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November-December 2010
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Marking of Available Short-Circuit Current

by Daniel R. Neeser

In the 2011 National Electrical Code® (NEC) Report on Proposals (ROP) process, two proposals were submitted and accepted that required the marking of the amount of available fault current on service equipment or enclosures that contain service or feeder overcurrent protective devices. The intent of the proposals was to provide a marking of the maximum available fault current to assist owners, designers, engineers, installers, inspectors and others concerned with the proper selection and application of equipment in accordance with the requirements of NEC 110.9 and 110.10. Section 110.9 covers the requirements for interrupting rating (IR) of equipment, such as overcurrent protective devices. Read more

Perspectives on PV

Utility Interconnections and Code Requirements

by John Wiles

Inspectors and installers continue to puzzle over the requirements in Section 690.64 of the National Electrical Code (NEC) that apply to the connection of utility-interactive inverters to the premises wiring and finally to the utility. This article, using the simplified block diagram, will attempt to clarify some of those requirements. Please refer to previous Perspectives on PV articles over the last two years for more detailed information. Read more

Luminaires, Lighting, and LEDs

by Jonathan Cadd

Since the dawn of mankind when fire was discovered and the light derived from it started man’s quest to conquer the night and eliminate darkness, we have searched for the perfect light source: a source that would give us an infinite amount of light for all of our daily and nightly activities, yet cost but a fraction to operate; a source that would use little energy yet produce reliable, brilliant, usable light on demand time after time; a source that would be attractive and functional for several years. The high-tech lighting that exists today is nothing short of a miracle and magnificent to behold, as it mesmerizes both mind and eye, while at the same time providing for our daily needs. Read more

Can You Benefit from Tax Swaps?

by Jesse Abercrombie

In all of my years working with electrical professionals I’ve yet to meet someone who likes paying taxes. We all know that it’s a part of life but it seems that the more successful we become and the older we get, it becomes more of an issue. Many people I work with benefit from investing in tax-free bonds and the tax benefits that are associated with them. But what if you own equities? Like most investors, you have probably been cheered by the market rally we’ve seen since March 2009. Yet, despite this dramatic reversal of fortune, you still may own investments that have lost value since you purchased them. If that’s the case, you may want to put these "losers” to work before 2010 ends. How? By using them in "tax swaps.” Read more

Ground-Fault Protection Systems and Electrical Inspections

by Howard Herndon

Ground-fault protection of electrical equipment is required by the National Electrical Code (NEC) in order to minimize the damage to the equipment in the case of a ground fault. Ground-fault protection of equipment is "a system intended to provide protection of equipment from damaging line-to-ground fault currents by operating to cause a disconnecting means to open all ungrounded conductors of the faulted circuit. Read more

Backfeeding Ground-Fault Circuit Breakers

by Ed Larsen, Bob LaRocca, and Jeff Hidaka

The wording of the exception may introduce confusion as it states that the ground-fault protection device "shall be identified…for backfeeding,” which implies a specific marking on a circuit breaker equipped with GFPE. In actuality it is the absence of "line” and "load” markings on a circuit breaker that indicates that it is suitable for backfeeding. Read more

Electrical Code for the Combination Inspector, Part II

by Randy Hunter

Article 90 is rarely given consideration when someone references the National Electrical Code (NEC). However, this is where we find the purpose statement for this code, and it shapes the entire application and enforcement of the requirements in the NEC. According to Section 90.1, the purpose of the NEC is for "…practical safeguarding of persons and property from hazards arising from the use of electricity.” Section 90.1 makes it clear that the requirements in the NEC will result in an essentially safe electrical system, but that it may not be efficient, convenient or even adequate for good service. The code explicitly states that the NEC is not a design manual and is not intended for untrained persons. By implication, this means that the NEC is intended primarily for electricians, electrical engineers and electrical inspectors, since these are the professions that are trained to understand and apply the requirements within this code. Read more

Learning Never Stops

by Rick Maddox

It is hard to believe, but 2010 is almost over and with it, my term as IAEI International President is drawing to a close. As I prepare to pass the gavel to our First Vice President Chuck Mello, I would like to express my gratitude to all of the membership for the honor of serving the association as the 82nd IAEI International President. The year 2010 has been a transitional year with the retirement of Mr. James Carpenter as IAEI CEO/Executive Director on January 1st of this year. I would like to wish Jim and Mary Ann all the best, and I hope Jim’s impact on the depletion to the North Carolina fish population is minimal. Read more

Testing 600-V Cable

by Jeff Jowett

There are a variety of technologies and methods used to test the insulation of wire and cable, including high-potting, very low frequency (VLF), power factor, partial discharge, time-domain reflectometry (TDR), and "thumping.” Like a visit to the doctor’s office, each test examines the test item in a different way and looks for a different response from the insulating material. Which test(s) and how many to employ is a judicious decision to be made by a skilled technician. This article will focus only on the most basic and fundamental test, insulation resistance. There is still debate among industry professionals regarding the value of testing, when and how often, what techniques and voltages to employ, and so on. Differing opinions and advice are available in the literature. This article is based on the acceptance of testing as being of fundamental value. Read more

Letters to the Editor | Comment on Improving System Reliability

by Ravi Ganatra

When it comes to terminating electrical conductors, Ms. Hunter’s field study, "The Difference between Success and Failure: How a Torque Wrench Improves System Reliability” published in July/August 2010 issue of IAEI News, demonstrates the importance of doing it right the first time.The expected reliability of electrical connections can be described by a curve shown in figure 1. Read more

Book Review: A Pictorial History of Radio and Electricity

by David Shapiro

Once in a long while, I see a book that will appeal to many of us, even though it won’t help us wire or inspect. The latest is John D. Jenkins’s Where Discovery Sparks Imagination, A pictorial history of radio and electricity. It offers both stunning photos and intriguing tidbits of fact. Read more

LED Adaptive Lighting and the Smart Grid

by Jim Frazer

The term intelligent transportation system (ITS) describes the process of adding control, monitoring and communications technology to transportation infrastructure and vehicles to improve safety, reduce energy consumption and to reduce vehicle wear and transportation time. Development and application of ITS technology is also driven by the need for homeland security. Many of the proposed ITS systems also involve surveillance of the roadways, which is a priority of homeland security. Additionally, through coordination with the US Department of Energy, many ITS applications are also supported, enhanced and on occasion driven by the needs of the Smart Grid electrical distribution technologies. Read more



Despise Not Small Things

by Kathryn Ingley

It was a small task, really; I don’t know why I kept putting it off, particularly in light of the touted return on the investment. Maybe I simply didn’t believe replacing the incandescent light bulbs in my house with CFLs could really lower my monthly light bill by half. Or even by a third! My procrastination is not unlike that of so many—if a task is not urgently pushing itself to the top of our agenda, it doesn’t get done. Read more

Canadian Code

Hazardous Locations — Section 18

by Leslie Stoch

Section 18 of the Canadian Electrical Code contains the rules for electrical equipment and wiring in locations where flammable vapours, gases or mists could create a fire or explosion, dusts capable of creating a fire or explosion or ignitable fibres are present. This article reviews a number of requirements applicable to Class I explosive gas atmospheres when classified in accordance with either the European Zone or North American Division methods of classification. Read more

Canadian Perspectives

Essential Electrical — Who is to say?

by Ark Tsisserev

Some building developers and owners like to consider the building IT infrastructure, building heating and air-conditioning systems, elevators, sump pumps and water treatment equipment as the "essential electrical system.” As such, these developers might demand from electrical designers additional provisions for reliability in performance of the loads comprising these "essential electrical systems.” There is no problem for designers and installers in this regard, as a redundancy could be easily provided in the design and installation of the electrical infrastructure. Read more

Safety in Our States

Electrical Safety in Existing Homes

by Thomas A. Domitrovich

Many owners of older homes have experienced "small” renovation projects that have morphed into much larger projects due to identification of safety related issues. Existing structures can present challenges to homeowners, as they make changes over time. Unfortunately, as both homeowners and contractors delve into a project, they find a variety of latent issues — from mold to hidden safety issues. As an expert, it is important to be able to help homeowners navigate and resolve the electrical safety issues they uncover. From the simple to the complex, it is critical to be a part of the solution as a resource, and to provide guidance on how to best address the electrical issues at hand. As we apply new code changes to existing homes, your skills and knowledge are ever so important to safety. Read more

UL Question Corner

Does UL List LED Tube Lamps and LED Edison Screw-Type Base Lamps?

by Underwriters Laboratories

LED tube lamps intended to replace fluorescent tubes are not eligible for Listing as a stand-alone lamp at this time. Currently the industry has two types of products on the market that are certified by UL: lamps that are intended to operate directly from line voltage (120 V) or lamps in combination with a remote, line voltage driven power supply. The output of the power supply goes onto the lamp. Both products can be used in the construction of new luminaires but of greater interest is the ability to use the lamps for conversion of existing luminaires. Read more

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