NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, has championed the importance of an electrical preventative maintenance (EPM) program for years. Beginning in 1968 with requests to the National Electrical Code (NEC) committee for maintenance recommendations, 70B has more than 300 pages of valuable information on how to create and carry out an effective EPM program.


Two of the companion documents from the National Fire Protection Agency (NFPA) have formally recognized the importance of such programs with mention in the latest and forthcoming editions. The 2008 edition of the NEC was the first to stress the importance of maintenance, with the addition of Article 708 on Critical Operations Power Systems, stating: “708.6 (C) Maintenance. The authority having jurisdiction shall require a documented preventive maintenance program for critical operations power systems.


“FPN: For testing and maintenance procedures, see NFPA 70B-2002 Recommended Practice for Electrical Equipment Maintenance.”


The 2015 edition of NFPA 70E, Standard for Electrical Safety in the Workplace, adds a new Section 110.1(B)Maintenance, which states: “The electrical safety program shall include elements that consider condition of maintenance of electrical equipment and systems.”


The 13th revision to NFPA 70B is well into the fall 2015 revision cycle. 


The NFPA recently changed the standards’ development process, though it is still one of the most open to the public and peer-reviewed processes. All NFPA committees working on standards—including the NEC, 70E and 70B—use this procedure. It starts with the technical committees having a balanced representation of manufacturers, users, utilities, government, insurance, labor, inspectors and other members from other standards groups, such as the Institute of Electrical and Electronics Engineers, the National Educational Telecommunications Association and the National Electrical Manufacturers Association. No group may have more than a one-third total representation on the committee. The standards revision process goes through several stages, now called the public input (formerly called proposals), first draft (formerly report on proposals), second draft (formerly report on comments), and notice of intent to make a motion at the annual general association technical meeting, where it is balloted by membership at large if there are any comments in opposition to the proposed revisions.


The next revision should contain another set of significant changes in several areas, including battery maintenance, use of terms “labeled” and “listed” and how maintenance and repair can affect them, tightening connections, risk assessment, updating references. Perhaps most significantly it will have a number of new case studies demonstrating the value (including monetary impact) of failures without proper EPMs.


In the previous edition, new material addressed renewable-energy sources. Wind turbines and photovoltaics (PVs) are quite different technologies, but they share a common potential power quality problem. The varying wind does not make the turbine turn at a constant rate, such as a multiple of 60 hertz, and the resulting frequency is surely not synchronized to the grid frequency. The solution employed within this power source is to convert the alternating current (AC) power at varying frequencies to direct current (DC) power, then convert the DC back to a synchronized AC voltage. Such a power conversion is similar to what happens in adjustable speed drives. I have discussed the resulting current harmonic impact of such conversion on electrical systems in previous issues of ­ELECTRICAL CONTRACTOR. The same holds true here. In addition, some dynamics of the system can result in increased flicker phenomena.


PVs have a similar inverter, except it takes the DC power from the photocells and converts it to synchronized AC voltage (one fewer conversion step than with wind power). Again, inverter = current harmonics. Large PV applications also can have a new power quality problem, called “cloud transients.” As a cloud passes over a large array, the output of the cells will drop and then come back while others drop, depending how the cloud’s path crosses over the cells. This can result in a modulation voltage, causing light flicker.


An effective EPM can reduce power quality-related problems. Power quality was considered such an important part of electrical equipment maintenance that Chapter 10 of 70B is dedicated to it, explaining causes, test methods and possible solutions to the major categories of power quality phenomena. Tightening connections on busbars and other parts of the electrical system can decrease impedance, which results in less severe voltage variations. Properly maintaining breakers and batteries will decrease the risk of catastrophic failures that result in long duration interruptions. Part of an effective EPM is doing baseline testing during systems commissioning, which is very important when doing periodic power quality monitoring during the life of the facility or system as it evolves.


So, if you or those who make the financial decisions at your customer’s facility don’t think that an effective EPM pays dividends many times over, go on to www.nfpa.org and preview NFPA 70B. Take a close look at the new case studies in the first draft that clearly spell out the financial impact of not doing it.