Feeling overwhelmed by all the formulas you think you need to memorize for the electrical exam?
When it comes to preparing for the electrical licensing exam, test takers often feel overwhelmed by the idea of having to memorize dozens of formulas. The good news? You really only need to master Ohm’s Law and the Power Wheel (PIE chart) to handle nearly every calculation question on the test.
One of the most useful forms is P ÷ (I × E) — power divided by current times voltage. This formula plays a critical role in a variety of calculations: sizing transformers, calculating demand loads, determining the number of circuits in a dwelling, evaluating service sizes, and choosing the correct wire size based on appliance wattage.
Rather than trying to memorize every formula in the NEC, focus on understanding how and when to use the PIE chart. With this knowledge, you'll be able to break down even the most intimidating math questions with confidence and speed.
The P ÷ (I × E) formula helps you solve:
✅ Transformer sizing
✅ Demand load calculations
✅ Service calculations
✅ Circuit count for a dwelling
✅ Wire sizing based on appliance wattage
Simplify your prep. Focus on what actually shows up on the test.
