event of disruption to elements of the normal system.

Critical operations power systems are those systems so classed by municipal, state, federal, or other codes, by any governmental agency having jurisdiction, or by facility engineering documentation establishing the necessity for such a system. These systems include but are not limited to power systems, HVAC, fire alarm, security, communications and signaling for designated critical operations areas.

Note that with the exception of the terms “facility engineering documentation,” this scope statement bears similarity to the scope statements in existing NEC Articles 700 and 701.