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About RF Cafe
1996 - 2016
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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"The National Electric Code (NEC) has its own unique logic. Totally humorless, rigorously honest and forthright, Aristotelian rather than Platonic, it undergoes revision after revision, always looking to keep up with innovations. It is scrupulously aware of its mandate to promote safety and yet not be afraid to spin out into new regions of electronics knowledge." Those are the opening sentences of chapter 3 of a new book by Master Electrician David Herres, titled, "2011 NEC Chapter-by-Chapter." Call me a nerd for actually enjoying a book like this, and call me a highbrow for appreciating the profundity of such insightful prose. I make no apology. Would you normally expect to experience writing like that from an electrician? Not to denigrate electricians or other tradesmen (after all, I began my career as an electrician), but comparisons between Aristotelian and Platonic philosophical bents are the realm of literature students. To that end, I wrote to Mr. Herres to delicately probe his background beyond that of electrical work. In fact, he has a Bachelor's Degree in English literature - no surprise there.
Far from what you might expect of a book bearing this title, the text is very readable in its goal of explaining the overall strategy of chapter order and structure, while delving deep into the details as necessary to make notoriously difficult concepts understandable. Far from being a rote regurgitation of chapter and verse, David effectively combines his obvious mastery of the electrical code with his writing skill to guide the reader - typically someone in the process of studying for taking the Master's Electrician exam - through the complexity and succinctness of each item of code while offering advice on how to locate pertinent information needed to pass the test. Of course the advice applies not just for exam takers but also to field practitioners on a day-to-day basis. No, "2011 NEC Chapter By Chapter" is not a novel by any means, but it is about as close as you could hope find in a book whose mission is to explain such a massive bureaucratic publication conceived of and written by committees.
The book opens with a discussion about why and when licensing is required and what the path to a Master's Electrician license entails. "Many people assume that there is a nationwide licensing for electricians, but this is not the case. Each state, municipality, or other venue issues its own set of licenses. Requirements and enforcement vary widely." A thorough distaste for "trunk slammers" is apparent throughout the book. Mr. Herres then talks about what the NEC does and does not cover, and lays out the overall structure of the code with advice on how to quickly locate sought-after information. He believes becoming familiar with, even memorizing the contents of the index, is the key. After the introduction, a methodical progression is made through each of the nine chapters and the annexes.
Most likely, those who read this article will be electronics and electronics engineers and technicians that happen to see it posted on my RFCafe.com website. They might be tempted to ask why special consideration would be given for the topic of electrical code that concerns house wiring? Those who do, have never been properly introduced to the NEC and the great expanse of topics to which it pertains. Being an electrician often goes far beyond simply pulling Romex through wooden studs and installing receptacles, switches, and ceiling lights. The NEC provides guidance and ultimately, depending on your location, the force of law to nearly every kind of electrical installation, from very low to very high voltage. Even manufacturers of electrical equipment must comply as required to the NEC as well as to other authorities like the Underwriter's Laboratory. There is a good chance that products you have worked on in your engineering or technician career have been subject to one or more of the requirements in the National Electric Code - whether you knew it or not.
If you are a hobbyist such as an amateur radio operator, you may have unknowingly violated a portion of the NEC by improperly grounding and/or bonding your equipment, running outdoor overhead power lines too low to the ground or a rooftop, not deep enough underground, or maybe by attaching antenna guy lines or elements to structures reserved exclusively for a service entrance drop conduit. The FCC licensing exams for Hams provides recommendations for such topics, but they do not really have the force of law behind them; the FCC does not regulate power and ground connections related to radio gear, only the electromagnetic spectrum usage. Chapter 8, Communication Systems, covers transmitters and receivers, antennas, etc., mainly for commercial installations, but amateurs are not immune to its requirements. Failure to comply with regional codes could lead to prosecution and denial of insurance coverage if an incident occurs where an investigation reveals operator fault. Remember the old adage about ignorance of the law being no excuse.
Beyond relatively simple residential wiring, there is a plethora of commercial and industrial applications that require a very high familiarity with manipulations of mathematical formulas for calculating wire temperatures based on ambient conditions and insulation type, conductor fill percentages of conduits and enclosures, amperage overrating for circuit breakers and conductors, delta-wye, delta-delta, wye-wye and other transformer configurations, soil conductivity for grounding systems, multi-phase motors and equipment connections, inrush currents, electrical generation and distribution capacities, and a host of other scenarios. Intimate knowledge of circuit partitioning, cable and conduit spacing and attachment, types of circuit breakers and fuses required, co-location with other utilities and structures, protection from harm (both equipment and human), labeling, cooling, and of utmost importance grounding and bonding is essential. Wind generators and solar arrays are discussed. Even proper construction of field-assembled extension cords are governed by code. The list goes on and on. Passing the Master's Electrician exam requires no less expertise on the part of an electrician than does passing the Professional Engineer exam for an engineer. All of these topics are professionally addressed as the reader progresses through this very comprehensive book.
David makes no attempt to demonstrate actual calculations in his book, but if you are the type of person who is averse to a little basic math, chances are you will never obtain your Master's Electrician license. Nevertheless, "2011 NEC Chapter-by-Chapter" is still a valuable addition to the library of every practicing electrician. Even if someone else does the planning and calculations for you in a central office, it is still essential that you know all the rest of the material that applies to your job. Failure to comply can cost your company money and reputation, and could cost you your livelihood. Gross negligence can be and is often prosecuted in courts of law.
Grounding and bonding to eliminate unintentional voltage rises, with their attendant potential (pun intended) for electrocution, is highly stressed and enforced, and is crucial for reliable operation of modern equipment with integrated electronics. I can remember having to troubleshoot a problem that one "newfangled" electronic cash register was having in a hotel restaurant. Its woes were due to poor bonding; simply providing a ground connection for the power plug was not good enough. I answered many service calls from people whose equipment was damaged by lightning strikes - not necessarily direct strikes. Undoubtedly many situations could have been prevented by better grounding and bonding. Mr. Herres points point out the importance of adhering to conductor curve radii in order to avoid excess inductance that might exhibit enough inductive reactance to prevent charge bleed-off rapidly enough to protect from lightning strikes or energized lines coming in to contact with another conductor. A lot of people criticize people like us for "over thinking" everything, but how many of them have had discomfort or inconvenience spared because someone bothered to go the extra distance to do the hard thinking?
One particularly interesting aspect of my read through the book was learning how many things have changed since my electrician days back in the 1970s, prior to embarking on an electronics career. My experience was limited to residential and light commercial jobs. In my day, ground fault circuit interrupters (GFCIs) were just coming into existence and were required primarily in bathrooms and outdoor locations. Now they are required in kitchens and many other places. Arc fault circuit interrupters (AFCIs) were a gleam in the eye of some design engineer. Today, they are required in all living areas of a house. Dead-end switch configurations now require a neutral wire to be present in the box whether it is used or not. A simple weatherproof cover on an outside receptacle is no longer sufficient; now one that protects the entire plug (not just the receptacle) from rain is required. Since a minimum of two separate, 20 A circuits are (and were) required in a kitchen, on low-dollar installations we would satisfy the 20 A dining room circuit requirement simultaneously by sharing a circuit between the DR and the kitchen. No more. Now, bathroom circuits have to be 20 A, not 15 A. Would you guess that ground connections that rely solely on solder are prohibited? Weld it, wire nut it, secure it with screws, or use a bolted coupler. Did you know that the motor on your submersible pump is located below the impeller because of the guaranteed cooling requirement set forth in the NEC? All this I learned in David's fine book.
Believe it or not, I bookmarked twice as many topics as addressed here, but it would take too long to discuss them all. Whether you are planning to take the Master Electrician exam, are a practicing apprentice or journeyman electrician, or ever find yourself needing to perform incidental electrical wiring tasks, get "2011 NEC Chapter-by-Chapter" and read it... at least thumb through it. If you're anything like me, you will be glad you did. Thanks, David, for this fine book!
Written by Kirt Blattenberger
January 5, 2012
Note: David, with whom I have had no prior contact, contacted me to ask if I would write a review of his book, and I agreed to do so. He provided a complimentary copy of the book for me to read. A copy of this review is also on Amazon.com
Please see also my article, "Trade School vs. College?".
These items are an archive of past Topical Smorgasbord items that have appeared on the RF Cafe homepage. In keeping with the "cafe" genre, these tidbits of information are truly a smorgasbord of topics. They all pertain to topics that are related to the general engineering and science theme of RF Cafe. Note: There is also a huge collection of my 'Factoids' (aka 'Kirt's Cogitations') that might interest you as well.