Don’t feel bad if you’ve never seen 4AWG wire. People don’t use wires that thick, not in residential settings. Although, it helps to understand what they are and what you can expect from the wire size, just in case you ever need it. This guide will educate you.
How Many Amps Can 4 Gauge Wire Handle?
4AWG copper wire can handle 70A at 60 degrees C, 85A at 75 degrees C, and 95A at 90 degrees C. If you have aluminum (or copper-clad aluminum), it can carry 55A at 60 degrees C, 65A at 75 degrees C, and 75A at 90 degrees C.
4 Gauge Wire Amps Rating
| Copper | Aluminum | |||||
| Wire Gauge Size | 60˚C NM-B, UF-B | 75˚C THW, THWN, SE, USE, XHHW | 90˚C THWN-2, THHN, XHHW-2, USE-2 | 60˚C TW, UF | 75˚C THW, THWN, SE, USE, XHHW | 90˚C XHHW-2, THHN, THWN-2 |
| 4AWG | 70 | 85 | 95 | 55 | 65 | 75 |
Every time you go wire shopping, the retailer will ask you to specify the wire size because it matters. Fortunately, the manufacturer prints the size on the jacket. Therefore, you don’t have to calculate this information.
Many manufacturers use the American Wire Gauge standard because it is the simplest means of identifying the wire size. And because the gauge affects the wire’s ampacity, you must figure out the ampacity before determining whether or not 4AWG is appropriate for you.
The thickest wires have the smallest numbers. High numbers are the opposite. You see them on the thinnest lines, which is counterintuitive because people in other fields typically associate higher numbers with greater thickness.
Therefore, as you might have guessed, 4AWG is exceptionally thick, which is why you rarely see the gauge in residential settings. The objective of using higher gauges is to accommodate heavy-duty appliances.
6AWG can carry as much electricity as 4AWG. However, 6AWG is more likely to overheat in the process. The heat will accumulate because of the resistance in the conductors, and if it goes unchecked, the insulation will melt.
Therefore, if a particular application requires 4AWG, you should use 4AWG. People avoid higher gauges because they are more expensive. But you cannot afford to apply a stingy attitude to electrical wires. The wrong wires will start a fire.
Of course, as was noted above, the suitability of 4AWG will depend mainly on the ampacity. You can use 4AWG with 70A. But that applies to copper conductors at 60 degrees C.
What if you prefer aluminum at 60 degrees C? 4AWG will tolerate 55 amps of electricity, which proves that aluminum is less conductive than copper. But that is not a surprise.
There’s a reason why so many people prefer copper to aluminum. If you raise the temperature rating, the ampacity will change accordingly. 4-gauge copper can withstand 85 amps at 75 degrees C.
Naturally, 4AWG aluminum can accommodate fewer amps at that temperature rating.
Don’t expect every country to use AWG. Some locations measure wire size in mm2.
4AWG wire has a cross-section of 21.2mm2 and a diameter of 10+mm. 4AWG cables make 2.17 turns per inch. Additionally, the gauge has a resistance of 0.1608.
4-Gauge Wire VS Voltage – Does It Affect Amp?
| Voltage | Amps |
| 12 V | 70A |
| 24 V | 70A |
| 120 V | 70A |
| 220 V | 70A |
The voltage doesn’t care about the amperage. You only introduce the voltage in conversations that involve the insulation quality.
You don’t want the insulation to break down because it has to contend with more voltage than it was meant to withstand. Therefore, if the insulation of a 4AWG conductor concerns you, look at the voltage.
But if you want to find the ampacity, the gauge should be your only concern. The gauge is similar to the diameter of a water pipe. The diameter of a pipe affects the amount of water it can carry. In that same sense, the gauge reveals the volume of electricity a conductor can transmit.
4-Gauge Wire VS Material (Aluminum VS Copper) – Does It Affect Amps?
Aluminum stands out because it is cheaper and lighter than copper. But many contractors flock to copper because it has superior conductivity.
Have you looked at the NEC’s tables? They show the ampacities associated with various wire sizes, and they always emphasize the difference in amps between copper and aluminum.
Aluminum conductors will carry fewer amps than copper. This explains the interest copper attracts. The material tends to stand the test of time because it has better tensile strength than aluminum.
This is important because electrical installations are usually rigorous. You have to pull several feet of wire through walls and conduits. And if you have aluminum conductors, they are more likely to break.
If that isn’t enough to win you over, copper’s thermal expansion is lower. Therefore, you don’t have to worry about your copper conductors expanding dramatically in response to heat. At the very least, they won’t expand quite as significantly as aluminum wiring.
In other words, you can trust copper to withstand higher temperatures than aluminum. Some people don’t expect the temperature to affect a material’s ampacity, but it matters.
Technically speaking, the ampacity won’t change. Instead, the temperature will affect the amount of electricity you can confidently force through a conductor. For instance, even though 10AWG can transmit 35 amps, you cannot push 35 amps through a 10-gauge conductor if the temperature is too high.
The wire can still handle those 35 amps. However, if you funnel that much current through the conductor when the ambient temperature is already too high, the wire will overheat at a much faster rate.
Therefore, even though a 4AWG aluminum cable’s ampacity remains unchanged, the temperature may compel you to apply the wiring to devices with lower electrical requirements.
This is where copper wins. It can withstand higher temperatures, especially if you buy a 4AWG cable with a decent temperature rating. Cables with higher temperature ratings can transmit more electricity safely.
But that is not an excuse to buy 4AWG copper wire with a high-temperature rating. Have you noticed that many contractors have chosen to purchase aluminum even though copper is readily available?
4AWG copper wire is too expensive, especially if it has a high rating. In fact, many homeowners have never seen 4-gauge copper wire because it doesn’t serve a purpose in the average home.
You don’t have to waste money on expensive copper wiring when aluminum cabling is available and more than capable of meeting every need you find in the average home.
4-Gauge Wire VS Distance – Does It Affect Amp?
Considering 70A, You can run 4 AWG copper wires for a maximum of 95 feet in a 120V circuit, 191 feet in a 240V circuit, and 383 feet in 480V. This is for a single phase. In a three-phase system, you can run 110 feet in a 120v circuit, 221 feet in a 240v, and 442 feet in a 480v with a voltage drop of 3 percent.
For Copper Wire,
Single Phase
| Voltage | Amp | Voltage Drop | Max Distance |
| 120 | 70 | 3% | 95 ft |
| 240 | 70 | 3% | 191 ft |
| 480 | 70 | 3% | 383 ft |
Three Phase
| Voltage | Max Amp | Voltage Drop | Distance |
| 120 | 70 | 3% | 110 ft |
| 240 | 70 | 3% | 221 ft |
| 480 | 70 | 3% | 442 ft |
You also have to identify its application. A cable that can power your jacuzzi over 10 feet won’t work if you extend the length to 150 feet.
With wire sizes, a lower gauge translates into a thicker wire. A thicker wire will counteract the voltage drop, which shouldn’t exceed 3 percent.
Longer wires have more resistance which, in turn, increases the voltage drop. The voltage drop is nothing to scoff at because it can affect the operations of the connected device.
The connected device can stop working if the voltage drop is too high. You can lower the voltage drop by reducing the distance. Have you looked at the power cords of heavy-duty appliances?
Have you noticed how short they are? That isn’t a coincidence. Manufacturers attach short cables to appliances to reduce the resistance. The cord’s ampacity won’t change.
However, increasing the distance will inevitably reduce the amount of electricity the cord can safely carry. Everything comes down to safety. A cable can take as much electricity as you want.
Your biggest concern is whether or not the conductors can transmit that current without overheating. This is why ampacity is so essential. If you force 4AWG cables to transfer more current than their ampacity permits, they will melt and start a fire.
By identifying the ampacity of a 4-gauge conductor beforehand, you can avoid applications that are more likely to start a fire. Although, 4AWG is so thick that your home is unlikely to overwhelm these conductors.
Use of 4-Gauge Wire
4AWG wire is not common because it can handle 70 amps or more. You don’t need that much electricity in a residential setting. You are more likely to find wires of this nature in industrial environments or large construction projects.
Most washers, dryers, and HVACs can run on 10 or 8-gauge cabling. 4AWG is overkill.
You will see these conductors of this size in watercraft, golf cars, and V trailers.
It is also used as a suitable welding size. But this only goes to show you that 4AWG is extremely thick.
4-Gauge Wire VS Watt – Does It Affect Amp?
The average 4AWG copper cable has an ampacity of 70A. Considering 70A, 12V gives 840W, 120V gives 8400W, 240V gives 16800W and 480V provides 33600W.
| Amp | Voltage | Watt |
| 70A | 12V | 840W |
| 70A | 120V | 8400W |
| 70A | 240V | 16800W |
| 70A | 480V | 33600W |
You get the watts by multiplying the amperage by the voltage. Therefore, increasing the amperage will also increase the wattage. You could also argue that watts and amps are two sides of the same coin.
Many manufacturers use wattage to express the amount of power a device uses. But you can change those watts into amps to get a better idea of the load the device will exert on the circuit.
4 Gauge Wire VS Breaker Size
4-gauge wires can withstand 85 amps. Therefore, you wouldn’t be wrong in pairing the wire with an 85A breaker. Breakers protect wires. As such, you want a breaker that will trip when the electrical draw exceeds 85 amps.
If the breaker allows the current to exceed 85 amps, the 4-gauge cables may overheat and melt. 4AWG is extremely thick, but these wires are not indestructible. Additionally, they are not the thickest conductors on the market.
While this is unlikely to occur in a residential setting, you can overwhelm them if you select a larger breaker.
4 Gauge Thhn Wire Amp
70A – 95A