Master electrician Heath Eastman gives host Kevin O’Connor a lesson on wire sizes. Heath displays different wire sizes, ranging from thin to thick. He explains how each wire type gets its name and gives Kevin some examples of what each wire might be used for.
Wire sizing can be confusing. AWG? Aught? 14/2 vs 14/3? What does it all mean? Master electrician Heath Eastman teaches host Kevin O’Connor what these sizes mean and what wires of different sizes are used for.
American Wire Gauge (AWG)
American Wire Gauge (AWG) is the system used to describe the thickness of wires. The higher the number, the thinner the wire. For example, 18 AWG wire is thinner than 14 AWG, and so on, down to 1 AWG.
Beyond 1 AWG, sizes begin to climb again. The size 1/0 (pronounced “one aught”) is smaller than 2/0, smaller than 3/0, and so on.
Why do Wires Come in Different Sizes?
Wires come in different sizes because they serve different purposes. For example, 18 AWG wire is typically used for thermostats. Thermostats don’t require much voltage or amperage, so thinner wire is sufficient for powering these devices and relaying signals. However, for power outlets in bedrooms and offices, 14 AWG wire is more sufficient, as TVs, alarm clocks, computers, and other devices don’t need a lot of amperages but require significantly more than an 18 AWG can handle.
The more amperage a device requires, the thicker the wire will be.
Number of Conductors
Beyond wire sizes, wires also come with varying numbers of conductors. For example, a 14/2 wire will have 3 wires inside the jacket: 2 conductors and a ground wire, all 14 AWG thick. If it were wiring a three-way switch that requires a 3rd conductor, the user would have to use 14/3 wire, which contains three conductors and one ground.
Wire Sizes and Their Uses
The following are some common wire sizes and their uses:
- 18 AWG: Thermostats, doorbells, and other low-voltage applications
- 14 AWG: 15-amp lighting circuits, bedroom and office outlets
- 12 AWG: 20-amp outlets in kitchens, bathrooms, and other areas with devices that draw more current
- 10 AWG: 30-amp circuits that draw a lot of power like small electric ovens and washing machines
- 8 AWG: Small ovens and air conditioning units
- 6 AWG: Electric ovens and car chargers
- Single conductors like 4 AWG, 2 AWG, and beyond are for larger loads like hot tubs, air conditioning units, and subpanels
- 3/0 AWG: Used for wiring 200 amp residential service
Heath explains the range in electrical wire gauges and how they vary depending on the load needed for
a specific appliance. Electric current has a limited capacity dependent on the size of the wire.
Circuits are available in different voltage loads to provide the exact amount of electricity required for a particular appliance. The larger the wire, the more current it can carry, meaning large wires support heavier
electrical loads and smaller wires support lower loads.
Electrical wire can be found at your local home improvement store.