What Does Extension Cord Gauge Mean? (Does It Matter?)

Extension cords are necessary for any number of household jobs.

In addition to being useful, extension cords can be dangerous if not used properly.

The most important thing to remember when using an extension cord is that it must have enough power for whatever device you’re using it with. If it doesn’t have enough power, or if it’s too thin, then it could overheat or even catch on fire.

In this article, we will look at what an extension cord gauge means and whether or not it really matters.

Here’s What Extension Cord Gauge Means:

The gauge number of an extension cord refers to the thickness of the wire inside of it. The lower the number, the thicker and heavier the wire will be. So, a smaller gauge number means a thicker wire, which makes for a more durable extension cord. And the higher the number, the thinner the wire is.

Extension long wound on a big tree stands at the apartment walls, where there is a face-lift. The plug is inserted into the socket.

What Are the Different Types of Extension Cord Gauge?

There are three main types of extension cords: indoor use, outdoor use and heavy duty (or “expert”) use. Each type has different requirements that dictate what type of extension cord gauge you should choose:

  • Indoor use, which is 16-gauge. This type of cord is designed to be used inside the home and comes in a variety of lengths. It can be used with indoor appliances such as lamps, TV sets, computers, laptops and printers.
  • Outdoor use, which is 14-gauge. This type of extension cord is designed for outdoor use only and should never be used inside your home or garage. The thicker insulation protects against damage from extreme temperatures such as those experienced during the winter or summer months. Outdoor cords come in lengths ranging from 25 feet to 100 feet long so you’ll have plenty of room to work with when using them at events like parties or picnics where there may not be an electrical outlet nearby.
  • Heavy duty indoor/outdoor use, which is 12-gauge. This type of extension cord combines the best features of both indoor and outdoor cords into one product that can be used indoors as well as outdoors without any damage to the cord itself because it has the thick insulation necessary for outdoor use but also has multiple outlets so it can easily be used inside your home as well.

Are 12 Gauge or 14 Gauge Extension Cords Better?

A higher gauge number means that the wire is thicker and can carry more current. The lower the gauge number, the thinner and less capable it is at carrying current.

A 12-gauge extension cord can carry up to 15 amps of current while a 14-gauge extension cord can only carry up to 13 amps of current. So why have both?

If you’re using a 12-gauge extension cord for indoor use with small appliances like lamps or refrigerators, the thicker wire will allow you to use those devices without worrying about tripping over or unplugging them because they’re connected to an outlet too far away from where they’re used.

However, if you’re planning on using an outdoor appliance such as an air compressor or leaf blower where there’s going to be some serious voltage running through your cord, then it may be safer to opt for a 14-gauge extension cord instead so that it won’t burn in case something goes wrong with your appliance’s motor.

Check this blog out about can you leave an extension cord outside?

Gauge Size and Ampacity

The ampacity of a wire is determined by its gauge. Larger wires can handle more current than smaller ones because they have more surface area to dissipate heat as electricity flows through them.

This means that you should use larger gauge wires if you need more power or want to run multiple appliances off one outlet strip or extension cord.

For example, if you need to run several appliances that draw 10 amps each while maintaining safety standards, then you should use an extension cord with at least a 12-gauge rating with 2 prong outlets spaced 4 inches apart on the outlet strip or power bar (according to UL standard).

What Gauge Is a Standard Extension Cord?

A standard extension cord is typically marked with a gauge rating, which refers to the thickness of the wire.

The National Electrical Code (NEC) requires that cords for appliances, for example, have a minimum gauge rating of 16.

When shopping for cords, avoid buying anything less than 14 gauge because it won’t be able to handle much current and may overheat and melt.

The cable’s length also affects how much current you can draw from it. The longer it is, the more resistance there will be in the cables and wires themselves. As a result, you won’t be able to draw as much current from a long cord as you can from a short one of equal size and gauge rating.

How Do I Know What Gauge My Extension Cord Is?

When you’re out shopping for an extension cord, it’s easy to get confused by the many different types of extension cord gauge. However, there are just three main types of gauge: AWG (American Wire Gauge), mm2 (millimeter squared), and SWG (standard wire gauge).

AWG is used in North America and Canada while mm2 is used in Europe and Australia. In both cases, the smaller the number, the thicker the wire. For example, 14 AWG is thicker than 16 AWG, which means that it can handle more current at the same voltage.

In general, you should use a heavy-duty extension cord with a higher gauge when you need more power or if you’re working with tools that require more electricity.

For example, if you have a high-powered tool like a circular saw or handheld grinder/sander that uses 120 volts of electricity and draws a lot of power from an outlet, then you should use a heavy-duty extension cord with a lower gauge number such as 12 or 14.

How Do I Know What Gauge Extension Cable to Use?

If your device draws less than 6 amps (amps = amperes), then you can use any gauge extension cord up to 15 amps as long as it is rated for outdoor use (which most are).

If your device draws more than 6 amps but less than 25 amps, then you should use a 12 gauge extension cord rated at 30 amps or higher.

If your device draws more than 25 amps, then you should get an 8 gauge extension cord rated at 50 amps or higher.

You should also keep in mind that higher gauge numbers mean fewer watts per foot of cable. So if you’re using multiple extension cords together to run power to one appliance or device, you may need to get longer cords with lower gauges in order to keep them under 100 watts per foot of cable length.

Does Gauge Really Matter for Extension Cables?

When it comes to extension cords, you might think that a thick cable would be better because it has more electrical resistance and therefore less voltage drop over distance.

However, this is not correct. In fact, the opposite is true: A thinner cable results in less voltage drop over distance than a thicker one.

This may seem counterintuitive at first glance, but if we look at it from an electrical engineering perspective, it makes perfect sense. A wire’s resistance depends on two factors: its length and its cross-sectional area (i.e., its diameter). The longer a wire becomes, the more resistance it offers; conversely, if you make it shorter but keep its other dimensions constant (e.g., by increasing its diameter), then its resistance decreases without changing anything else about it.

Here’s why gauge matters:

  • Thicker wires are more durable and can handle more power than thinner ones. For example, if you were using a 20-gauge extension cord to power a high-powered appliance like an electric lawnmower or snow blower, it would burn through very quickly because it just isn’t strong enough to handle that much power without overheating.
  • Thicker wires conduct electricity better than thin ones do because they have more surface area for electrons to travel across (which means less resistance). This means that thick wires can transfer power over longer distances with less loss of voltage or amperage than thin ones can.


When it comes to deciding which extension cord you’ll use, there are a few things to consider: what’s being plugged in, how much power it uses and how far away the outlet is.

But one thing that might not be as obvious is gauge — or the thickness of the wires inside your extension cord.

We hope that after this blog you understand what extension cord gauge means.

Read this blog about 13 things you should not plug into an extension cord.


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