When you work on an electrical project, you want everything to perform smoothly in a safe environment. Choosing the right wire gauge is one of the most important factors in running electrical devices well.
Once you understand the power consumption of an electrical device, it helps you get a better idea of what the wire size should be. If you’re confused about choosing the correct wire gauge, don’t worry! We have discussed it in detail in the following article, so keep reading!
Understanding the Basics of Electricity
To start, it's very important for you to know these three main electrical terms:
- Watts: This measures the amount of power that your device uses. Essentially, it tells you how much energy the device consumes to operate.
- Amps: This measures the flow of electricity, or how much electrical current is moving through a wire.
- Voltage: This is the force or pressure that pushes the electrical current through the wire.
You can see how these three things watts, amps, and voltage work together to run any electrical device. If you want to know how many amps a device uses, you can convert watts to amps by using this simple formula:
- Amps = Watts / Volts
This step answers why do we need to convert watts to amps? It also helps you know the exact load that passes through the circuit and decide if the wire can carry that current safely or not.
Step-by-Step Process for Choosing the Right Wire Gauge
You can follow these simple steps to choose the correct gauge:
Measure the Power
First of all, you need to check the wattage of the device. The wattage is usually listed on the label of the device or on its user manual.
Convert Watts to Amps
Then convert the watts to amps with the help watts to amps formula that we discussed above. You can also use watts to amps calculator to get a quick and accurate current value.
Consult the Wire Size Chart
You can also check on an electrical wire size chart to find out which gauge supports the calculated amps. We have given this chart below, so you can also consider it.
Consider the Circuit Conditions
You also need to consider the length of the wire because the longer the wire, the more resistance it has, which could affect the performance of your device. The second thing you need to decide is where the wire will be placed.
For example, will it be inside a wall, outside exposed to the weather, or in a damp area like a basement? Different environments can affect how much wear and tear the wire will experience. This also helps you decide the type of wire you should use.
Follow Safety Codes
It's very important to check your local electrical safety codes and standards before you start installing any wiring. These codes are rules created by experts to make sure electrical systems are safe for everyone.
Once you follow all these steps, you can easily decide the accurate wire gauge for your project. It also prevents the wire from being overheated or safety threats.
Using the Watts to Amps Calculator
A watts to amps calculator is an online tool that makes the whole watt to amp calculation very easy. Simply open the tool, enter the wattage and voltage value into its given fields and that’s it. The calculator then convert watts to amps in a few seconds and the results show right on your screen. Using the online tool is a very convenient option as it prevents you from doing manual calculations.
Electrical Wire Size Chart
An electrical wire size chart tells you how many amps each wire gauge supports. To help you with this, we have provided a chart below. Where you can see the ratings for different gauges and choose one that perfectly matches your needs.
Wire Gauge | Amps Supported | Common Applications |
14 gauge | 15 amps | Lighting and small outlets |
12 gauge | 20 amps | General circuits and standard outlets |
10 gauge | 30 amps | Heavy appliances like air conditioners and motors (10 gauge wire amps) |
8 gauge | 40–50 amps | Sub-panels and high-power equipment |
6 gauge | 55–65 amps | Large appliances like ovens and big air conditioners |
Note: You have checked this chart now you can select a wire that safely carries the calculated current. For example, if your calculation shows 10 amps, you choose a wire gauge that supports more than 10 amps, such as 14 gauge or 12 gauge, based on the application and distance of the circuit.
A Practical Example
Let’s say you have an electric device that uses 1200 watts at 120 volts. So you can calculate its amp uses with the watts to amps formula:
- Amps = Watts / Voltage
Step 1: Now, add values to this equation:
- Amps = 1200 / 120
- Amps = 10 amps
💡 You can also use amps to watts calculator for instant and correct results.
Step 2: Compare the result with the electrical wire size chart:
As you can see in the previous wire size chart, the 14 gauge wire can support up to 15 amps of current. This means an electrical device that needs 10 amp of current to run, must have at least 14 gauge of wire.
Note: But here is another factor that you have to consider which is the length of the wire and the environment where it would be installed. So to be on the safe side, you can use 12 gauge wire for extra safety.
Let’s Wrap Up Things!
In this article, we have shown how to choose the right wire gauge by using watts and amps calculations. You can also use a watts to amps calculator to convert watts to amps. We have also included an electrical wire size chart so that you can easily match the correct gauge to the calculated current. By following this simple guide, we hope you can easily choose the right wire gauge for your project.
