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May-June 2013
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TABLE OF CONTENTS

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Features

* Residential Service Calculations in the National Electrical Code

by Christel Hunter

Load calculations in the National Electrical Code have evolved over many decades. It was in the 1933 NEC that load calculation requirements began to resemble a format that the modern code user would find familiar. Since then, many things have changed, but the primary requirement remains the same — service equipment and conductors must be sized to handle the expected load. Read more

Perspectives on PV

* Gray Areas in PV and the Code

by John Wiles

The National Electrical Code, even though it is now almost 900 pages long, cannot specifically define every particular piece of equipment and every installation requirement for that equipment. There are always going to be areas that are left to the interpretation of the local inspector (the AHJ). This article will cover four gray areas that I get calls on and, perhaps, generate some discussion that may lead to clarifications. Read more

* How close would you stand to a jet engine?

by Steve Foran

In the early 90s, utilities were in the midst of massive change as downsizing, right-sizing—or whatever you called it — swept the continent. Driven by technology, fewer people were needed to get the same work done and from this emerged an industry called Process Re-engineering. Read more

* Residential Load Calculations

by Steve Douglas

Residential load calculations first appeared in the Canadian Electrical Code Part I (CE Code) in the second edition dated 1930. In the 1930 edition, the load calculation rules were in Section 6 Conductors. The calculations were quite different from the present day calculations. For residential installations, the calculations were based on the number of branch circuits being installed instead of the dwelling floor area. In the fourth edition, dated 1939, a demand factor table for lighting load based on the floor area was added. Read more

Taking a Bite Out of Arc Flash

by Thomas A. Domitrovich

Arc flash has and continues to be an issue for our industry. All you need to do is speak with someone who has survived an arc flash event or look at the statistics to understand the magnitude of impact these events have on not only that person who may have survived but also on everyone else either directly or indirectly involved; at work and at home. This is a problem in our industry that happens all too often but I firmly believe that these events can and should be things of the past. We have the technology and work practice knowledge to take a bite out of the statistics of arc flash, and NEC 2014 is making great strides in the right direction. Read more

What’s in a Tunnel?

by Joseph Wages, Jr.

Remember your first tunnel? I do; but now, it not only involves me but also my wife and children. Driving through the tunnel has become an event my family and I look forward to when we travel to the state of Alabama. The tunnel I speak of runs beneath Mobile Bay. My first encounter came at age sixteen, while I was on vacation with the Rankin Family to the white beaches of Gulf Shores, Alabama. Even though I will never forget that vacation and the fun I had on the beach and while fishing in the gulf, the tunnel really got my attention. Read more

Should You Take a Pension Buyout?

by Jesse Abercrombie

Have you recently received a pension buyout offer? If so, you need to decide if you should take the buyout, which could provide you with a potentially large lump sum, or continue accepting your regular pension payments for the rest of your life. It’s a big decision. Read more


Rooftop Wiring Temperature — Field Installation Experiment

by Howard Herndon

The rooftop temperature adders in NEC 310.15(B)(3)(c) were first included in the 2008 NEC. The proposal to include this requirement was based on a study that showed increased temperatures in conduits on rooftops in direct sunlight. However, there remained unanswered questions for the Southern Nevada Chapter of IAEI; they live with extreme temperatures, and yet installers and inspectors have not seen evidence of failure related to rooftop installations. Read more

Criteria for Selection of a Rating of Service, Feeder or Circuit — Is there any confusion?

by Ark Tsisserev

Apparently, there is some confusion on this subject. Let’s tackle it step-by-step. Consumer’s service, a feeder and a branch circuit are defined by the Canadian Electrical Code as follows: "Service, consumer’s — all that portion of the consumer’s installation from the service box or its equivalent up to and including the point at which the supply authority makes connection..." Read more


Article 250 — Grounding and Bonding

by Randy Hunter

Article 250 is the largest article in the National Electrical Code. It is often the most dreaded by those new to the code, and sometimes even by those who have dealt with the code for years. Some of the terminology is confusing and conceptually difficult to follow. In keeping with the Combination Inspector emphasis of this series of articles, we will cover those items which I have previously taught to inspectors who weren’t electrical by trade. In doing so, we will not cover every section of Article 250, but concentrate on those that are used most commonly by multi-trade inspectors. Read more

What is Grounding?

by Leslie Stoch

The Canadian Electrical Code’s long-winded definition of grounding is shown as: "a permanent and conductive path to the earth with sufficient ampacity to carry any fault current liable to be imposed on it, and of sufficiently low impedance to limit the voltage rise above ground and to facilitate the operation of the protective devices in the circuit.” This article discusses a number of permissible grounding requirements and methods covered by the Canadian Electrical Code. Read more



Departments

Editorial

EVERY little thing matters in branding

by David Clements

In its simplest terms, branding is who we are, how others feel about us, and how industry and the public view us as an organization. Every time a prospective member, a potential customer or the general public contacts us, by whatever means, they formulate an opinion of us which creates our brand. Read more

UL Question Corner

Are All Grounding Lugs Listed for PV?

by Underwriters Laboratories

Can I use any UL Listed grounding lug evaluated to UL 467 for grounding a photovoltaic (PV) panel or supporting rack system? What devices are evaluated for grounding and bonding PV modules and mounting racks to comply with 2011 NEC Section 690.43(C), (D), and (E)? Read more

Focus on the Codes

What’s Happening to Table 310.15(B)(7)?

by John Stacey

In the 2011 NEC, does Table 310.15(B)(7) override any ampacity adjustment factors, such as temperature correction factors, or do any ampacity adjustment factors render Table 310.15(B)(7) noncompliant? Read more

Focus on the Codes

Are there any provisions in the NEC that address the de-energizing of rooftop photovoltaic (PV) wiring in an emergency situation for first responder emergency personnel?

by James Rogers

Let’s begin with de-energizing. It is well understood that when electrical circuits and equipment are de-energized, they are disconnected from a source of power utilizing a disconnecting means. Using this analogy, your question could be rephrased to inquire if there is a requirement for a disconnecting means for PV circuits; that direct answer is yes. Read more


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