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July-August 2012
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TABLE OF CONTENTS

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Features

Energy Alternatives and NEC Implications

by Michael Johnston

The world is changing rapidly and becoming more dependent than ever on expanded use of alternative energy systems and reducing and preserving grid-produced energy. The electrical infrastructure in the United States is one of the best in the world, but is aging and, to some degree, becoming more vulnerable to the effects of aging and loading. Society is typically not removing loads from the electrical grid, but is adding load. Read more

Perspectives on PV

The Conductors, Getting Solar Energy to the Inverter for 40–50 Years

by John Wiles

PV modules may be generating energy for 40–50 years after installation. While power production may not be what it was when the PV system was new, hazardous amounts of voltage and current will be still available from the PV array. The rooftop, outdoor environment is harsh. Unlike HVAC equipment, which requires periodic inspections and maintenance, PV modules and the rooftop wiring and equipment may not be examined for the life of the system. Read more

Transitioning Between Raceways

by Erik Senseney

For most electricians, the proper use of fittings is elementary. Fittings themselves are pretty straightforward in their use. Referencing Definitionsin theNational Electrical Code under the entry:Fittings, we are informed that a fitting is "an accessory such as a locknut, bushing, or other part of a wiring system that it is intended primarily to perform a mechanical rather than an electrical function.” From experience, we know that fittings are straps, hangers, couplings and connectors which connect (or couple) a raceway to itself, a box, device, enclosure, or similar electrical apparatus — pretty simple. Read more

Evaluation of Onset to Second-Degree Burn Energy in Arc-Flash Hazard Analysis

by Michael Furtak and Lew Silecky

Our interest in determining accurate onset to second-degree burn energy and its significance in computing the arc-flash boundary is focused on the prevention of injury to the skin of a human who might be exposed to an arc flash. During the last two decades different formulas have been proposed to calculate incident energy at an assumed working distance, and the arc-flash boundary in order to determine arc-rated personal protective equipment for qualified electrical workers. Read more

Article 220, Continuation

by Randy Hunter

Starting with Part III of Article 220, which is titled Feeder and Service Load Calculation, we will finally start with the actual math work. First, we will discuss demand factors as referenced in 220.42, and listed in Table 220.42. These demand factors take into consideration that in buildings we don’t normally have every electrical device operating at the same time. For instance, in a residence you will see in the table that the first 3000 VA is taken at 100%, then from there on we step down to a factor of 35% up to 120,000 VA, then down to 25% beyond that. If we refer to Table 220.12, we find that in dwelling units we use 3 VA per square foot. Read more

SCADA and Homeland Security

by Jonathan Cadd

Not so long ago when an industrial plant operator needed to redirect flows or even start and stop a procedure, it was often times a long and arduous process of turning valves, painstaking sequences, and long trips from area to area within a plant or facility with a handheld radio. While there are still facilities that might require this type of manual operation, the landscape has significantly changed, with the introduction of supervisory control and data acquisition (SCADA). Read more

Standard Motor Control Circuits

by Stephen J. Vidal

Single-phase and three-phase AC squirrel cage induction motors need some type of circuit to initiate a start or stop function. Usually single-phase motors and smaller horsepower three-phase motors can be started with full voltage across the line. However, larger horsepower three-phase motors require reduced voltage starting techniques. Read more


The Grateful Leader

by Steve Foran

Here is a simple idea to enhance your capacity for leadership using gratitude. Gratitude is often misinterpreted as a sign of weakness — especially in business. For instance, the majority of my clients at some point tell me that they are nervous about hiring me because they were not sure how their people would respond to the idea of gratitude, but it does not take long for them to realize that gratitude can seriously improve their ability to lead others and to achieve results. Read more

Departments

Editorial

FACE-TO-FACE TIME — Its value and where to find it

by David Clements

Never underestimate the value of networking face-to-face! Despite the various ways of communicating — phones, email, instant messaging, social media, faxing, snail mail, telegram, or carrier pigeons — the "time spent interacting in the presence of or in the same location as another or others” is still the most productive and valuable. In fact, it is becoming priceless — and rare. Read more

Canadian Code

Rule 4-004, Comparable But Different

by Leslie Stoch

You probably noticed a number of important changes from 2009 to the 2012 edition of the Canadian Electrical Code. Section 4 – Conductors has taken the lion’s share of the changes. Rule 4-004 has received a good deal of attention. This article discusses and compares some of the similarities and differences between the 2012 version of Rule 4-004 – Ampacity of Wires and Cables and its 2009 predecessor. Read more

Canadian Perspectives

Essential Electrical System — Who is to say?

by Ark Tsisserev

No, really — who is to say? Where is such entity defined or described? The answer could be found in two following documents: (1) In the CSA standard Z32, which is actually called Electrical safety and essential electrical systems in health care facilities; and (2) In Section 24 of the Canadian Electrical Code which covers installation of electrical equipment in patient care areas. Read more

Safety in Our States

Safety Something Earned

by Thomas A. Domitrovich

One could argue that due to the technologies on the market, arc flash and other electrical life-threatening events should be rare occasions. But electrical safety is more than just applying a product or sitting through a training class; it’s a regiment of training and procedures implemented in combination with technology that saves lives. There’s no silver bullet for safety. Just like respect, and I don’t mean the respect we should give electricity, safety is earned. Simply attending class and punching your ticket, so to speak, is not enough. Read more

UL Question Corner

Is the XO Jumper Sized Correctly?

by Underwriters Laboratories

Is the XO bonding jumper strap provided in certified (Listed) dry type core and coil transformers used in typical commercial installations adequately sized? Read more



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