The ampacity of 14 AWG copper wire varies depending on the type of insulation and the temperature rating. For 60°C (140°F) rated insulations like NM-B and UF-B, the ampacity is 15 amps. When using 75°C (167°F) rated insulations such as THW, THWN, SE, USE, or XHHW, the ampacity increases to 20 amps. If you have 90°C (194°F) rated insulations like THWN-2, THHN, XHHW-2, or USE-2, the wire can handle up to 25 amps of electrical current.

14 AWG aluminum cables are not commonly used due to issues related to conductivity and creep. Unlike copper, aluminum has lower conductivity, which can lead to increased resistance and heat generation. Also, aluminum wires have a tendency to "creep," slowly deforming under pressure, which can result in loose connections over time. 14 AWG applications often require tight connections, and creep can potentially affect reliability and safety to some extent.

Common Applications of 14 AWG Cables

These cables are mostly used for residential applications and outlet circuits. However, they are also used for lots of other applications. Let’s review them. 

Residential Wiring

• Lighting Circuits. 14 AWG cables are commonly employed in residential lighting circuits to connect light fixtures throughout a home.  Typically, 14 AWG wire is used in circuits that are rated for 120 volts, which is a standard residential voltage in the U.S. In residential lighting circuits, 14 AWG is commonly used for wiring light fixtures, switches, and outlets. It’s often found in rooms like bedrooms, living rooms, and bathrooms where the lighting load is relatively light.
• Outlet Circuits. These cables are often used in outlet circuits to supply power to various electrical devices and appliances in a residence. This cable size is commonly used to wire 15-Amp outlets.
• Switch Wiring. 14 AWG cables connect light switches to lighting fixtures and control other devices on 15-Amp circuits. 
• Small Appliances. 14 AWG cables can power small household appliances such as blenders, toasters, and coffee makers. Their flexibility and capacity make them suitable for safely delivering power to these devices.

Commercial Wiring

• Office Lighting. 14 AWG cables are frequently used for office lighting applications. These cables are sized to accommodate the moderate electrical loads associated with lighting fixtures in office spaces. 
• Appliances. 14 AWG cables can be employed to connect various appliances, such as photocopiers, printers, and kitchen appliances in break rooms or cafeterias. 

General Purpose

• Extension Cords. 14 AWG cables are a common size of extension cords
• Power Tools. 14 AWG cables are typically rated for 15 amps, which can sufficiently power many standard electric power tools, such as drills, sanders, and jigsaws, without overheating or risking electrical issues. 14 AWG is stout enough to handle most typical power tool loads but still remains flexible.
• Speakers. In audio systems, 14 AWG cables are frequently used to connect speakers. They  are used for high-quality sound reproduction in home theaters, music systems, and public address setups.
• Control Circuits. Within control systems and automation applications, 14 AWG cables transmit control signals and power to various components. 

Specialty Applications

• Thermostat Wiring. 14 AWG cables are utilized in thermostat wiring for their capacity to carry low-voltage signals with minimal power loss. Note that most thermostat cables are 18 AWG, however, some models can use 14 AWG.
• Landscape Lighting. 14 AWG cables ensure reliable power delivery even in harsh environmental conditions. This size is commonly used due to its ability to handle an adequate amount of power over moderately long runs without suffering significant voltage drop. Landscape lighting typically employs low-voltage lighting systems (usually 12V or 24V).
• Audio Systems and Interior Lighting in Cars. 14 AWG cables are utilized to connect audio systems and interior lighting components. Robotics. 14 AWG cables are used to power and control various robotic components and systems, such as robotic arms, grippers, and sensor arrays.

Popular Types of 14 AWG Wire

Let’s review some of the most common types of 14 AWG wire. 

• THHN/THWN Wire. THHN/THWN wire is versatile and commonly used for building wiring. It is suitable for both dry and wet locations. It is known for its heat and moisture resistance. This wire is a reliable choice for various electrical applications, from switches and lighting fixtures to heavy machinery, control panels, etc. 
• UF-B Wire (Underground Feeder). UF-B wire is specifically designed for underground applications. Its insulation is resistant to moisture and sunlight. This makes it ideal for outdoor wiring, such as for underground electrical service to outdoor fixtures and outlets.
• NM-B wire, also referred to as non-metallic sheathed cable, is a prevalent choice for residential wiring. This cable comprises multiple conductors enclosed in a non-metallic sheath, making it convenient for installation in walls and ceilings. NM-B wire is commonly utilized for various electrical applications in homes, including powering lighting fixtures, electrical outlets, and switches, due to its ease of handling and installation.
• XHHW Wire. XHHW wire is known for its high-heat and moisture resistance. It is often used in commercial and industrial settings where the wiring is exposed to demanding environmental conditions and high temperatures.
• MTW Wire (Machine Tool Wire). MTW wire is commonly used in machine tools and industrial equipment. Its insulation is oil and heat-resistant. This wire is suitable for machinery and equipment where oils and high temperatures are present.
• Solar Photovoltaic (PV) Wire. PV wire is designed for solar panel installations. It is UV-resistant and can handle the direct sunlight exposure and environmental conditions associated with solar power generation. In this size, it is usually used for residential solar systems, solar-powered water heaters and off-grid cabins.
• Speaker Wire. Speaker wire is used for connecting audio speakers to audio systems. It typically comes in various gauges, with 14 AWG being one of the most common choices. 

• Thermostat Wire. 14 AMP thermostat wire is relatively large for thermostat wiring, which usually requires smaller gauge wires due to the low-voltage and low-current nature of thermostat signals. In this size, it’s mostly used in systems with long cable runs or when powering multiple thermostats from a central control panel. thicker wires can help reduce signal loss and ensure reliable communication between thermostats and equipment.
• SOOW. SOOW is a flexible portable cord that is oil-resistant and suitable for outdoor and industrial applications. It is often used for temporary power distribution, construction sites, and equipment connections. It comes in different sizes, but 14 AWG is one of the most common sizes for portable tools.