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November-December 2012
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TABLE OF CONTENTS

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Features

On the performance of arc flash analysis in DC power systems

by Michael Furtak

Direct current (DC) arcing fault incident energy calculations are presented to assess the level of risk involved when working around high current DC apparatus. The proposed procedure allows evaluation of incident energy and arc flash boundaries, while taking into account as many circuit parameters as possible. These parameters include fixed or variable gap length, system voltage, available fault current, equipment configuration, circuit time constant and evaluated threshold energy for a second degree burn. Read more

Perspectives on PV

PV Systems in Unusual Locations, To Inspect or Not?

by John Wiles

In the normal workday, inspectors may drive pass numerous PV systems that are not located on a dwelling or a commercial building and are in somewhat obscure, out-of-the-way locations. When these systems are noticed, the question arises, Should they be permitted and inspected? Here are some examples of such systems. Read more

LED Lighting for Hazardous Locations

by Steve Henry

Light-emitting diodes are not a particularly new technology. Affordable LEDs have been available since the late 1960s. From then until now, the technology has steadily progressed in terms of cost-effectiveness, color options, light output, and efficiency. Thanks to ongoing advancements in semiconductors, optics, and materials, LED applications have grown exponentially.” Read more

Introduction to PLCs

by Steve Vidal

The programmable logic controller (PLC) is a microprocessor-based system that accepts input data from switches and sensors, processes that data by making decisions in accordance with a stored program, and then generates output signals to devices that perform a particular function based on the application. Read more

Diversify Your Investment Risk

by Jesse Abercrombie

All investments carry risk. But, as an investor, one of the biggest risks you face is that of not achieving your long-term goals, such as enjoying a comfortable retirement and remaining financially independent throughout your life. To help reach your objectives, you need to own a variety of investment vehicles — and each carries its own type of risk. Read more

5 Methods of Protection

by IAEI

All three elements of the fire triangle — oxygen, ignition source, and fuel — must be present simultaneously and in specific quantities for a fire or explosion to occur. Often, in hazardous (classified) locations, the electrical system will be the ignition source of the triangle. This article looks at five methods of protection to prevent electrical systems from becoming ignition sources in these locations. Read more

Appreciating Hazardous Areas

by Steve Foran

It was the turn of the century and after thirteen years working on the utility side of the transformer I took on the role of managing a Hazardous Area Electrical Training Center. Ironically, at the time I was completely unaware of hazardous areas. Hey, everyone has to learn about something for the first time. Read more


Article 230, Services

by Randy Hunter

Article 230 is in some ways the genesis of the electrical system, meaning that it is very often the starting point of the electrical installation for a facility. Therefore, this is where I would usually commence my inspection process. As a rule of thumb, if the service is installed in a good workmanlike manner, the rest of the installation would also look good. However, if the service is a mess, you can generally assume that you are in for a long inspection and several items to note on your inspection record. Read more

Grain Elevator Safety

by Thomas A. Domitrovich

What’s tall, holds some dusty stuff, and at times can go boom? You guessed it, grain elevators. This just may be a topic you don’t hear discussed very often, yet there are statistics associated with these structures that may surprise you. Headlines such as "Three More Victims Found after Explosion at Kansas Grain Facility . . .” or "2 Hurt in Grain Elevator Explosion in Tracy, Minn. . .” are very concerning and found all too often. A simple Google search for "grain elevator explosion” brings to light the urgency of safety in these types of facilities. Grain elevators have been around for quite some time and will be around for years to come as they are critical not only to many farmers across this country but also to this country’s economy. Read more



Departments

Editorial

Relevance

by David Clements

Due to new technology, social networking and competition, individuals have many options as to where and from whom they can obtain information. Consequently, associations, the traditional suppliers of industry information, are facing intense pressures. Gone are the days when members would automatically renew their memberships. IAEI is no different and we face many of the same challenges. Read more

Canadian Code

Canadian Electrical Code Appendix B

by Leslie Stoch

Many of the Canadian Electrical Code rules display a note, "See Appendix B.” Appendix B provides important information on interpreting and applying the rules. To be sure you’re on the right track it’s always a good idea to find out what Appendix B has to say. This article reviews a sample of excerpts from this valuable information source. Read more

Canadian Perspectives

Selection of Conductors — do we have a problem with this?

by Ark Tsisserev

Apparently, we do. However, there is no reason to generalize this problem. Although there might be problems (or rather challenges) for the code users in understanding of some requirements related to the selection of conductors, I’ll concentrate on two specific issues that have apparently become a source of confusion: 1. Introduction of Rule 4-006 into the CE Code; and 2. Recent UL/ULC Public Notice release 12PN-51. Read more

Safety in Our States

The Slash-Rated Breaker and Shared Neutral Applications

by Thomas A. Domitrovich

Think back one or maybe more years ago when you had to assemble that latest purchase in front of the Christmas tree; picture the moment, if ever, you decided to open the assembly instructions and read them. It could have been before you got started — as you were drinking your coffee looking at the box and all of the parts. Or perhaps it was half way through when you couldn’t figure out how two parts went together. If you’re anything like me, it was when you were all done and you had a handful of parts left over. When it comes to electrical products, no matter how simple or how many times you’ve installed them, reading the labels on the products and the instructions can go a long way for electrical safety. Read more

UL Question Corner

UL Certifies First Stand-Alone Replacement LED Tube

by Underwriters Laboratories

Yes, recently UL has certified (Listed) the first stand-alone LED tube for direct replacement of a fluorescent tube in a fluorescent luminaire. The replacement tubes operate in the existing ballast circuit present in the fluorescent luminaire. They have been evaluated to operate in the ballast circuit so that the LED tube does not adversely affect the ballast operation in the luminaire. Read more

Focus on the Code

Are Type AC and Type MC cables considered pre-wired raceways?

by Joseph Wages, Jr.

Is the definition of a raceway applicable to Type AC cable and Type MC cable since these wiring methods are factory assembled with insulated conductors? Are Type AC cables and Type MC cables considered pre-wired raceways? Read more

Focus on the Code

Are there any practical guidelines available to installers and the enforement community with regards to continuous loads?

by Keith Lofland

As stated in the question, NEC Article 100 defines a continuous load as "a load where the maximum current is expected to continue for 3 hours or more.” In some cases, the NEC tells us when certain loads are continuous. For example, 422.13 demands that a water heater with "a capacity of 450 L (120 gal) or less be considered continuous loads for purposes of sizing branch circuits.” Most commercial lighting and electric signs [600.5(B)] are considered continuous loads. Unfortunately, the Code does not always spell out clearly when to consider a load as a continuous load for calculation purposes. Read more



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