This article will provide an introduction to the most commonly used math and calculations that electricians must master.
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, ad in specific terms, electricians mostly utilize the following math theory:
- Algebra: Electricians use algebra to solve equations and perform calculations related to electrical circuits.
- Geometry: Electricians use geometry to measure and calculate the dimensions of electrical components and materials, such as wire and cable.
- Trigonometry: Electricians use trigonometry to calculate angles and make precise measurements, particularly when working with electrical installations that involve heights or slopes.
- Calculus: Electricians may use calculus to analyze and solve more complex problems related to electrical systems.
- 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 are the Different Types of Math an Electrician 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.
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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.
Electrician Math 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.
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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 needed for the job
Electrician Math 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.
Electrician Math Example 3: Finding the Length of a Cable (Using Geometry)
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.
Electrician Math Example 4: Finding the Right Cable Size (Advanced)
Electricians also need to know how to calculate the voltage, ampere, resistance, and watts of an electrical circuit. The more advanced math in relation to the trade of an electrician is mostly taught at electrical trade school, in order for you to gain knowledge of what goes on behind the scenes in electrical installations.
Here you will learn the fundamental of electrical systems. This involves an understanding and an introduction to how to calculate the relation between a volt, ampere, and ohm (also called Ohms Law).
Math Example: Suppose an electrician needs to install a new electrical circuit in a home. The circuit will be used to power a number of appliances, including a washing machine, a dryer, and a water heater. The electrician decides to divide the circuit into two groups, with the washing machine and dryer in one group and the water heater in the other. The electrician knows that the washing machine and dryer have a combined wattage of 5,000 watts, and the water heater has a wattage of 4,500 watts.
In order to determine the appropriate size of the electrical cables, the electrician needs to first calculate the total wattage of each group by adding up the wattages of the appliances in each group:
Group 1: 5,000 watts Group 2: 4,500 watts
Next, the electrician needs to determine the current (in amperes) that will be flowing through each group. The formula for calculating electrical current is:
I = P / V
- I is the electrical current in amperes
- P is the power (in watts)
- V is the voltage (in volts)
In this case, the electrician knows that the circuit will be powered by a 240-volt outlet, so they can plug that value into the formula for each group:
Group 1: I = 5,000 watts / 240 volts = 20.83 amperes Group 2: I = 4,500 watts / 240 volts = 18.75 amperes
Next, the electrician needs to determine the appropriate size of the electrical cables for each group based on the current and the length of the cables. The National Electrical Code (NEC) provides guidelines for selecting the appropriate size of electrical cable based on the current and the length of the cable.
For example, the NEC might specify that a 14-gauge cable can safely carry a current of up to 15 amperes for a distance of up to 15 feet, while a 12-gauge cable can safely carry a current of up to 20 amperes for a distance of up to 25 feet.
In this case, the electrician knows that the cables in Group 1 will be carrying a current of 20.83 amperes, and the cables in Group 2 will be carrying a current of 18.75 amperes. The electrician also knows that the cables will need to be long enough to reach all the appliances in each group.
Based on the NEC guidelines, the electrician might determine that a 12-gauge cable would be the appropriate size for Group 1, and a 14-gauge cable would be the appropriate size for Group 2.
Math Theory of the Electrical Trade (My Final Notes)
If you are someone who is strongly considering a career as an electrician but have 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.