When it comes to choosing a wire gauge for your lights and outlets, there are a few standard models you can choose from, including the 14/2 and 12/2.
The choice will largely depend upon the purpose of the wire, as well as the amount of current it is supposed to carry.
Being familiar with the characteristics and capabilities of the wire gauge will give you the ability to decide what is the best choice for your home, depending on a few important factors.
The main differences between 14/2 and 12/2 are thickness, price, and of course, the amp limitation.
What is a 14/2 wire?
The 14/2 jacketed cable contains 14-gauge electrical wires. There are three types of electrical wires in a 14-gauge combination, each of which has a different role.
The first wire is known as the black “hot” wire, which is the main wire that carries electricity to the light source of the switch from the breaker panel.
The white “hot” wire, which is the second type, is also known as the “neutral” wire. Its main role is managing the unused electricity and sending it back to the breaker panel.
Finally, the third wire in the 14-gauge cable is the green or bare copper ground wire. This wire has a very specific grounding role, and it should never be used as a neutral wire, as it could cause electrical shock and serious injuries.
However, the “2” in the 14/2 wire name stands for the number of wires, which means that the 14/2 is usually missing a ground wire.
The 14/2 electrical wire is the best choice for both lights and outlets connected to 15-amp circuits. That being said, it is the safest, most common choice for low-amperage power light fixtures.
Keep in mind that the 14-gauge wire is not a good choice for high-amperage circuits. For instance, it is not compatible with 20-amp circuits, as this amperage requires at least 12-gauge.
As we’ve mentioned, 14/2 is a common choice for both lights and outlets. Nevertheless, it is more frequently used for lights since 14/2 cannot support high-amperage outlets.
As for the lights, 14/2 is a safe solution for lights connected to 15-amp circuits and most built-in light fixtures.
Not only is 15-amp the limit for 14/2 wires when it comes to the capability, but it is also quite dangerous and above all illegal to use them on 20-amp circuits, which is important to remember when choosing between 14/2 and 12/2.
That being said, the main factor to consider when choosing between 14/2 and 12/2 is safety above everything else.
Running a 14/2 wire on a 20-amp circuit could cause numerous issues. If you’re lucky enough, the breaker will simply flip to stop the wire from overheating, but this will also disrupt the power to the circuit.
Another possibility is that the breaker does not flip, causing the wire to overheat, which can lead to permanent damage and even bigger problems such as an electrical fire.
If you’re unsure of the amperage of your breaker, you can simply check the breaker box controlling the circuit you’re using.
Open your breaker box, and then locate the specific breaker that powers the outlet. Usually, the information about the amperage should be stamped on the breaker handle.
What is a 12/2 wire?
These 12-gauge wires are simply two current-carrying conductors, including the white “hot” wire (also known as the “neutral” wire) and the black “hot” wire.
You’ll notice that the 12/2 wires have a larger diameter than the 14/2 ones, usually by 2.5 mm.
When it comes to voltage limitations, 12/2 wires should not be used with voltages higher than 30 volts.
While they are a very good choice for lighting, it is also recommended to pair them with a 15A circuit breaker for the best results.
The 12-gauge wires are also quite easy to install for your outdoor lighting, underwater lighting, or any other kind of lighting in general, as long as the voltage doesn’t surpass 30 volts.
Another important fact about 12/2 wires that are considered a huge advantage is that they’re adequate for outdoor use and quite durable due to their structure and thickness.
These wires are designed to withstand extreme conditions, including moisture, abrasion, sunlight, and even heat up to 140 degrees F.
Another advantage they offer due to their high-quality, durable design and greater diameter is that they can safely handle more load, significantly lowering the possibility of a circuit overload.
As far as conductivity is concerned, the 12-gauge wires are also considered to be superior to the 14/2 ones, creating a better connection between your lighting fixtures and the service panel.
While it is clear that 12/2 wires offer higher quality and more versatility than the 14/2 ones, it is important to mention that they’re also the more expensive option.
However, it is safe to say that with these durable, high-quality wires, you are getting your money’s worth, especially if you intend on installing them outside, or you simply need wires that could handle higher amperage.
While 14/2 wires should not be used on 20-amp circuits, 12/2 wires are suitable for both 15- and 20-amp circuits.
The 12/2 wire also gives you the option of upgrading both your circuit breaker and the outlets to 20 amps whenever you want, in just a few easy steps.
On the other hand, this transition won’t be as smooth if you’re upgrading your 15-amp circuit to 20-amp while using 14/2 wires, which is another factor to consider when making such an important choice for your household.
Then again, it is possible to use both 14/2 and 12/2 wires in your home, as long as you assign them to the appropriate circuits and create a well-thought-out plan, which is something a professional can help you with.
What are the differences between 14/2 wires and 12/2 wires?
While we’ve already mentioned many of the important differences between these two-wire models, let’s go over the most important ones and highlight the crucial facts you should keep in mind when making your decision.
1. Versatility
This is, without a doubt, an aspect you cannot overlook when choosing the wires for your home, especially if you have many powerful appliances, outlets, and lighting fixtures.
While a 14-gauge wire can only be safely combined with 15-amp circuits, you can use the 12-gauge wires on both 15 and 20-amp circuits without the risk of overheating or causing an electrical fire.
What’s more, a 20-amp circuit can safely power up to ten receptacles on a single circuit, whereas a 15-amp circuit allows only eight.
It is also possible to add an extra outlet for every 20-amp circuit you have, which takes the versatility and convenience of this system to the next level.
As long as you use 12-gauge wiring and run all your household appliances on the 20-amp circuit, there should be enough power for every appliance, including your heavy-duty vacuum, fancy heater, or power tools.
A 15-amp circuit, on the other hand, is known to fail with many of these powerful appliances, often causing havoc in your wiring.
2. Pricing
As you can already guess, higher quality and better durability usually come at a higher price, and a 12/2 wire is no exception.
While 12-gauge wires are a bigger investment, if you take all the factors into consideration, you will realize that this is a wiser choice, especially if you intend on using powerful appliances with your 20-amp circuit.
However, it is important to note that households with simple lighting, 15-amp circuits, and limited powerful appliances rarely require an upgrade from 14/2 wiring.
3. Durability
The 14/2 wiring, being thicker and greater in diameter, also offers greater durability. It is, therefore, more suitable for outdoor installations.
14/2 wires have been found to withstand extreme conditions, including exposure to moisture, heat, and abrasion.
The 12/2 wiring, on the other hand, has a thinner structure, which makes it more susceptible to wear and tear.
4. Building code
According to the building code mandates, all bathroom and kitchen outlets must be connected to a 20-amp circuit.
That being said, you will have to choose the 12/2 wiring, at least for these locations, in order to comply with the building code.
However, as we’ve mentioned, it is completely acceptable to create your own combination of wiring throughout the house, depending on your needs.
5. Electricity conductivity and current loss
As we’ve mentioned in the previous section, the 12/2 wire is known as the better electricity conductor, offering a safer, consistent, and more reliable connection.
What’s more, you’ll rarely experience a current loss between your service panel, lights, and appliances in your household with 12/2, which cannot be said for the 14/2 wiring.
14/2 vs 12/2: Are they the same?
While there is little to no difference when it comes to the installation of these wiring models, and they can even be combined in your household to get the desired structure, they cannot be considered the same for multiple reasons.
The 14-gauge wires cannot provide the same level of versatility, as they can only work with a 15-amp circuit. They’re also not as durable as the 14/2 option. However, they are the more affordable solution.
The 12-gauge wires, on the other hand, are far more durable, and even suitable for outdoor use.
You can combine them with both 15- and 20-amp circuits and connect up to ten receptacles without the risk of overheating, which is a common issue with the 14/2 wiring.
Conclusion
When selecting wiring for your home, consider both purpose and code. While 14/2 wire suffices for lighting and outlets on 15A circuits, 12/2 wire enables heavier 20A loads.
The thicker 12/2 wire resists overheating better over long runs, critical for major appliances. Its durability also suits outdoor installations. Yet for indoor lights and outlets, 14/2 is adequate and economical.
Combining both in a thoughtful plan leverages their strengths while complying with regulations. For example, code requires 20A circuits for kitchen and bath outlets.
Discuss needs with an electrician to choose properly sized wires. Matching wire gauge to expected electrical load makes for a safer, longer-lasting system. Investing in quality materials prevents problems down the road.
FAQ
When to Use 12/2 vs 14/2 wire?
When selecting a wire gauge, match the capacity to the circuit’s needs.
For high-power appliances with intense current draws like refrigerators and microwaves, use thick 12/2 wire rated for 20 amps. Its superior conductivity and durability prevent overheating on those demanding circuits.
Lighting, fans, and outlets rarely need more than 15 amps – for those, economical 14/2 wire suffices. Consider code too – some jurisdictions mandate 12/2 for kitchen and bath outlets.
Though 14/2 is cheaper upfront, 12/2 better handles high loads over long runs, reducing fire risks. Choosing the right wire capacity for the expected electrical load makes for a safer, more efficient system.
Should I use 12/2 or 14/2 for dishwasher?
When wiring for a dishwasher, opt for 12/2 wire instead of 14/2. As a high-demand appliance, dishwashers can draw up to 15 amps of current.
14/2 wire’s 15 amp rating makes it prone to overloading, which can lead to circuit breaker trips, overheated wires, and fire hazards. The 20 amp capacity of 12/2 wire is a much safer match for dishwashers.
Besides avoiding electrical issues, 12/2 wire meets code for kitchen circuits. With its higher ampacity, 12/2 can readily handle the current needs of a dishwasher.
Can you mix 12/2 with 14/2?
Mixing 12/2 and 14/2 wire on the same circuit is possible but not recommended.
The main concern is safety – 14/2 wire has a lower 15 amp capacity compared to the 20 amps supported by 12/2. So using a higher 20 amp breaker with mixed wire gauges risks overheating and overloading the 14/2.
To be safe when mixing, use a 15 amp breaker matched to the 14/2 wire’s limits. However, mixing wire gauges may violate local codes or create confusion down the road.
Overall, it is better to use one consistent wire gauge per circuit. If more capacity is needed, replace 14/2 fully with 12/2 rather than mixing.
How can I tell 12/2 wire vs 14/2?
There are a few easy ways to distinguish 12/2 from 14/2 wire.
First, check the thickness – 12/2 is visibly thicker with a diameter of 2.05mm compared to 14/2’s 1.63mm. You can use calipers or a wire gauge tool for precise measurement.
Also look at the ampacity rating, usually printed on the wire insulation. 12/2 supports 20 amp circuits while 14/2 is only rated for 15 amps.
Finally, the color of the insulation provides a clue – 12/2 often has a yellow sheath and 14/2 a white cover. For definitive confirmation, a dedicated wire gauge tester tool is best.
David Kessler is a CSLB licensed contractor with over 25 years of experience. He is specialized in home building, construction, and electrical works; he also has a keen eye for interior design and, over the years, has collaborated with various architects.
