Friday, September 17, 2010

ICC Exam Part II


     The ICC does NOT score the same as any other exam. There is no one "unit" value for each question. In other words, in a 100 question test, each question has its own different value. Some are worth MORE and some are worth LESS than one point. For example, you may see an easy code question that is worth only 1/2 a point, yet a motor calculation question may carry a value of 1 & 3/4 points. No one outside of the ICC organization knows exactly what each question type is worth. We have seen evidence, however, that proves the "weighted score" method.

     Because of this type of scoring system, it becomes important to attempt to answer EVERY question. If you run out of time and leave 15 questions (as a random example) unanswered, you may actually be losing as much as possibly 20 points off your score.

     Experience shows us that most electricians initially answer code questions as a hunch or from experience. Many then continue to verify their answers by referencing their code book. Often times they'll then try to "talk themselves out" of their initial answer. Unfortunately for them, 90% of the time, their initial answers were the CORRECT ones!


     These two reasons, the scoring system and "gut reaction" answers; led us to create the following strategy that has been one of our greatest triumphs in our teaching method which sees a 95% first time passing rate success!

Your test strategy:
Upon first sitting and beginning your exam; leave your code book CLOSED!!! Do NOT touch it. Begin with question #1 and go through EVERY SINGLE question without STOPPING! Use the following "answering methodology:"

There are three ways to answer a question and 5 steps to complete on an ICC Electrical Test:

1) Answers that you KNOW for a fact are correct simply get answered and you then move on to the next question.
2) Answer the questions that you THINK you know (the so called "gut creations," but mark the (flagged) for later review.
3) Questions that stump you or that you have NO IDEA how to answer get left BLANK and flagged for later review.
4) AFTER completing your initial answering/review session, go back and begin answering ONLY THE QUESTIONS that you skipped and that have NO answer at all. You will find that your biggest block of time will then be spent on these questions.
5) After those have been answered, go back and begin reviewing & code verifying your "gut reaction" question block.

     This method will allow for three things. First it will assure that you've read and answered EVERY question. Next, it helps you devote your time to only those questions that need it the most. Finally, you'll be surprised at how many questions that you'll inadvertently "stumble" across the answers to, during your steps 4 and 5. At the very least, you'll be armed with the complete knowledge of ALL the questions contained on your electrical exam version.


(Part III coming up)

Thursday, September 16, 2010

"Secrets of the ICC Electrical Exams"

"What you don't know about HOW to take these exams CAN cost you 15 to 20 points off of your potential score."

     There are many states that offer the ICC Master Electrician's Exam as well as the Journeyman Electrician's Exams. Our firm has tracked and sat for many of these exams throughout the years. We have a better understanding of the author's questions and intentions, than the author probably has himself.

     Many electricians sit and cram for the weeks leading up to their exam and our experience has been that they average around only a 25% first time passing rate, when studying unassisted. This is NOT a call for alarm, rather it's simply to drive home a point: Getting back ground information on HOW to pass the ICC Electrical exam can be almost as important as KNOWING what information will be on the exam! Just knowing a few key items and understanding WHAT the authors are looking for in an answer can add 10 to 20 points to a final score. That can make a major difference in passing or having to continue to re-exam. We've seen electricians take the same exam 5, 6, even 7 or 8 times, and never really understand WHY they keep failing. We know exactly why, and that is what this blog is about.

     Half the battle of passing your exam is knowing the strategy and reasoning BEHIND the ICC's questions. We have seen many an experienced, knowledgeable master electrician fail their exam just because they don't know the mine fields to the ICC author's mindset. Even the way you should attack the questions during your first initial 15 to 45 minutes of your exam can have a critical and dramatic impact in your overall score.

     To give you a list of every detailed strategy, would take an entire book's worth of blogs. So we will look at just a few major issues and how to address them in this edition.

First, know how and when to apply Code "Exceptions" in formulating your answers.

Next, because of the weighted "scoring system" employed by the ICC exam makers, understand the importance of your initial            review/answering strategy.

Finally, watch out for questions within questions - be aware of "context" installation clues.


     NEC Articles are full of exceptions. There are exceptions to almost 50% of the most important sections in the code book. The use or disregarding of an exception can completely change an answer to an exam question. Motor overcurrent protection is a prime example. Article T430.52 is the table employed when sizing fuses or breakers to protect a motor installation. In fact, because there are TWO separate exceptions to this table, there will be THREE different answers to a circuit protection question. Alone, ignoring exceptions, T430.52 is a NOT TO EXCEED table of values. In other words, you would round DOWN in that instance. The use of exception #1 allows for the sizing UP to the next larger protective device size. Exception #2's use would allow for even larger calculable values but then they would require a DOWN sizing after all calculations have been performed. You now have 3 separate answers to the SAME exact motor installation. Now, do you choose to IGNORE the exception, employ exception #1, or implement the values in exception #2? You can see now why it is CRITICAL to understand how and when to apply exceptions.

Stay tuned for Part II coming this weekend! We'll get you up to speed for your exam and passed the first time!

Saturday, September 11, 2010

Small Branch Circuit Rules: Part II (cont'd from last week)

     We've reviewed the initial two items in our small branch circuit rules review blog, last week. In it, we looked at "fastened in place" and continuous load considerations. Next we will examine the types of connections and "Appliance" issues, to see how these impact our installation of an "Insta-Hot (tankless water heater).


     In a 15 or 20 Amp branch circuit, we would be allowed to use a cord cap and receptacle as our connection means. Staying mindful of our disconnect rules for appliances, we often use cord caps as both connecting and disconnecting means. Article 422.30 and 422.31(B) require us to provide a means to disconnect for ANY appliance that is over 300 VA or 1/8th HP (roughly anything over 2.5 Amps at 120V). In addition, Art. 422.33(A) allows us to utilize a "separable connector or an attachment plug..." as our disconnect method.
     On a 30 Amp branch circuit, the rules are similar to the 15 to 20 Amp's, EXCEPT with one item. IF a cord and plug connection is used, our 80% restriction is back in place. Therefore, a "hard-wired" 30 Amp circuit may serve loads up to and including 30 Amps, but a cord connected 30 Amp circuit is only rated for a maximum of 24 Amps. The "catch-22" trade off here, is that you would then have to provide a separate means of disconnect, other than a cord cap, to size the load from 25 Amps up to 30 Amps. There are no "fastened in place" restrictions explicitly mentioned for 30 Amp circuits, but it is implied from the cord cap restriction of 80%.

     Finally our focus turns to Article 422; "Appliances." Article 422 covers ALL occupancy types and appliances, even ones that are motor operated, and hermetically enclosed motors (such as compressor motors). It requires the rating of an "individual branch circuit" to be not less than the marked rating of the appliance, see 422.10(A).

     The specific section that deals with our tankless water heater is 422.10(E). The "Single-Non-motor-Operated Appliance" article gives three ways to comply.
1), Not to exceed that which is marked on the appliance.
2), Maximum size is 20 Amps if the appliance is 13.3 Amps or smaller.
3), Maximum size is 150% of the amperage of the appliance, where it is larger than 13.3 Amps AND where the maximum size is not already marked.
(Note: next standard size breaker is allowed under item 3, i.e. size UP when calculating your breaker size).

     One final word of caution, the location of the installation may require GFCI protection. If you utilize a receptacle and attachment plug connection method in bathrooms, garages, and some kitchen/utility areas, you must provide GFCI protection.
     To sum up this installation, a tankless water heater, rated at 20 Amps (2.4 KW) shall be allowed on a 20 Amp branch circuit. It would be fastened in place (most likely), thus either an attachment plug or direct wire connection would be allowed. Direct wiring of the appliance would however, require a separate disconnect and would likely add more expense and bother than a simple cord cap connection does. A 30 Amp tankless heater could be placed on a 30 Amp circuit, if it is direct wired with a separate disconnect, or a 40 Amp circuit if an attachment cord is utilized.


Don’t forget to check our blog next week.


-Mitch Tolbert

Thursday, September 9, 2010

"Small Branch Circuit Rules"


            "How do you correctly size a 20 Amp tankless water heater (Insta-Hot)? shouldn't you have to follow the "80%" rule and place it on a 30 Amp circuit with a #10 wire?"

     Several code questions arose this week about an insta-hot water heater installation. They are becoming a much more common installations these days. In order to answer the question, we must look at what the requirements are for small branch circuit sizing. This device itself is also considered an "Appliance," so we must also include considerations for appliances. Our main issues here are, what are the percentages of permissible loads on the circuit, continuous load or non-continuous load classification, plug and cap connections, permanent wiring and disconnecting means, and ultimately, "Appliance" considerations.


     We use the 80% rule quite frequently in the field to size branch circuits. It has become a 'rule of thumb.' However, there is some confusion in its application. There is no "blanket" rule that requires EVERY 15A and 20A circuit to be restricted to 80%. Article 210.23 under 'permissible loads,' states that we may supply ANY load for that which it is rated. This article in one of our key controlling sections.
     There are three critical main installation specifics used to navigate and correctly apply Article 210.23. (1), The first is whether or not the equipment is "fixed in place." Is the equipment readily mobile? Does it have coaster wheels or the like, or is it small enough to be easily repositioned? (2), Next we examine what loads are supplied by that branch circuit. Is it a dedicated circuit, feeding that piece of equipment alone? Are there other loads, such as lighting or general purpose outlets, on the same circuit? (3), Finally, is the equipment connection anticipated to be a cord and plug type or will it be "hard wired?"

                         Rule #1:    A cord and cap connected piece of equipment that is not "fastened in place" is restricted to 80% of the maximum branch circuit rating.

     That rule applies no matter what else the circuit feeds. Whether it is a dedicated branch circuit is not a consideration.

                         Rule #2:     If the equipment IS fastened in place AND if the circuit ALSO supplies lighting and/or other cord & plug connected equipment that is not fastened in place, the load is restricted to 50% of the branch circuit rating. For example, a room air conditioner, placed on a 20A branch circuit, would NOT be allowed to exceed 50% - or 10 Amps. Waste disposal (in sink garbage disposal) and dishwasher (non-mobile) would be two other good examples.

continuous & NON continuous LOAD CLASSIFICATIONS

       As you can see, the rules are specific and narrow. If the equipment IS 'fastened in place,' and the circuit supplies nothing else, then there is NOT any de-rating or percentage restriction required. This does, however, raise the next major issue of "continuous Load and Non-continuous Load" classification.
      The statement above ignores continuous load considerations. Equipment that operates, or can be anticipated to operate, for 3 hours or more, shall be classified as a continuous load. Further, Article 422.13 specifically classifies storage type water heaters as continuous loads. Any tank type water heater that is 120 gallons or smaller, MUST be considered a continuous load. (NOTE: this excludes "tankless water heaters.")
      Article 210.20(A) clarifies that continuous loads must be calculated at 125% of their rating. This 125% is the sister reciprocal of our 80% branch circuit restriction. 80% deals with our branch circuit size (ie. a 20A breaker is DIVIDED by 80% = 16 Amps). 125% deals with the load size itself, which comes from the opposite direction than our breaker sizing step. A load, sized at 16 Amps MULTIPLIED (multiplication is the reciprocal operation of division) by 125% = 20 Amps! In other words, 80% is a divider, 125% is a multiplier. If you know the branch circuit size, divide by 80%. If you know the equipment size, multiply by 125%.
      Thus a 20 Amp tank type water heater would result in a 25 Amp breaker size, along with #10 AWG (CU) conductors. 20A X 1.25 = 25 Amps. Sized at a 25 A breaker per 210.3 as an "individual branch circuit," and 240.6(A), "Standard Ampere Ratings," and 240.4(D)(7) - the so called "Small Conductor Rule."

     We will examine the rest of the rules in Part II. Look for it this Saturday!

-Mitch Tolbert

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