Electrical Calculations and Review 6 Credits
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6 CEUs
Course Description:
This comprehensive 6-hour course provides electricians with a detailed review of essential electrical calculations required for field practice and NEC compliance. Participants will strengthen their understanding of core electrical theory, mathematical relationships, and code-based calculation methods used in design, installation, and troubleshooting.
Topics include application of Ohm’s Law, the PIE formula, and power factor analysis, as well as in-depth calculations for motors, transformers, raceways, conductors, and voltage drop. Students will review NEC tables and articles governing conductor sizing, ampacity adjustments, overcurrent protection, and box fill. The course reinforces how to perform accurate electrical load, conductor, and protection device calculations using current NEC references.
By the end of this class, participants will be confident in applying formulas, interpreting NEC tables, and performing real-world calculations that ensure safety, efficiency, and compliance in electrical installations.
Learning Objectives: Upon completion of this course, participants will be able to:
1. Apply Basic Electrical Formulas
Calculate electrical circuit values using Ohm’s Law and power formulas (PIE, EIR, etc.).
Determine circuit conductance, resistance, and power losses in conductors.
Explain and apply the concept of power factor and its impact on circuit efficiency.
2. Analyze Electrical Circuits
Identify and calculate characteristics of series, parallel, and series-parallel circuits.
Perform load and current distribution calculations for multiwire branch circuits.
3. Understand Alternating Current (AC) Characteristics
Explain the effects of capacitance, inductance, and reactance in AC circuits.
Calculate power factor, efficiency, and efficiency ratios in AC systems.
4. Perform Motor and Transformer Calculations
Conduct motor VA, FLA, and overcurrent protection calculations using NEC Article 430.
Determine conductor sizes, feeder protection, and overload device ratings for motors.
Apply NEC rules for single and multiple motor circuits, including 430.22(A), 430.24, and 430.61.
Perform transformer sizing, KVA rating, turn ratio, and secondary voltage calculations.
Analyze autotransformer circuits and calculate power losses.
5. Raceway and Box Calculations
Calculate raceway fill, nipple fill, and box fill in compliance with Article 314.16.
Determine box sizes for same-size and mixed conductor sizes using NEC tables.
Size pull and junction boxes according to Article 314.28 and conduit entry requirements.
6. Conductor Sizing and Protection
Apply NEC rules for conductor insulation, ampacity, and parallel conductors (Articles 110.6, 310.4, 310.15).
Calculate conductor ampacity adjustments for ambient temperature and bundling (Table 310.16, 310.15(B)(2)(a)).
Evaluate voltage drop effects on conductor sizing and performance per NEC 210.19(A)(1).
7. Voltage Drop Calculations
Determine conductor resistance and calculate voltage drop under varying loads.
Size conductors to minimize voltage loss and comply with NEC voltage-drop recommendations.
Apply methods to limit conductor length and control current to maintain system efficiency.
Extend existing circuits while maintaining acceptable voltage-drop limits.
