Study Guides

Electrical Theory & NEC Code, Explained

Free in-depth guides covering electrical theory, NEC code articles, HVAC fundamentals, and exam concepts — with fully worked examples.

All Guides Electrician Math Explained

Electrician Math Explained

3 guides

Step-by-step calculation guides -- voltage drop, conduit fill, box fill, and more -- with fully worked examples for exam prep and the field.

Electrician Math Explained

Voltage Drop Calculations Explained

A deep, plain-English walkthrough of voltage drop calculations — why voltage drop matters, the VD = (2 x K x L x I) / CM formula explained from first principles, and 6 fully worked real-world examples.

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Electrician Math Explained

Conduit Fill Calculations Explained

Learn why conduit fill limits exist, how the fill-percentage rules work, and how to size conduit correctly with six fully worked examples covering EMT, PVC, mixed conductor sizes, and pulling new circuits into existing raceways.

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Electrician Math Explained

Box Fill Calculations Explained — NEC 314.16

Learn why box fill limits exist, how the volume-allowance method works for conductors, devices, clamps, and grounds, and walk through six fully worked examples for choosing the right box size.

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