What Size Wire for 50 Amp Breaker? | Wiring Guideline for You

The suitable wire gauge to use with a 50-amp breaker is a 6-gauge wire according to the American Wire Gauge standard. The 6-gauge copper conductor wire has a maximum current rating of 55 amps, making it ideal for this circuit.

In this article, we’ll delve into everything you need to know about choosing the correct wire size for a 50 Amp circuit.

What Size Wire do I Need for 50 Amp Breaker?

One of the most typical amperages for which we require a gauge, breaker, or wire is 50 amp. It is critical to select the correct conductor when constructing a new circuit or rewiring an existing circuit in your home. To decide which wire sizes are safe and suitable for various current sizes, standards have been established in this ampacity chart below.

Using NEC 80% Rule
You can’t make a 50 amp electric circuit with 50A ampacity wire. You will most likely fry the circuit if you do so. The 80 percent rule is a precautionary measure. You should have at least an extra 20% ampacity on top of the 50A ampacity. To figure out the needed ampacity this method is followed:

Wire Ampacity For 50 Amps = 50A / 0.8 = 62.5A

As a result, you should use a wire rated for 62.5 amps as a 50 amps wire. We don’t have any 62.5A wire right now. We have a 6 AWG wire with a 65A ampacity that is the closest match. It’s important to remember that you may always use a larger wire but never a smaller one. 

You could use 4 AWG wire with an 85A ampacity for 50 amps, but you can’t use 8 AWG wire with a 50A ampacity. In most circumstances, 6 AWG wire is nearly perfect for a 50 amp breaker. You’ll probably have to use a larger 4 AWG wire in case you’re transferring current over a long distance.

Account For Voltage Drop

Even if you’re supplying energy over a great distance, say, 100 feet to a 50 amp sub panel, voltage loss must be considered. A useful rule of thumb for voltage drop is the voltage lowers by 20% for every 100 feet. You’ll need to boost the amps by 20% to get the same wattage at the sub-panel 100 feet distant.

That means you’ll have to use a larger wire because you’ll be dealing with a higher current. For instance, 50 amp wire is commonly 6 AWG. If you need to power an electric item from a distance of 100 feet, you’ll require 20% more amps. You’re looking at 62.5A x 1.2 = 75A instead of 62.5A.

The 6 AWG gauge wire with 65A will not be enough in this scenario. At the very least, 75A is required. The 4 AWG gauge wire is the next wire size that can handle more than 75A. This one can carry 85A and is typically used as a 50 amp wire size for sub-panels located 100 feet distant.

Bonus Tips

The size and type of wire used for the circuit breaker do not depend on the type of circuit breaker. Standard circuit breakers, AFCI circuit breakers, and GFCI circuit breakers will use the same cables.

Factors to Consider When Choosing a 50 Amp Breaker

Choosing the right wire size to pair with your 50 amp breaker is crucial for ensuring the safety and efficiency of your electrical system. You should consider when selecting the appropriate wire size for your 50 amp breaker.

1. Length of Wire

The length of wire you need for your 50 amp breaker is an important starting point. Electrical resistance increases with wire length. Longer wires have higher resistance, which can lead to voltage drops and reduced electrical efficiency. 

When determining the wire length, consider the distance between your 50 amp breaker and the appliance or device it’s supplying power to. Longer runs may require a thicker wire gauge to compensate for increased resistance.

2. Types of Conductors Used in Wire

The type of conductor used in the wire plays a significant role in its performance. Common conductors for electrical wiring include copper and aluminum. Copper is an excellent conductor with low resistance, making it ideal for shorter runs. 

Aluminum, on the other hand, is a lightweight and cost-effective option but has higher resistance than copper. Choosing the right conductor material depends on your specific installation requirements and budget constraints.

3. Ampacity and Current Rating

Ampacity refers to the maximum current-carrying capacity of a wire. When dealing with a 50 amp breaker, it’s crucial to select a wire with an ampacity rating that exceeds 50 amps. 

This ensures that the wire can safely handle the load without overheating. Choosing a wire with a slightly higher ampacity rating is always a good practice to allow for some margin and prevent overheating issues.

4. Wire Gauge

The wire gauge, often referred to as the American Wire Gauge (AWG), indicates the wire’s size and diameter. In the context of a 50 amp breaker, you’ll typically need a wire with a larger AWG number, as smaller AWG numbers represent thicker wires. 

The choice of wire gauge depends on the factors mentioned above, such as wire length, conductor material, ampacity, and voltage drop requirements. It’s essential to consult the National Electrical Code (NEC) or local electrical codes to ensure compliance with safety standards.

Common Mistakes to Avoid in Wire Sizing

When sizing wire for a 50 amp breaker, it’s important to avoid common mistakes that could jeopardize safety and system performance. Here, we highlight two key blunders to stay away from –

Undersizing the Wire

Using undersized wire can lead to excessive heat generation, posing a significant fire hazard. It’s essential to carefully assess the ampacity requirements and opt for a wire size that can safely handle the intended current load.

Oversizing the Wire

While oversized wire doesn’t carry the same risks as undersized wire, it can be needlessly costly. It’s advisable to choose a wire size that meets your electrical needs without unnecessary oversizing, striking a balance between performance and budget efficiency.

Wire Size For 50 Amp at 110-240V

A widespread misunderstanding about 50 amp wire is that various wire diameters are required for different voltages. For example, we don’t require a larger or smaller wire size for 50 amps at 240V than we do for 50 amps at 110V.

We utilize 6 AWG wires for 50 amps in all circumstances except when we need to account for voltage loss. The wire size and amps could now be the same. We don’t get different amps with different voltages, we get different power.

Wire Cost Table for Different Sizes, Voltages, and Lengths

The following table provides estimated cost ranges for both copper and aluminum wires (THHN) at different sizes, voltages, and lengths. 

Wire Size (AWG)	Voltage (V)	Length (ft)	Copper Wire Cost Range (per 100 ft)	Aluminum Wire Cost Range (per 100 ft)
12	120	50	$30 – $50	$20 – $40
10	120	50	$40 – $70	$25 – $50
8	120	50	$60 – $100	$35 – $65
6	120	50	$90 – $150	$50 – $90
4	240	100	$150 – $250	$80 – $120
2	240	100	$250 – $400	$130 – $200
1/0	480	200	$400 – $600	$200 – $300
3/0	480	200	$600 – $900	$300 – $450

Note

Different wire types, insulation materials, and local market conditions can influence costs, so the table serves as a general reference for understanding cost differences between copper and aluminum wires based on wire size, voltage, and length.

8-Gauge Wire For 50 Amp

The conductivity of a copper conductor is altered by temperature. The higher the temperature, the greater the current the wire can tolerate up to a point. At 90 degrees Celsius, an 8-gauge wire can handle a current of 50 amps. However, for normal conditions, it’s not recommended.

The insulation around the conductive core would melt or be compromised at this temperature, which is why the AWG operates at 60 degrees Celsius. The 8-gauge wire can handle 40 amps up to this temperature. In the household electrical wiring context, a restriction of 40 amps on an 8-gauge wire is based on this temperature consideration. 

The melting point of PVC insulation, which is commonly used to insulate residential electrical wiring, is 70 degrees Celsius. For the 8-gauge wire, the melting point of the insulation provides a 10-degree temperature window on the rated current at 60 degrees Celsius.

10-Gauge Wire For 50 Amp

The current load that a bare copper wire can carry differs from that of an insulated copper wire of the same gauge. A 50-amp load can be carried by a 10-gauge bare copper wire, but the resistance in the cable will cause it to overheat. Insulated wires have an issue because of the heat generated by the current. 

The heat melts the insulation, resulting in short circuits and the risk of shock and fire. All electrical wiring used for home purposes must be insulated, according to the NEC. As a result, insulated 10-gauge wire has a maximum current rating of 30 amps.

Safety Tips

Selecting the correct wire size for a 50 Amp breaker is crucial for electrical safety. Ensure that the wire matches local electrical codes and regulations, uses the proper insulation type, is grounded correctly, and is protected by an appropriately sized overcurrent device, such as a 50 Amp breaker. Professional installation and regular inspections are essential and never overload the circuit to prevent overheating and potential fire hazards. Prioritize safety practices to ensure a secure electrical system.

Applications of a 50 Amp Circuit

A 50 amp circuit finds versatile applications in both residential and industrial settings, serving as the power backbone for various high-demand devices and appliances. This robust circuit is commonly employed for – Electric stoves, ovens, electric vehicle charging stations, welding equipment, spa and hot tub installations, heavy machinery, commercial kitchen appliances, and RV hookups, ensuring that these power-hungry systems operate efficiently and safely while meeting their specific energy requirements.

People Also Aske (PAA)

FAQ 1: Can you run 50 amps on 10-gauge wire?

Answer: No, you should not run 50 amps on 10-gauge wire. In most electrical installations, a 10-gauge wire is typically rated for a maximum of 30 amps. To safely accommodate a 50 amp load, you would need to use a larger wire size, typically 6-gauge or 8-gauge wire, depending on factors like the length of the wire run and voltage drop considerations.

FAQ 2: How do you calculate wire size?

Answer: To calculate the appropriate wire size, consider several factors: the maximum current (in this case, 50 amps), the length of the wire run, the type of conductor material (copper or aluminum), voltage drop limitations, and the specific electrical codes and regulations in your area. 

FAQ 3: What size wire do I need for a 50-amp 220-volt circuit?

Answer: For a 50-amp, 220-volt circuit, you would typically need a 6-gauge wire. This wire size can safely handle the current while minimizing voltage drop over a reasonable distance.

FAQ 4: Can 6 or 8 Gauge Wire Handle 50 Amps?

Answer: Yes, both 6-gauge and 8-gauge wires are suitable for handling a 50-amp load. The choice between the two wire sizes depends on factors like the length of the wire run and voltage drop considerations. Longer runs may benefit from the use of 6-gauge wire to minimize voltage drop, while shorter runs could use 8-gauge wire. 

FAQ 5: What size wire for 45 amps?

Answer: For a 45 amp circuit, an 8-gauge copper wire is typically used. This wire size provides an ampacity that safely matches the 45 amp load, ensuring both safety and performance.

Conclusion

The NEC’s regulations and the AWG’s standards are the product of extensive experimentation, considering various parameters. These restrictions are primarily intended to increase the safety of electrical wiring systems in both residential and commercial settings. Using a 6-gauge wire on a circuit with a 50-amp breaker installed is the requirement to keep within code.