The idea behind developing the National Electrical Code, aside from fire and shock prevention, was to help explain how certain electrical devices or systems work the way they do.
For example: How does a GFCI work? Why can't an individual current-carrying conductor be installed in a metal raceway? Why can the protection for a 20-amp conductor feeding a motor be protected with 40-amp protection? Why can't a 15-amp single receptacle be installed on a 20-amp circuit? How can a bird rest on an energized power line and not be electrocuted? When you learn how and why elements of an electrical system work, you can better understand the National Electrical Code - and you'll be able to easily answer these questions and other questions like them given in most electrical exams.
In preparing for the electrical exam, a typical study plan should allow enough time to read each NEC reference at least three times - without putting you to sleep.
Read carefully the first time.
It may take some time.
In fact, the second time you read it should only take 10% of the first time.
Try and make the Code reference interesting by thinking of jobs you've done in the past and how the Code reference you're reading about applies to that job.
The reference will stick in your memory if you can link it to an on-the-job event.
Make a final review of all your references and notes on the day before the exam.
The more you review, the better you'll remember and the faster you'll be able to find the answers on the day of the test.
Everyone wants to finds things quickly in the NEC, but unless you become familiar with its organization, it will take considerable effort on your part, and you'll probably struggle during a timed electrical exam.
There are two ways to find things in the NEC.
You can use the Index, or look through the Table of Contents to locate your references.
For example, what if you want to look up grounding? You may not initially know that Article 250 concerns grounding, so the Table of Contents, which is organized by Article number (then subject), won't be very helpful to you at first.
I suggest using the Index until you know the Articles and their numbers.
A few examples of Articles you'll refer to frequently are: Article 230, Services Article 240, Overcurrent Protection Article 250, Grounding How to Read a Code Section Let's look at how the Code is organized and what you need to understand to find a code section.
What if the subject you want to research is indicated by 250.
20(A)(1) in the Index? What the heck does that mean? The numbers before the period indicate the Chapter and Article number.
Articles in each chapter all begin with the chapter number where you'll find them; Article 100 is in Chapter 1, Article 200 in Chapter 2, and so on.
The number after the period indicates the Section.
So, you're being sent to Section 20 of Article 250, in Chapter 2.
And finally, letters and numbers in parentheses indicate Subsections.
Articles An Article may also be broken down into Parts: I, II, III, IV, etc.
Then, under each Part are the Sections which are again broken down into Subsections.
The Part of an Article or Section isn't included in the Article number, but will often be included after the Article number in the Index.
For example, in the Index under Grounding, you'll find Bonding, 250-V.
That tells you that the subject of Bonding is covered in Part V of Article 250.
I find it helpful to circle in red each Part heading (marked with Roman numerals: I, II, III, etc.
) of every Article, and write that numeral at the top of the page.
That way, when you look for a particular Part of that Article, it'll be easier to find - especially during a timed test.
Now, let's look at my approach to studying the Code.
I decided to take a subject that's pretty dull, the NEC, and make it as interesting as possible.
Rather than starting at the beginning of the Code and going page by page, I'll skip around in the code book and deal with various subjects, like we're in a real classroom environment.
Services Every wiring system consists of three parts: the service, the feeders, and the branch circuits.
The minimum size of the service entrance conductors is determined by the total volt-amps of all feeder and branch circuit loads.
There are two methods used by a utility company to deliver power to a building: overhead service drop or underground service lateral.
Overhead Service-Drop Conductors (Part II, Article 230.
22) An overhead service drop, by definition, consists of the overhead conductors from the last pole to the structure, including the connection to the service entrance conductors at the service head (see Article 100 - Definitions).
The service entrance conductors are the conductors between the service-drop conductors and the service disconnecting means, which is located either inside or outside the building or structure.
The required location of the service disconnecting means for all structures is clearly defined.
It must be located at a readily-accessible location, and be as close as possible to where the service conductors enter the building.
See Article 230.
70(A).
Finding Information in the NEC Using the information we've covered so far, let's try finding the answer to a question pertaining to Article 230, Service.
When you're dealing with an electrical question, the easiest way to find the answer is to: First find the subject of the question.
Then, in the Index, find the word or words that best describe the subject of the question.
Finally, list the reference(s) following that word in the index on a piece of scratch paper.
Use the following breakdown to help analyze the question and find the answer: SUBJECT ________________ INDEX ________________ SECTION ________________ Using this method can help you study for the exam and pass with a higher score, as you'll be familiar with how to quickly find what you're searching for, in the shortest amount of time.