TABLE OF CONTENTS CHAPTER 1 ELECTRICAL THEORY About This Textbook...xi. Passing Your Exam...xiv. How to Use the National Electrical Code...

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1 TABLE OF CONTENTS About This Textbook...xi Passing Your Exam...xiv How to Use the National Electrical Code... 1 CHAPTER 1 ELECTRICAL THEORY... 7 Unit 1 Electrician s Math and Basic Electrical Formulas... 9 Part A Electrician s Math... 9 Introduction Whole Numbers Decimals Fractions Percentages Multiplier Percent Increase Reciprocals Squaring a Number Parentheses Square Root Volume Kilo Rounding Off Testing Your Answer for Reasonableness Part B Basic Electrical Circuits and Formulas Introduction Electrical Circuit Power Source Conductance Circuit Resistance Ohm s Law Ohm s Law and Alternating Current Ohm s Law Formula Circle PIE Formula Circle Formula Wheel Using the Formula Wheel Power Losses of Conductors Cost of Power Conclusion Unit 1 Review Questions Unit 1 Challenge Questions NEC Practice Quiz 1 Straight Order [ ] NEC Practice Quiz 1 Random Order [ ] NEC Challenge Quiz 1 [90.1 Chapter 9] Unit 2 Electrical Circuits Part A Series Circuits Introduction Practical Uses of the Series Circuit Understanding Series Calculations Series Circuit Calculations Power Calculations Variations Series Circuit Notes Series-Connected Power Supplies Part B Parallel Circuits Introduction Practical Uses of the Parallel Circuit Understanding Parallel Calculations Circuit Resistance Parallel Circuit Notes Parallel-Connected Power Supplies Part C Series-Parallel Circuits Introduction Review of Series and Parallel Circuits Working With Series-Parallel Circuits Voltage Part D Multiwire Branch Circuits Introduction Neutral Conductor Grounded Conductor Mike Holt Enterprises NEC.CODE ( ) v

2 2.18 Current Flow on the Neutral Conductor Balanced Systems Unbalanced Current Multiwire Branch Circuits Dangers of Multiwire Branch Circuits NEC Requirements Conclusion Unit 2 Review Questions Unit 2 Challenge Questions NEC Practice Quiz 2 Straight Order [ ] NEC Practice Quiz 2 Random Order [ ] NEC Challenge Quiz 2 [90.1 Chapter 9] Unit 3 Understanding Alternating Current Part A Understanding Alternating Current Introduction Current Flow Why Alternating Current is Used How Alternating Current is Produced Alternating-Current Generator Waveform Sine Wave Frequency Phase Degrees Lead or Lag Values of Alternating Current Part B Capacitance Introduction Charged Capacitor Electric Field Discharging a Capacitor Determining Capacitance Uses of Capacitors Phase Relationship Part C Induction Introduction Self-Induction Induced Voltage and Applied Current Conductor Resistance, Alternating-Current Circuits Conductor Shape Magnetic Cores Self-Induced and Applied Voltage Inductive Reactance Phase Relationship Uses of Induction Part D Power Factor Introduction Apparent Power (Volt-Amperes) True Power (Watts) Power Factor Unity Power Factor Power Factor Formulas Cost of True Power Effects of Power Factor Part E Efficiency Introduction Efficiency Formulas Conclusion Unit 3 Review Questions Unit 3 Challenge Questions NEC Practice Quiz 3 Straight Order [ ] NEC Practice Quiz 3 Random Order [ ] NEC Challenge Quiz 3 [90.1 Chapter 9] Unit 4 Motors and Transformers Part A Motor Basics Introduction Motor Principles Dual-Voltage Alternating-Current Motors Motor Horsepower Ratings Motor Current Ratings Calculating Motor FLA Motor-Starting Current Motor-Running Current Motor Locked-Rotor Current (LRC) Motor Overload Protection Direct-Current Motor Principles Direct-Current Motor Types Reversing the Rotation of a Direct-Current Motor Alternating-Current Induction Motor Alternating-Current Motor Types Reversing the Rotation of an Alternating-Current Motor vi Mike Holt s Illustrated Guide to Electrical Exam Preparation, Based on the 2017 NEC

3 Part B Transformers Introduction Transformer Basics Secondary Induced Voltage Efficiency Transformer Turns Ratio Power Losses Transformer kva Rating Transformer Current Flow Transformer Current Rating Autotransformers Conclusion Unit 4 Review Questions Unit 4 Challenge Questions NEC Practice Quiz 4 Straight Order [ ] NEC Practice Quiz 4 Random Order [ ] NEC Challenge Quiz 4 [90.1 Chapter 9] CHAPTER 2 NEC CALCULATIONS Unit 5 Raceway and Box Calculations Part A Raceway Sizing Introduction Insulated Conductors and Fixture Wires Dimensions Chapter 9, Tables 5 and Raceway Properties Raceway with Different Size Conductors Raceway Sizing Steps Multiconductor and Optical Cables Chapter 9, Note (5) and Note (9) Cables with Elliptical Cross Section Chapter 9, Note (9) Sizing Raceways Using Annex C Conductor Jamming Chapter 9, Table 1, Note Sizing Wireways Sizing Wireway for Conductor Bending Radius [376.23(A)] Tips for Raceway Calculations Part B Outlet Box Fill Introduction Sizing Box Conductors All the Same Size Box Fill Calculations [314.16(B)] Outlet Box Sizing Steps Part C Pull Boxes, Junction Boxes, and Conduit Bodies Introduction Pull/Junction Box Sizing Requirements Pull/Junction Box Sizing Tips Pull Box Examples Summary Conclusion Unit 5 Review Questions Unit 5 Challenge Questions NEC Practice Quiz 5 Straight Order [ ] NEC Practice Quiz 5 Random Order [ ] NEC Challenge Quiz 5 [90.1 Chapter 9] Unit 6 Conductor Sizing and Protection Calculations Part A Conductor Requirements Introduction Conductor Insulation Conductor Sizes Smallest Conductor Size [ ] Conductor Size Equipment Terminal Rating [110.14(C)] Overcurrent Protection [Article 240] Part B Conductor Ampacity Introduction Conductor Ampacity Ambient Temperature Correction [310.15(B)(2)(a)] Rooftop Temperature Adder [310.15(B)(3)(c)] Ampacity Adjustment [310.15(B)(3)(a)] Combining Ambient Temperature and Conductor Bundling Adjustments Current Carrying Conductors Wireway Conductor Ampacity Adjustment Conductor Ampacity Summary Overcurrent Protection and Conductor Sizing Feeder Tap Rules Conclusion Unit 6 Review Questions Unit 6 Challenge Questions NEC Practice Quiz 6 Straight Order [ ] NEC Practice Quiz 6 Random Order [ ] NEC Challenge Quiz 6 [90.1 Chapter 9] Mike Holt Enterprises NEC.CODE ( ) vii

4 Unit 7 Motor and Air Conditioning Calculations Part A Motor Calculations Scope of Article Motor Full Load Current (FLC) [430.6(A)(1)] Motor Nameplate Full Load Amperes (FLA) [430.6(A)(2)] Branch Circuit Conductor Sizing [430.22] Feeder Conductor Sizing [430.24] Overcurrent Protection Overload Protection Sizing Branch Circuit Short Circuit and Ground Fault Protection Branch-Circuit Summary Combined Branch Circuit Overcurrent Protection [430.55] Feeder Short Circuit and Ground Fault Protection [430.62] Motor VA Calculations Adjustable Speed Drives Fire Pump Motor Circuits Part B Air Conditioning Calculations Scope of Article Multimotor Equipment [440.4(B)] Motor Compressor and Other Motors Short Circuit and Ground Fault Protection [440.22(B)(1)] Motor Compressor and Other Motors Conductor Size [440.33] Conclusion Unit 7 Review Questions Unit 7 Challenge Questions NEC Practice Quiz 7 Straight Order [ ] NEC Practice Quiz 7 Random Order [ ] NEC Challenge Quiz 7 Quiz [90.1 Chapter 9] Unit 8 Voltage Drop Calculations Part A Conductor Resistance Calculations Introduction Conductor Size Conductor Resistance Alternating Current Conductor Resistance Alternating Current Resistance [Chapter 9, Table 9] Alternating Current versus Direct Current Resistance Part B Voltage Drop Considerations Introduction NEC Voltage Drop Recommendations Determining Circuit Conductors Voltage Drop Ohm s Law Method Sizing Conductors to Account for Voltage Drop Determining Circuit Conductors Voltage Drop Formula Method Limiting Conductor Length (Distance) to Minimize Voltage Drop Limiting Current to Limit Voltage Drop Conclusion Unit 8 Review Questions Unit 8 Challenge Questions NEC Practice Quiz 8 Straight Order [ ] NEC Practice Quiz 8 Random Order [ ] NEC Challenge Quiz 8 [90.1 Chapter 9] Unit 9 Dwelling Unit Calculations Part A Standard Method Load Calculations [Article 220, Part III] Introduction General Lighting and General Use Receptacle Demand Load [220.42] Appliance Demand Load [220.53] Dryer Demand Load [220.54] Cooking Equipment Demand Load [220.55] Air Conditioning versus Heat Demand Load Service Conductor Sizing [310.15(B)(7)] Standard Method Load Calculations Example [Article 220, Part III] Part B Optional Method Load Calculations [Article 220, Part IV] Introduction Dwelling Unit Optional Load Calculation [220.82] Dwelling Unit Optional Load Calculation [220.82] Example Existing Dwelling Unit Optional Load Calculation [220.83] Existing Dwelling Unit Optional Load Calculation [220.83] Example Part C Neutral Load Calculations Service Neutral Calculations Ranges and Dryers [220.61] Neutral Service and Feeder Calculation [220.61(B)] viii Mike Holt s Illustrated Guide to Electrical Exam Preparation, Based on the 2017 NEC

5 Conclusion Unit 9 Review Questions Unit 9 Challenge Questions NEC Practice Quiz 9 Straight Order [ ] NEC Practice Quiz 9 Random Order [ ] NEC Challenge Quiz 9 [90.1 Chapter 9] CHAPTER 3 ADVANCED NEC CALCULATIONS Unit 10 Multifamily Dwelling Calculations Part A Standard Method Load Calculations [Article 220, Part III] Introduction General Lighting and General Use Receptacle Demand Load [220.42] Appliance Demand Load [220.53] Dryer Demand Load [220.54] Cooking Equipment Demand Load [220.55] Air Conditioning versus Heat Demand Load [220.60] Service Conductor Sizing [310.15(B)(16)] Multifamily Dwelling Calculations Standard Method Examples Part B Optional Method Load Calculations [Article 220, Part IV] Introduction Multifamily Dwelling Optional Load Calculations [220.84] Multifamily Dwelling Optional Method Examples [220.84] Two Family Dwelling Units [220.85] Part C Neutral Load Calculations Dryers and Cooking Equipment [220.61] Service Neutral [220.61(B)] Conclusion Unit 10 Review Questions Unit 10 Challenge Questions NEC Practice Quiz 10 Straight Order [ ] NEC Practice Quiz 10 Random Order [ ] NEC Challenge Quiz 10 [90.1 Chapter 9] Unit 11 Commercial Calculations Part A General Introduction Lighting Demand Factors [Tables and ] Lighting Load 100% Demand Sign Circuit [220.14(F) and 600.5] Show Window Lighting [220.14(G)] Multioutlet Receptacle Assembly [220.14(H)] Receptacle Load [220.14(I) and ] Banks and Offices Receptacle Demand Load [220.14(K)] Part B Examples Bank/Office Buildings Manufactured Home Parks [550.31] Recreational Vehicle Parks [551.73] Marinas [555.12] Part C Optional Method New Restaurant Feeder/ Service Load Calculations Introduction New Restaurant Optional Method [220.88] Part D Welders Introduction Arc Welders Resistance Welders Light Industrial Calculations School Optional Method Load Calculations [220.86] Conclusion Unit 11 Review Questions Unit 11 Challenge Questions NEC Challenge Test 1 [Article 90 Chapter 9] NEC Challenge Test 2 [Article 90 Chapter 9] Unit 12 Transformer Calculations Part A General Introduction Transformer Basics Delta Connected Transformers Wye Connected Transformers Transformer kva Rating Line Currents Mike Holt Enterprises NEC.CODE ( ) ix

6 Part B NEC Requirements Transformer Overcurrent Protection Primary Conductor Sizing Secondary Conductor Sizing Grounding and Bonding Conclusion Unit 12 Review Questions Unit 12 Challenge Questions NEC Challenge Test 3 [Article 90 Chapter 9] NEC Challenge Test 4 [Article 90 Chapter 9] CHAPTER 4 NEC CHALLENGE EXAMS NEC Challenge Exam 1 [Article 90 Chapter 9] NEC Challenge Exam 2 [Article 90 Chapter 9] NEC Challenge Exam 3 [Article 90 Chapter 9] NEC Challenge Exam 4 [Article 90 Chapter 9] NEC Challenge Exam 5 [Article 90 Chapter 9] NEC Challenge Exam 6 [Article 90 Chapter 9] NEC Challenge Exam 7 [Article 90 Chapter 9] NEC Challenge Exam 8 [Article 90 Chapter 9] NEC Challenge Exam 9 [Article 90 Chapter 9] NEC Challenge Exam 10 [Article 90 Chapter 9] NEC Challenge Exam 11 [Article 90 Chapter 9] NEC Challenge Exam 12 [Article 90 Chapter 9] NEC Challenge Exam 13 [Article 90 Chapter 9] NEC Challenge Exam 14 [Article 90 Chapter 9] NEC Challenge Exam 15 [Article 90 Chapter 9] NEC Challenge Exam 16 [Article 90 Chapter 9] NEC Challenge Exam 17 [Article 90 Chapter 9] NEC Challenge Exam 18 [Article 90 Chapter 9] NEC Challenge Exam 19 [Article 90 Chapter 9] NEC Challenge Exam 20 [Article 90 Chapter 9] NEC Challenge Exam 21 [Article 90 Chapter 9] NEC Challenge Exam 22 [Article 90 Chapter 9] NEC Challenge Exam 23 [Article 90 Chapter 9] NEC Challenge Exam 24 [Article 90 Chapter 9] NEC Challenge Exam 25 [Article 90 Chapter 9] NEC Challenge Exam 26 [Article 90 Chapter 9] NEC Challenge Exam 27 [Article 90 Chapter 9] About the Author About the Illustrator About the Mike Holt Team x Mike Holt s Illustrated Guide to Electrical Exam Preparation, Based on the 2017 NEC