Chapter 1 Electrical Theory and Part C Series Parallel and Code Questions Multiwire Branch Circuits Unit 1 Electrician s Math

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1 Chapter 1 Electrical Theory and Code Questions 1 Unit 1 Electrician s Math and Basic Electrical Formulas 3 Part A Electrician s Math Fractions Kilo Knowing Your Answer Multiplier Parentheses Percentages Percent Increase Percentage Reciprocals Rounding Squaring Square Root 7 Part B Basic Electrical Formulas Electrical Circuit Electron Flow Power Source Conductance and Resistance Electrical Circuit Values Ohm s Law I = E/R Pie Circle Formula Formula Wheel Power Changes With the Square of the Voltage Electric Meters 15 Unit 1 Calculations Questions 18 Unit 1 Code Questions 25 Unit 1 - NEC Exam Unit 2 Electrical Circuits 39 Part A Series Circuits Understanding Series Calculations Series Circuit Summary 42 Part B Parallel Circuit Parallel Circuits Practical Uses Parallel Circuits Understanding Parallel Circuit Resistance Calculations Parallel Circuit Summary 47 Part C Series Parallel and Multiwire Branch Circuits Series and Parallel Circuits Review Series-Parallel Circuit Resistance Calculations 48 Part D Multiwire Branch Circuits Neutral Current Calculations Multiwire Branch Circuit - Danger 52 Unit 2 Calculations Questions 54 Unit 2 Code Questions 59 Unit 2 NEC Exam Code Order Unit 2 NEC Exam Random Order Unit 3 Understanding Alternating Current 77 Part A Alternating Current Fundamentals Current Flow Alternating Current Alternating Current Generator Waveform Armature Turning Frequency Phase In and Out Phase Differences in Degrees Values of Alternating Current 81 Part B Induction Induced Voltage and Applied Current Conductor Impedance Induction and Conductor Shape Induction and Magnetic Cores 83 Part C Capacitance Capacitor Charge, Testing and Discharging Use of Capacitors 86 Part D Power Factor and Efficiency Apparent Power (Volt-Ampere) Power Factor True Power (Watts) Efficiency 90 Unit 3 Calculations Questions 92 iv

2 Unit 3 Code Questions 100 Code Order Random Order Unit 4 Motors and Transformers 115 Part A Motors Motor Speed Control Reversing a Direct-Current Motor Alternating-Current Motors Reversing Alternating-Current Motors Motor Volt-Ampere Calculations Motor Horsepower/Watts Motor Nameplate Ampere 119 Part B Transformer Basics Transformer Primary and Secondary Transformer Secondary and Primary Voltage Autotransformers Transformer Power Losses Transformer Turns Ratio Transformer kva Rating Transformer Current 123 Unit 4 Calculations Questions 125 Unit 4 Code Questions 132 Unit 4 NEC Exam Code Order Random Order Chapter 2 NEC Calculations and Code Questions 149 Unit 5 Raceway, Outlet Box, and Junction Boxes Calculations 151 Part A Raceway Fill Understanding The National Electrical Code, Chapter Raceway and Nipple Calculation Existing Raceway Calculation Raceway Calculations Tips 159 Part B Outlet Box Fill Calculations Box Sizing Conductors All the Same Size [Table (A)] Box Sizing Conductor Equivalents [314.16(B)] Box Sizing Different Size Conductors [314.16(B)] 162 Part C Pull, Junction Boxes, And Conduit Bodies Pull and Junction Box Size Calculations Pull and Junction Box Depth [314.28(A)(2), Exception] Pull and Junction Box Sizing Tips Pull and Junction Box Examples 166 Unit 5 Calculations Questions 168 Unit 5 Code Questions 172 Unit 5 NEC Exam Code Order Unit 5 NEC Exam Random Order Unit 6 Conductor Sizing and Protection Calculations 191 Part A General Conductor Requirements Conductor Insulation Property [Table ] Conductor Allowable Ampacity [310.15] Conductor Sizing [110.6] Terminal Ratings [110.14(C)] Conductors in Parallel [310.4] Conductor Size Voltage Drop [210.19(A) FPN No. 4, and 215.2(B) FPN No. 2] Overcurrent Protection [Article 240] Overcurrent Protection of Conductors General Requirements [240.4] Overcurrent Protection of Conductors Specific Requirements Equipment Conductors Size and Protection Examples 202 Part B Conductor Ampacity Calculations Conductor Ampacity [310.10] Ambient Temperature Adjustment Factor [Table ] 203 v

3 6 13 Conductor Bundling Adjustment Factor [Table (B)(2)] Ambient Temperature and Conductor Bundling Adjustment Factors Current-Carrying Conductors Conductor Sizing Summary 209 Unit 6 Calculations Questions 210 Unit 6 Code Questions 215 Unit 6 NEC Exam Code Order Unit 6 NEC Exam Random Order Unit 7 Motor Calculations Motor Branch Circuit Conductors [430.22(A)] Motor Overcurrent Protection Motor Overload Protection [430.32(A)] Motor Branch Circuit Short-Circuit Ground- Fault Protection [430.52(C)(1)] Motor Feeder Conductor Size [430.24] Motor Feeder Protection [430.62(A)] Motor Highest Rated Motor [430.17] Motor Calculations Steps Motor Calculation Review Motor VA Calculations 243 Unit 7 Calculations Questions 245 Unit 7 Code Questions 249 Unit 7 NEC Exam Code Order Unit 7 NEC Exam Random Order Unit 8 Voltage Drop Calculations 269 Part A Conductor Resistance Calculations Conductor Resistance Conductor Resistance Direct Current Circuits, [Chapter 9, Table 8] Conductor Impedance Alternating Current Circuits Alternating Current Impedance As Compared To Direct Current Alternating Current Impedance [Chapter 9, Table 9 of the NEC] 272 Part B Voltage Drop Calculations Voltage Drop Considerations Voltage Drop NEC Recommendations Determining Circuit Conductors Voltage Drop Sizing Conductors to Prevent Excessive Voltage Drop Limiting Conductor Length to Limit Voltage Drop Limiting Current to Limit Voltage Drop Extending Circuits 281 Unit 8 Calculations Questions 283 Unit 8 Code Questions 288 Unit 8 NEC Exam Code Order Unit 8 NEC Exam Random Order Unit 9 Single-Family Dwelling Unit Load Calculations 305 Part A - General Requirements General Requirements Voltages [220.2(A)] Fraction of an Ampere [220.2(B)] Appliance (Small) Circuits [220.11(C)(1)] Cooking Equipment Branch Circuit [Table , Note 4] Laundry Receptacle(S) Circuit [220.11(C)(2)] Lighting and Receptacles 309 Part B - Standard Method Feeder/Service Load Calculations Dwelling Unit Feeder/Service Load Calculations (Part II of Article 220) Dwelling Unit Feeder/Service Calculations Examples 312 Part C - Optional Method Feeder/Service Load Calculations Dwelling Unit Optional Feeder/Service Calculations [220.30] 316 vi

4 9 11 Dwelling Unit Optional Calculation Examples Neutral Calculations General [220.22] 319 Unit 9 Calculations Questions 320 Unit 9 Code Questions 327 Unit 9 NEC Exam Code Order Unit 9 NEC Exam Random Order Chapter 3 Advanced NEC Calculations And Code Questions 345 Unit 10 Multifamily Dwelling Unit Load Calculations Multifamily Dwelling Unit Calculations Standard Method Multifamily Dwelling Units Calculation Examples Standard Method Multifamily Dwelling Units Calculation Sample Standard Method Multifamily Dwelling Unit Calculations [220.32] Optional Method Multifamily Dwelling Unit Example Questions [220.32] Optional Method 353 Unit 10 Calculations Questions 355 Unit 10 Code Questions 359 Unit 10 NEC Exam Code Order Unit 10 NEC Exam Random Order Unit 11 Commercial Load Calculations 379 Part A General General Requirements Conductor Ampacity [Article 100] Conductor Overcurrent Protection [240.3] Voltages [220.2(A)] Rounding an Ampere [220.2(B)] 380 Part B Loads Air-Conditioning Dryers Electric Heat Kitchen Equipment Laundry Equipment Lighting Demand Factors [Table 220.3(A) and ] Lighting Without Demand Factors [Table 220.3(A), and ] Lighting Miscellaneous Multioutlet Receptacle Assembly [220.3(B)(8)] Receptacles VA Load [220.13] Banks and Offices General Lighting and Receptacles Signs [220.3(B)(6) and 600.5] Neutral Calculations [220.22] 389 Part C Load Calculation Examples 390 Part D Load Calculation Examples 395 Unit 11 Calculations Questions 400 Unit 11 Code Questions 405 Unit 11 NEC Exam Code Order Unit 11 NEC Exam Random Order Unit 12 Delta/Delta and Delta/Wye Transformer Calculations Current Flow 429 Part A Delta/Delta Transformers Delta Transformer Voltage Delta High -Leg Delta Primary and Secondary Line Currents Delta Primary or Secondary Phase Currents Delta Phase versus Line Delta Current Triangle Delta Transformer Balancing Delta Transformer Sizing Delta Panel Schedule In kva Delta Panelboard and Conductor Sizing Delta Neutral Current Delta Maximum Unbalanced Load Delta/Delta Example 436 vii

5 Part B Delta/Wye Transformers Wye Transformer Voltage Wye Line and Phase Voltage Triangle Wye Transformers Current Wye Line Current Wye Phase Current Wye Phase Versus Line Current Wye Transformer Loading and Balancing Wye Transformer Sizing Wye Panel Schedule In kva Wye Panelboard and Conductor Sizing Wye Neutral Current Wye Maximum Unbalanced Load Delta/Wye Example Delta Versus Wye 447 Unit 12 Calculations Questions 448 Unit 12 Code Questions 456 Unit 12 NEC Exam Code Order Chap Unit 12 NEC Exam Random Order Chap NEC Final Exam 470 viii