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September-October 2005
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September-October 2005 CoverSeptember-October 2005

TABLE OF CONTENTS

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Features

Guidelines to Evaluating Unlisted Products

by Len Frier

The American Council for Electrical Safety (ACES) is a collaboration that was formed by a variety of regulators responsible for ensuring the safety of electrical products sold in the United States. The council is sponsored by the American Council of Independent Laboratories (ACIL). Members of ACES include chief electrical inspectors, accredited laboratories, government agencies involved with regulation of electrical products, devices or installations, and representatives from organizations involved in regulation, such as IAEI. Read more

Perspectives on PV

* Making the Utility Connection

by John Wiles

More than 90 percent of the new PV systems being installed throughout the United States are connected to the local utility with utility-interactive inverters (figure 1). These inverters range in size from about 250 watts (rated ac output) to about 250 kW. Multiple inverters may be used at a single location to provide even higher outputs. The connection requirements to the utility are established in various sections of the Code. Unfortunately, in many cases, these requirements are not fully understood or complied with. This article will concentrate on the requirements of the 2005 National Electrical Code Section 690.64, Point of Connection. Read more

How Does EMC Matter to Global OEM Drives User-Specifiers?

by Mark Kenyon

Electromagnetic compatibility (EMC) is the ability of electrical/electronic equipment to operate in its installation environment while neither causing nor experiencing electromagnetic interference (EMI). EMI is any interference with normal equipment operation caused by abnormal energy entering the equipment either by conduction though wiring connections or by radiated wave reception. Radiated EMI is also called radio frequency interference (RFI). Conducted EMI is also called high-frequency line noise. Read more

Inspecting Elevator Power Wiring

by Rob Forister

Every year they are involved in accidents that kill thirty people and seriously injure seventeen thousand.1 Before you let that statistic scare you into using another route, remember that you are fifty times more likely to get hurt taking the stairs. Also, half of these deaths involve people who are working on elevators.2 Falls or being caught by the moving parts of elevators causes most of these deaths. Article 620 of the National Electrical Code has evolved through the years in an effort to prevent these injuries. Read more

Hydrogen Super Highway

by Edison Park

Imagine traveling from New York to Los Angeles by car in 10.5 hours, while the rail system you are running on is producing enough extra hydrogen to power 70 percent or more of the nation’s entire energy demand at no extra charge? Sounds impossible? Read more

The NEMA Field Representatives Program: Helping Inspectors Meet Their Goals

by NEMA

The National Electrical Manufacturers Association Field Representatives Program promotes the use and adoption of the National Electrical Code and monitors regional developments of importance to the electrical manufacturing industry. Electrical inspectors can rely on the field representatives’ expertise to interpret how the Code applies to specific installations and to provide a direct link to manufacturers, which is critical to getting quick resolution on installation-related issues. Philip Cox, retired IAEI chief executive officer and executive director, as well as a former NEMA field representative, said one of the best attributes of the field representative is the ability to resolve problems between manufacturers and electrical inspectors. Read more

Selective Coordination of Elevator Circuits

by Todd Lottmann

During the past revision cycle for the 2005 NEC, a new definition was created in Article 100 for selective coordination. The need for this definition can be taken from its creation and shows the expansion of selective coordination requirements throughout the NEC. One of the basic requirements for the creation of a definition in Article 100 is the use of the term in two or more sections of the Code. The 2005 NEC now has multiple sections containing requirements for selective coordination of overcurrent protective devices and most are contained in sections pertaining to protection requirements for critical circuits involving life safety. Compliance with these selective coordination requirements is achieved through the selection of overcurrent protective devices with appropriate operating characteristics. The choice of overcurrent protective devices with the proper operating characteristics is not difficult. Read more


Trusts Can Help You Achieve Your Estate Planning Goals

by Jesse Abercrombie

I’ve been interviewing electrical contractors and others in the construction business lately about their perceptions of investing as it relates to working with people like myself versus doing it on their on. I always tell them how important it is to focus on their contracting business. I tell them this because there is a lot more to creating and preserving wealth than watching MSNBC while competing for bids with competitors. The wealth you’ve built really doesn’t mean much if Uncle Sam sticks his hand in at your passing. Estate planning is extremely important for the highly successful electrical contractor who owns several pieces of real estate, retirement plans and other businesses. Read more

Concrete-Encased Electrodes Required

by Michael Johnston

Part III of Article 250 provides the important concept of a grounding electrode system, where all grounding electrodes are required to be bonded together and function as a system as indicated in Section 250.50. Rather than reliance on a single grounding electrode to perform its function over the life of the electrical installation, the NEC requires the formation of a system of electrodes "that are present at each building or structure served.” There is no doubt that building a system of electrodes adds a level of reliability and helps ensure system performance over a long period of time, usually the duration of the life of a building or structure. It is important to understand that this requirement applies generally to all buildings or structures and is not limited in application to just commercial or industrial installations. Residential construction is included in these requirements. Read more

Engineering Series Rating: Is It Practical?

by NEMA

The 2005 National Electrical Code introduces a change regarding series ratings for circuit breakers that deserves careful review before applying an engineered series rating. The additional paragraph 240.86 (A) reads... Read more

Electrical Safety Precautions During Hurricanes

by ESFI

The Electrical Safety Foundation International (ESFI) warns consumers to beware of the dangers hurricanes cause when water comes in contact with electricity. Read more

Departments

Editorial

Don’t Let the Smoke Get in Their Eyes!

by James W. Carpenter

We live in changing times. It seems as soon as we get comfortable, or at least used to a situation, things change. The price of gas goes up again. Property evaluations and, therefore, taxes increase. Somebody commits suicide by blowing himself up to kill and maim others. These are the types of things that are making the news today. But many other things are happening that kind of fall under the radar. Things that may not affect us or our way of life right now, but may have far-reaching consequences as time goes on. Not so recognizable at the present time, these are the things that we must remain on the alert for. Read more

Canadian Code

Single-Conductor Issues

by Leslie Stoch

In this article, let us review issues concerning induced current flow in the metallic coverings of single-conductor cables. Single-conductor cables have some advantages over multi-conductor cables, especially in larger sizes. Tables 1 and 3 of the Canadian Electrical Code allow us to use smaller wire sizes for single-conductor cables than Tables 2 and 4 for multi-conductor cables. Naturally, the smaller cables are always easier to handle and install than the larger, heavier ones. Read more

Canadian Perspectives

Approved Electrical Equipment Facts and Confusion

by Ark Tsisserev

How often in Canada perplexed distributors or wholesalers of electrical equipment provided with various trademarks or other symbols of identification hear from a visiting inspector: "This equipment is not approved. It must not be offered for sale.” Electrical contractors can also share some of their confusion, when an inspector rejects a piece of electrical equipment for installation as being "unapproved,” although the equipment bears a familiar certification monogram. So, where is the problem, and why do "innocent” wholesalers or contractors encounter such adamant actions from the Canadian electrical inspectors? Read more

Other Code

Basic Electricity, Part 8

by David Young

Electrical resistance is not the only property of materials that resists the flow of current. Let us consider an experiment. Let’s purchase a 12,000-foot spool of insulated 20 AWG copper wire commonly used as communications wire and pull the wire off the spool and lay it out on the ground. If we take the two ends and connect them to a male electrical plug and plug it into a 120 V AC source, we would expect the current magnitude that would flow in the wire to be equal to the source voltage divided by the resistance of the wire. Read more

UL Question Corner

Is it permitted to replace a sign face on a listed sign?

by Underwriters Laboratories

This question was addressed in the March/April UL Question Corner column and since the publication, UL received a number of follow-up questions regarding this issue. It should be noted that UL 48, the Standard for Electric Signs anticipates that sign faces may likely be changed from time to time due to commercial changes in product and property ownership as well as damage that may occur to sign faces. Read more


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