What Do Wire Sizes Gauge Indicate?
What do electrical wiring gauge sizes correspond to? If you’ve ever looked at those numbers on your wires and wondered what they meant, this guide is for you. Here’s a quick rundown of the sizes available in residential wiring and how to choose the right size for your projects.
How Are Wires Measured?
All wires in the US and the UK use the system called American Wire Gauge (AWG) to measure the thickness of currency-carrying wires and cables. This measuring system first came into use in 1857. It’s the standard that every wiring and electrical job uses to select the proper wires for every project.
Generally speaking, the smaller the gauge number, the thicker the cable or wire.
The measurement does not include any outer insulation, wrapping or protective cover. It only includes the actual conducting wire itself.
Why Is It Important?
The gauge of the wire tells you how much current can safely pass through it. If you don’t use the right size, you’re at risk of overheating and burning if there’s a short circuit. Using the wrong wires is a fire hazard.
Here are some interesting facts about the AWG:
- The most common sizes of wire gauge include 2-, 6-, 8-, 10-, 12- and 14-gauge wire.
- The term “gauge” is used for wire up to 1 AWG.
- The term “zero” is used for a wire that’s 1/0 AWG and larger.
- A wire that is “true to gauge” meets or exceeds the diameter of the copper for its AWG rating.
- As the number gets smaller, the size of the wire gets larger and the amount of amps it can handle also increases.
Gauge Size and Ampacity
Ampacity is the measure of electrical current that can pass through a wire. In general terms, the lower the gauge size, the higher the ampacity. For example, you can safely use 15 amps in 14-gauge wires, 20 amps in 12-gauge wires and 30 amps in 10-gauge wires.
When you set up an electrical system, the ampacity should match the amps of the circuit breaker or fuse.
Why Circuit Load Matters
When you set up an electrical installation, you need to take into account not just the ampacity but the circuit load.
For safety’s sake, you should always calculate the load at only 80% of the circuit’s protection level. In other words, load a 20-amp circuit at only 16 amps or a 30-amp circuit at 24 amps.
It’s important to leave a small amount of what’s called “running amperage” in your system. This allows the safe startup of appliances in your home that need large amounts of current.
Choosing Stranded or Solid Wire
Besides gauge size, another important element of your wire is whether it’s stranded or solid. If you look at your wires, you can see right away whether it consists of a single, solid strand or a group of several strands clumped together.
Stranded wires are stronger and more flexible. They are a good choice for electrical wiring in cars and heavy-duty machines where they can stand up to constant vibration. Single-strand wires tend to be stiff. They are best in residential construction because they’re less likely to split and fray.
Contact SESCOS for All Your Electrical Wiring Needs
Keep your home and your family safe with electrical wiring that’s installed safely and according to code. Whether you have a big job or a small one, call SESCOS for all your electrical needs.
