What Math Do Electricians Use? (4 Real-World Examples)

This article will provide real-world examples of how electricians use math theory and calculations on the job.

It’s important for electricians to be proficient in math skills in order to accurately plan, design, and install electrical systems. Electricians may also use specialized software and tools to perform these calculations. As an introduction, and in specific terms, electricians mostly utilize the following math theory:

1. Algebra: Electricians use algebra to solve equations and perform calculations related to electrical circuits.
2. Geometry: Electricians use geometry to measure and calculate the dimensions of electrical components and materials, such as wire and cable.
3. Trigonometry: Electricians use trigonometry to calculate angles and make precise measurements, particularly when working with electrical installations that involve heights or slopes.
4. Calculus: Electricians may use calculus to analyze and solve more complex problems related to electrical systems.
5. Arithmetic: Electricians use basic arithmetic skills, such as addition, subtraction, multiplication, and division, to perform calculations related to electrical work.

I understand that if you’re considering becoming an electrician, all these “intimidating” math terms can seem overwhelming – particularly for first-time electrical trade schoolers. I will, however, encourage you to continue reading because I will provide some real-world examples of how simple and “learnable” all of this math really is.

What Type of Math Do Electricians Use?

While most apprentice electricians are taught the fundamental concepts of electric circuits, calculations, and methods in electrical trade school, only a portion of this knowledge is actually applied in their daily work.

Electricians must use math in a variety of ways, including determining the amount of cable needed for a project, measuring distances, and ensuring that electrical standards are met. Math is also used by electricians to calculate the correct dimensions for cables based on specific lengths.

An electrician’s job involves a bit more than simply installing a power outlet or connecting a wire to a ceiling lamp. An electrician must also make sure that the proper materials are used for the right project. Materials, though, are actually frequently provided when you are hired by a certified Master electrician. This means that the correct cables have already been chosen for you.

The primary responsibility of an electrician is to properly install electrical components and materials. So don’t be concerned. To work as an electrician, you will not need the skills of an electrical engineer. However, being an electrician frequently necessitates some basic mathematical abilities.

Example 1: Measuring How Many Cable Ties Are Needed (Easy)

One of the most common types of math skills an electrician encounters is measuring lengths, heights, widths, and depths. Electricians need to know how to measure and calculate the length of wire needed for a specific project. Luckily electricians have a lot of helpful tools that help us get through the task of measuring these things. The most commonly used tools for measuring include:

• Folding rule (also called a yard-stick)
• Measuring tape
• Laser ruler
• Calculator (oftentimes a smartphone calculator is sufficient)
• 90-degree ruler

Measuring tools come in very handy in numerous ways in installing electrical equipment. A folding ruler is for example used for installing shorter distances of cable trays. While installing cable trays and placing visible cables on a wall or building, a folding ruler is used to make the right distances between cable ties.

A standard, that electricians use is the distance for cable ties to be around 20 inches or 50 cm. If you have a distance for a cable to run along of say 5 meters, measurement and calculation could simply look like this:

500 cm (distance) / 50cm (distance between cable ties)= 10 cable clips are needed for this particular job

Example 2: Finding the Length of a cable (Easy)

Measurement and counting combined with some simple math are also commonly used when figuring out the length of a cable. Luckily today, cables are being provided with visible numbers, which helps an electrician to know the precise length.

The method is to first get an approximate overview of the length needed by either using a distance ruler with a laser or simply by “taking a walk” and counting the steps (most electricians do this). As a general rule, there is 100cm between each step which can then easily be multiplied. So the ridiculously simple equation will look like this:

87 meters cable is needed: 356 meters  (current visible number on cable) – 87 m = 269 m (269 meters being the visible number you will see on the cable to cut off the correct length for the job.

Example 3: Finding the Length of a Cable

An easy way to approximate the length of a cable (with no numbers to do the previous calculation) an electrician can find the length of a cable is to use some simple geometry. Say we have a bundle of cables, but we want to use 50 meters, an electrician could use a combination of geometry and simple counting.

Measure the diameter of the cable bundle = 50cm

Calculate the circumference with algebra: O (circumference):  50cm diameter * 3.14 (the number of pi) = 157.5cm

Calculate the number of circumferences needed: 5000cm (length needed) / 157cm = 31 circumferences of cable needed.

This concludes that we need to pick 31 circumferences from the cable bundle to have what we need.

As shown, the math applied by electricians (in the real world) is not in any shape or form spectacular. Although it is not enormously advanced, an electrician needs to be structured and orderly-oriented to get the job done right.

Example 4: Determining the Correct Cable Size

Electricians also need to figure out how thick the wires should be for electrical circuits. This involves some math about electricity. They learn this more advanced stuff in electrical trade school to know what’s happening behind the scenes in electrical work.

Imagine an electrician is putting in a new electrical circuit at a house. This circuit will power things like a washing machine, dryer, and water heater. The electrician splits the circuit into two groups: one for the washing machine and dryer, and the other for the water heater. The washing machine and dryer together use 5,000 watts, and the water heater uses 4,500 watts.

To pick the correct wire size, the electrician first adds up how much power each group uses:

Group 1: 5,000 watts
Group 2: 4,500 watts

Then, they need to find out how much electric current (like the flow of electricity) goes through each group. They use a formula:

Electric Current = Power / Voltage

For this circuit, it’s going to be powered by a 240-volt outlet. So, the electrician can use this formula for each group:

Group 1: Electric Current = 5,000 watts / 240 volts = 20.83 amps
Group 2: Electric Current = 4,500 watts / 240 volts = 18.75 amps

Now comes the part about choosing the right cable size. There are rules called the National Electrical Code (NEC) that help with this. It says different wires can handle different amounts of current based on how long they are. For example, it might say a certain kind of wire, like 12-gauge, can handle up to 20 amps for a certain distance. Another kind, like 14-gauge, can handle up to 15 amps for a bit longer distance.

In this situation, the electrician knows Group 1 needs wires for 20.83 amps and Group 2 needs wires for 18.75 amps. They also know the wires have to reach all the appliances in each group.

Conclusion: Following the NEC rules, they might decide to use 12-gauge wire for Group 1 and 14-gauge wire for Group 2. This way, the wires can handle the electricity safely without causing problems.

Math Used by Electricians: Words of Advice

If you are someone who is strongly considering a career as an electrician but has previously been struggling with math, in high school or otherwise, you should not see this as an issue. Everything can be learned, and the methods for developing the skills in math will be gradually learned over the course of your apprenticeship.

The exciting thing about math used by electricians is that we use it in both a theoretical and practical sense. This also provides extra motivation and makes the learning curve a fun experience.