To determine the appropriate welding lead size, consider the welding process, amperage, and lead length. Use the American Wire Gauge (AWG) chart as a reference. Higher amperage and longer lead lengths require larger diameter cables (lower AWG number) to minimize voltage drop, resistance, and cable overheating.
For a hobby welder using less than 240 amps and less than 50 ft in combined cable length, a 1 gauge welding lead is sufficient. If you exceed these constraints or are doing more advanced welding, read through this guide to find a welding cable size that suits your needs.
A welding lead or cable is an all-important part of your welding setup. It is the object that connects your welding machine to your electrode, making sure that you actually have the power you need to weld. Without your welding leads, you would try turning on your welder, and only dust would come out, not a spark.
Choosing the right size welding leads is important for your safety and the effectiveness of the machine you are working with. A few factors influence the size of welding leads you need, including amperage, duty cycle, and other things. When in doubt, consult a sizing chart.
Here is your guide to choosing the right welding leads for your set-up.
Table of Contents
What Is a Welding Cable?
Before we talk about the size of the welding cable you need, we should probably establish what a welding cable is in the first place.
Welding cables and leads are the same things. They are important parts of your arc welding setup. Welding leads are copper wires that connect the arc welding machine with your electrodes. They deliver the electrical power from your machine to the electrode, starting the arc.
Welding cables are specially designed to handle large quantities of electricity. Almost all of them contain copper, one of the best electrical conductors. However, different sizes of welding cables are designed for different electrical capacities. Get a too small cable that might burn or cause an incident when you try to surge a high amperage through it. That’s why choosing the right size welding cable is important.
Types of Welding Cables
There are a few types of welding cables you will encounter when you head to the shop to pick some out. You can distinguish them according to a few of the following factors.
1. Core Material
The core of a welding cable is a strand of hundreds of thin wires that are very flexible and conduct electricity. Most welding cables use a copper core because this metal is the best conductor of electricity. Some use aluminum because it is lighter and more affordable, but the diameter has to be larger to fit more strands of wire.
2. Insulation Material
Welding cables also differ in terms of the material used to insulate them. EPDM and neoprene are two types of synthetic rubbers that are popular insulators because they are very flexible. PVC is less flexible but tougher and less likely to tear even when exposed to rough environments.
3. Purpose
Finally, the welding cables you see in stores differ depending on their purposes. Most are designed to connect the arc welding machine with the electrodes. However, some welding cables are actually grounding cables designed to prevent electric shock. Make sure you get the right type of welding cable for your purpose.
AWG Welding Sizes
AWG or American Wire Guide describes the size of welding cables. You will often see welding cable sizes in terms of their AWG Guage, which has the following specifications:
| AWG Gauge | Max Current | Nominal Diameter (in) | Conductor Diameter (in) |
| 6 | 115 Amps | 0.303 | 0.200 |
| 4 | 150 Amps | 0.331 | 0.228 |
| 2 | 205 Amps | 0.413 | 0.300 |
| 1 | 240 Amps | 0.481 | 0.343 |
| 1/0 | 285 Amps | 0.526 | 0.373 |
| 2/0 | 325 Amps | 0.564 | 0.426 |
| 3/0 | 380 Amps | 0.621 | 0.465 |
| 4/0 | 440 Amps | 0.686 | 0.560 |
Welding Cable Size Chart
This table shows the recommended welding cable size in AWG for different lengths (electrode and work cable combined) for different current draws:
| Amperage | 0 to 50 ft | 50 to 100 ft | 100 to 150 ft | 150 to 200 ft |
| 125 | 6 | 5 | 3 | 2 |
| 150 | 6 | 5 | 3 | 2 |
| 175 | 4 | 4 | 3 | 2 |
| 200 | 4 | 4 | 2 | 1 |
| 225 | 3 | 3 | 2 | 1 |
| 250 | 3 | 3 | 2 | 1 |
| 275 | 1 | 1 | 1 | 1 |
| 300 | 1 | 1 | 1 | 1/0 |
| 350 | 1/0 | 1/0 | 2/0 | 2/0 |
| 400 | 2/0 | 2/0 | 2/0 | 3/0 |
What Size Welding Leads Do I Need for a Duty Cycle Welder?
Every single welding machine has a duty cycle. The duty cycle describes how long the welding machine can be operational in 10 minutes without overheating. The duty cycle changes with a few factors, including the amperage of the welding machine.
As a rule of thumb, the longer the duty cycle, the thicker welding leads you will need. If the duty cycle is longer, more power will be coursing through the welding cable. You need a welding cable that will stand up to that consistent amperage.
For a higher duty cycle (this will depend on your machine and the type of welding you are doing), choose a thicker welding lead, such as 2/0 or 3/0 cable size.
What Size Welding Leads Do I Need for an Amperage Welder?
Every welding machine also has its own amperage. The amperage of the welder machine describes how much current flows through the circuit. Most welders can adjust amperages along a range.
If you know that you will be working on projects along the higher end of the range of your welder’s amperage, you need to get bigger welding leads with a higher ampacity. The ampacity is the current that a cable can carry without causing damage.
The biggest potential damage comes from the heat that electricity generates. If your cable has a low ampacity, the electrical current will burn through the cable. At best, you will need to stop work and replace your cables. At worst, you will cause a workshop fire.
Calculating ampacity on your own is difficult because you have to look at the size, circuit length, and other factors. That is why you should look at the cable size chart. These charts tell you which cable you should get based on the maximum amperage and duty cycle. They are very useful tools to have when you’re buying welding cables.
What Length Welding Leads Do I Need?
Your welding leads should be long enough to reach your workspace from the welding machine. I recommend selecting at least 15 feet of welding lead length to give yourself plenty of room to maneuver.
However, the length of the welding leads also impacts the current capacity.
When choosing your welding cables, look at the length of the welding setup, from your grounding cable to the electrode holder. Then, look at the chart to see the cable size you will need. Choose the length of the welding leads that will fit within the range recommended for your cable size.
For example, if you are operating at a 20% duty cycle and want to use a size eight cable, you must ensure the setup is below 50 feet. You will need a shorter welding lead than if you go a size up and choose a size four welding cable.
Final Thoughts
Choosing the right size welding cables is important because you don’t want your machine to work improperly or catch fire. Luckily, a standardized size chart using American wire gauge sizing tells you which size to get according to duty cycle, amperage, and length.
