When it comes to electrical wiring, numbers such as 14/2 or 12/2 hold the key to understanding the capabilities of these wires. These are seemingly mysterious combinations for many, but when you know, you will have a clear picture of their suitability for various applications.
In this article, we’ll break down the differences of 14/2 vs 12/2 wires and help you make informed decisions when it comes to powering your home. Whether you’re a DIY enthusiast or simply curious about how electrical systems work, this article is designed to cover almost everything that you need to know.
What is 14/2 and 12/2 Wire?
14/2 and 12/2 wires are simply electrical cables used to carry electric power within an electrical system. Inside each electrical cable are two wires, also known as conductors. The first number of each wire indicates the wire gauge, which gives us an idea about its thickness. The second number indicates the number of conductors in the cable.
So, for a 14/2 cable, the wire gauge is 14 and contains two wires. Similarly, the 12/2 cable also has two wires, with a wire gauge of 12.
As mentioned earlier, the wire gauge, represented by the first number, indicates the thickness or diameter of the wire. Interestingly, although it might sound a bit odd, the lower the first number, the thicker the wire. Therefore, 12/2 wires are more thicker than 14/2 wires.
A wire with a lower gauge is wider and has a larger cross-sectional area. This characteristic results in lower resistance when current flows through it. Consequently, a thicker wire can effectively manage higher currents without generating excessive resistance and heat.
Because the 12/2 wire is thicker and more substantial than the 14/2 wire, it’s capable of safely carrying larger amounts of electric power.
Now, let’s look at some of their differences so they become clearer to you.
Difference Between 14/2 and 12/2 wire
Based on some features and parameters, we can better understand the key distinctions between 14/2 and 12/2 wires.
Thickness and Diameter
The diameter of 12/2 wires falls roughly in the 2.05 to 2.5 millimeters range. On the flip side, the diameter of 14/2 can be approximately between 1.63 to 2.05 millimeters. Keep in mind that these measurements are just approximations, and the actual value may also be influenced by factors such as manufacturers, insulation thickness, wire material, and manufacturing processes. However, we can confidently state that 12/2 wires are indeed thicker than 14/2 wires due to their lower wire gauge.
The ampacity of wire or cable is simply the maximum current-carrying capacity of the cable safely without exceeding its temperature limit. It significantly depends on the wire’s thickness, also called the wire gauge.
The typical unit for measuring ampacity is amperes (amps). Ampere denotes how much electrical current is flowing through a wire or circuit. The higher the number of amps, the more electric charge passes through.
Due to its thicker nature, the 12/2 wire can safely handle approximately 20 amps of current. On the other hand, the 14/2 wire, being comparatively thinner, can accommodate a maximum of 15 amps of current without facing the risk of overheating and damage.
Generally, 12-gauge wire (12/2) has less resistance than 14-gauge wire (14/2) due to its larger cross-sectional area. This lower resistance means that 12-gauge wire can carry more current while experiencing less heating and voltage drop compared to 14-gauge wire.
12/2 wires, being thicker, can be used to power a wider range of devices throughout your home, including those that require more electricity, such as refrigerators, dishwashers, ovens, microwaves, air compressors, air conditioners, etc.
On the other hand, 14/2 wires, being slightly thinner and having lower current-carrying capacity, can only be used to power those devices that need lower electricity, such as ceiling lights, wall sconces, landscape lighting, toasters, coffee makers, blenders, etc. It’s commonly used for lighting fixtures and other smaller electronics.
Both 12/2 and 14/2 wires have more or less a similar strength as they are both commonly made of copper or aluminum and maintain the same tension. Yet, when it comes to durability, the 12/2 wires have a slight advantage over the 14/2 wires. Due to the 12/2 wire’s greater thickness, these can be used outdoors and are designed to withstand severe environmental conditions like moisture and UV exposure.
Loss or Voltage Drop
The key factor responsible for increased voltage drop is resistance. As we already know, thicker wires lead to lower resistance. Accordingly, a 12/2 wire is supposed to have lower resistance than a 14/2 wire. Therefore, it causes less amount of voltage to drop while carrying a large amount of current over a long distance or under heavy loads. When the voltage drop is high, the devices or outlets do not receive the voltage they require to function properly.
Wire Gauge and Breaker Compatibility
The ampacity of the wire gauge and breaker should be the same. For example, 12/2 wires normally have a maximum current carrying capacity of 20 amp, which makes them only suitable for circuits with 20 amp breakers. That said, connecting 12/2 wire with 15 amp circuit breakers is not recommended, which can lead to overheating and damage.
The same is true for 14/2 cable. Its 15 amp wire capacity is exclusively compatible with 15 amp circuit breakers.
Wire Gauge and Receptable Compatibility
According to the USA National Electrical Code, a 20-amp circuit with 20 gauge wire is compatible with 15-amp receptacles. However, in this case, you can’t use the quick-connect feature, which is normally designed for 14-gauge wire. Instead, you must use the screw terminals on the receptacles for a secure connection. Additionally, it is important to ensure that the switch on the receptacle is rated for the amperage of the load served and the voltage of the circuit.
However, the reverse is not possible. In other words, a 15-amp circuit with a 14-gauge wire is not compatible with 20-amp receptacles. These receptacles are designed for circuits capable of handling currents up to 20 amps, which the 15-amp circuit with 14-gauge wire cannot provide.
Number of Lights (Approximation)
The number of lights that can be connected to either 14/2 or 12/2 wire relies on the power consumption of each light. Assuming each light uses 60 watts and the standard residential voltage is 120 volts, let’s perform the calculations:
For each light, the electricity usage is (60 watts / 120 volts) = 0.5 amps, calculated using the P=VI formula.
With 0.5 amps per light, a 20-amp capacity (the maximum for 12/2 wires) can support 20 / 0.5 = 10 lights.
Similarly, applying the same assumptions and calculations, a 14/2 wire can handle around 7.5 or 7 lights.
It’s important to note that this calculation assumes all lights are operating simultaneously. If the lights won’t all be on together, you might be able to connect more lights. Also, consider the power requirements of other devices connected to the circuit when assessing the total load on the wire.
Which one should You use: 14 AWG or 12 AWG?
While many people might suggest you use 12 AWG wire as it can handle both lower and higher electrical demands. However, using 12/2 wire for all devices might not always be the most efficient or cost-effective choice.
You’ll likely incur unnecessary expenses if you decide to install all electrical outlets using 12-gauge wire, 20 amp breakers, and 20 amp outlets. That’s why we recommend using 14 AWG for connecting lighting fixtures, lamps, and smaller electronic devices.
On the other hand, for outlets to power devices with higher amperage requirements, such as kitchen appliances, power tools, and larger electronics, you must use 12 AWG.
Keep in mind that having to rewire a circuit for 20 amps can be way more expensive. Considering the potential high cost and convenience, if you want to future-proof your wiring and get long-term benefits, using a 12/2 wire could be a fantastic idea.
Navigating the world of electrical wiring might have seemed like a complex puzzle, but now you possess the key to deciphering the differences between 14/2 and 12/2 wires. These numbers hold the answers to wire gauge, ampacity, and how they influence the devices and appliances you power.
Understanding the advantages of each wire gauge and its respective applications enables you to make informed choices that balance efficiency, safety, and practicality. We hope you’re ready to confidently tackle your electrical projects and make well-informed decisions with this knowledge.