# Apprentice's Guide to Calculations

June 4, 2024
From the EC&M e-books library: Learn the basics and test your knowledge with Trainer Harold De Loach

In the first editorial e-book of 2024, we highlighted some of the most popular articles from EC&M contributor, master electrician, electrical trainer/instructor, and founder/director of The Academy of Industrial Arts L.L.C., Harold De Loach. That e-book, “Apprentice’s Guide to Entering the Electrical Industry,” highlighted the best advice, tips, and tricks for anyone new to the trade from De Loach’s training articles. If you haven’t already read that compilation of articles, I encourage you to check it out in the e-book library available on the Members Only section of our website at ecmweb.com/ebook-library.

Building upon the last “Apprentice’s Guide” series, this second installment of training e-books presents Harold De Loach’s most popular and engaging articles on the ever-important topic of performing electrical calculations.

While our last e-book focused on fundamentals needed to enter the electrical industry, this one zeroes in on a skill every electrical apprentice needs to thrive in their career. Calculations are a crucial part of the job. It may seem daunting at first, but, as De Loach puts it, “When it comes to performing calculations on the job, it may seem as if the boss is working some kind of magic, but that’s not the case. He or she is simply using basic math and simple formulas found in Annex D at the rear of your Code book.” Harold breaks down that “simple math” in the first article of this collection, “The Apprentice’s Guide to Article 220.”

“Introduction to Commercial Service Calculations” and “The Apprentice’s Guide to Service Feeder Calculations” go on to take readers through different types of calculations step by step. Each article also includes a practice question with guided steps on how to reach the solution so you can get some hands-on practice before trying these calculations in the field. Or, if you’re already experienced with calculations, these questions are a good way to keep your skills sharp.

This collection closes with “The Apprentice’s Guide to NEC Chapter 4.” As De Loach writes, this chapter of the NEC “contains all of the installation guidelines for everyday stuff or equipment that controls or consumes electricity. As an electrician, these are items you see throughout your daily routine no matter what sector of the industry you work in.” It’s a great overview and also contains a practice question to test your knowledge.

Whether you’re a calculations expert or novice, get your pencils and calculators out—and follow along with Harold De Loach in your quest to become a master of calculations.

These articles reference the 2017 NEC because the Philadelphia area—the jurisdiction where Harold De Loach teaches and works—still operates under that version of the Code.