How do you prepare to pass your electrical exam and get your license on the first try? How do you know which code articles and calculations you’ll need to understand and remember? You need to know how electrical exams are structured and what your score will tell the examiner about your competence to do quality […]
In order to really understand how to calculate the power factor or efficiency of any motor you must understand the difference between true power or output power and apparent power or input power. True Power = Output Power or the power that is used by the motor to do useful work. Apparent Power = Input Power […]
To answer this question you’ll need to know the relationship between phase and line voltage in a 3-phase, 4-wire wye secondary. Phase voltage (read between any line and the neutral) multiplied by the square-root of three or the constant 1.732 = line voltage. 120 phase volts x 1.732 = 208 line volts. This is the […]
Electrical Exam Test Taking Tips Most of us don’t take exams on a regular basis, so it is very easy to run out of time prior to finishing the exam. Here are some test taking tips that can help you manage your time and increase your chances of passing your electrical exam on the first […]
The goal of electrical exam prep is to be prepared to actually pass the exam. The best way to prepare to pass the exam is to focus on developing three main skills. Use key words in questions to locate NFPA 70 code reference answers quickly. Become comfortable answering questions that require the use of formulas. Lean the […]
Can You Answer This Commercial Service Exam Question? How many 20 ampere general lighting circuits are required by code to supply a 5,000 sq.ft. office? Solution: Step #1 Refer to NFPA Table 220.12 which requires a minimum of 3.5 va/sq.ft. for the general lighting load for office buildings. 5,000 sq.ft. x 3.5 va/sq.ft. = 17,500 va […]
Can You Answer This Three-Phase Transformer Exam Question? What is the turns ratio of a three-phase 4-wire delta-wye transformer, with a 480 volt primary and a 208 volt/120 volt secondary? Solution: A turns ratio is a way of quantifying the relationship between the number of turn of the coil making up the primary verses the […]
Plan for success by learning how to answer motor efficiency calculation and related questions on your exam. Can you answer these questions correctly? Question: What is the efficiency of a 5 hp-230 volt single-phase ac motor? Solution: Use the single-phase efficiency formula = 746 watts x Hp Rating/E x I = 746 watts x 5 […]
What is the demand load on the feeder for 1-14 kw 240 volt single-phase range installed in a dwelling unit? Solution: To answer this question correctly we need to know what the term demand as used in the code really means. The term demand always refers to a reduction from connected load. Which means that […]
Prevent Injuries from Contact of Overhead Power Lines with Metal Ladders According to the The National Institute for Occupational Safety and Health following the seven preventative safety protocols listed below can significantly improve work place safety. ■ Identify the location of overhead power lines as a routine part of all initial worksite surveys for jobs […]
