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March-April 2010
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TABLE OF CONTENTS

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Features

Safely Harnessing the Sun’s Energy

by Michael Johnston

Across the country and around the world, harnessing energy from the sun is becoming increasingly achievable for homeowners, businesses, and utilities alike. With an increased interest in solar photovoltaics (PV), comes a plethora of opportunities, as well as some challenges for the electrical industry. Amidst all the excitement and advantages of getting connected to alternative energy sources, the same safety hazards to persons and property should be realized by electrical industry partners, and more importantly, by consumers. Read more


Perspectives on PV

The Microinverter and the AC PV Module

by John Wiles

No discussion of PV systems would be complete without a look at the newest inverter technologies that the installer and inspector will face. These new technologies include the microinverter and the AC PV module. Read more

Are We Really Ungrounded?

by Keith Lofland

If you were to open an unopened jar, does that jar still qualify as "unopened”? No one would argue the fact that the moment I lock an unlocked door, that door is no longer "unlocked.” I must confess that this author has yet to come across an uneaten piece of cake and left that cake "uneaten.” So why do we consider an ungrounded system "ungrounded” when we are required to establish and connect a grounding electrode system to that ungrounded system? Read more


When is a sign not just a sign?

by Rick Hollander

Today’s demand for attention has brought on the need for signs to be more than just a display. Theses signs are designed for the potential customer to notice them and come in to check out the establishment. The sign might be portraying a message. Or it could be a show in itself. Let me take you on a quick step-by-step tour to inspecting signs. Read more

The Evolution of Communications Circuits & the NEC

by Ron Janikowski

In the beginning Samuel Morse, in 1844, started the digital data communications industry with a 37-mile stretch of wire sending what became known as Morse code from Washington, D.C. to Baltimore. Remember the day? Read more


The Importance of the AHJ in Fire Pump Installations

by Richard (Dick) Schneider

The services of the inspection community are of utmost importance to maximize safety and reliability. This is especially true when the inspector serves as the AHJ for the installation. This article addresses two such instances pertaining to fire pumps, one is covered by the National Electrical Code (NEC) in 695.4 and the other in the National Fire Protection Association (NFPA) Standard for the Installation of Stationary Pumps for Fire Protection, NFPA 20. Read more

Stray Voltage — Catching What We Cannot See

by Jonathan Cadd

"Where the cow won’t give milk anymore” is a standard lyric in old classic country songs; perhaps you’ve wondered why. Well, back in the early days many strange and downright bizarre occurrences happened on the farm, most of which were thought to be the product of superstition, bad living or old wives’ tales; but that was before modern measuring equipment, grounding methodologies, equipotential planes, voltage gradient ramps (transition areas) and ensuring a low-impedance path to ground. Let’s compare what many have believed and what modern principles of electricity have proven to be the real culprit and, in many cases, the reason for these strange and often devastating occurrences that plagued many livestock farms in the U.S. and throughout the world. Read more



Departments

Editorial

Unmasking Hidden Dangers

by Kathryn Ingley

Despite more than two hundred years of avid domestication, electricity is neither docile nor submissive. Underneath, it remains wild, unyielding and deadly; daring any to unmask its hidden dangers. Unperceived and unsuspected, these dangers lie in concealment, without motion, for long periods of time before savagely attacking. Read more

Canadian Code

GFCIs – Where are they?

by Leslie Stoch

The 2009 Canadian Electrical Code is peppered with references to, and requirements for ground-fault circuit interrupters (GFCIs). For very good reasons, GFCIs have become prevalent throughout many sections of the electrical code. And usually without our knowledge, they have no doubt prevented many injuries and saved many lives. This article provides a summary of these CEC rules. Read more

Canadian Perspectives

Standby and emergency power supply. Is there a difference?

by Ark Tsisserev

Let say, a designer decides to install a backup power supply for the IT network in the office, or to provide an alternate source of power to the sump pump in a building. Or a decision is made to have a standby power source for lighting in all classrooms of a high school. Or what if a backup power supply is provided for all building exhaust, makeup fans and fans used for smoke control and smoke venting? And what about the same approach to the elevators or fire pumps? And how about the standby power intended for emergency lighting in exits or in corridors used by the public? And to make it fun, let’s even consider a backup power supply to a typical house. What kind of power supply sources should be used to provide a standby power supply to all these loads? Read more

UL Question Corner

Circuit breakers and old panelboard; will anything work?

by Underwriters Laboratories

I have an old panelboard made by a company that was sold and no longer produces panelboards or circuit breakers under their old name. How do I find circuit breakers listed for use in the panel when the manufacturer is no longer in business, can I use any circuit breaker that fits? Read more

UL Question Corner

When is the UL White Book published every year?

by Underwriters Laboratories

Historically, the UL White Book has been published in late June every year. However, effective with the 2010 edition, the UL White Book will now be available in early April. So look for the 2010 UL White Book from the UL representative at your local IAEI meeting or download a copy online at www.ul.com/codeauthorities. Read more

UL Question Corner

UL and Installations of Alternative Power Equipment?

by Underwriters Laboratories

Does UL have any additional information available to AHJs or installers regarding installations of photovoltaic systems, wind turbines and other alternative power source equipment? Read more


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