Do you have a welder in your home? Can you afford to connect it to any random circuit? No, you can’t. Welders are powerful tools that could easily burn your house down. You need a fitting circuit breaker with the correct wire gauge. But what is the proper wire size for a welder? This guide will tell you.
What Size Wire Do I Need For A Welder?
You need 6-8 gauge wire for a welder. You can use 8AWG for a 40A breaker and 6AWG for a 50A breaker. These wire sizes can run a 225A model which is the industry standard.
Homeowners choose to buy smaller models because they don’t need powerful welders to use in workshops. They prioritize the same 50A 240V circuits that can run a 225A welder. These are the same circuits that run on 6 or 8AWG conductors.
The idea is to create a system that can operate a larger welder. This allows you to upgrade your welder down the line without changing the wiring. In other words, you have to wire your home with the future in mind.
If you wire your circuit to fit a smaller model, what happens when the need for a larger model arises? Don’t forget: you can’t just change the circuit breaker. Each breaker size has a corresponding wire size.
A small breaker isn’t dangerous. It is a nuisance. The breaker will continuously trip because it can’t handle the electrical demands of a larger welder. It does this to keep the wires from melting.
If you change the breaker without upgrading the wires, they will melt because they can’t rely on the breaker to protect them. You can avoid this headache by getting a larger circuit breaker.
How To Determine The Correct Wire Size For Welders?
Welders are just like any other appliance. They are not quite as complicated as people think. When it comes to finding the correct wire size, you have several avenues, including:
1). Use 6-8 Gauge Wiring For Industry Standard Welder
You can just use the industry standard. The average welder can run on 6 or 8-gauge wiring. People recommend this size for a reason. Don’t use these sizes if you have a larger, more powerful welder. You can use other steps to identify the correct wire size for a heavy-duty tool.
But if you have one of the smaller models, 6 and 8-gauge cables are perfectly adequate.
2). Check The NEC Table
Have you ever stopped to wonder why people recommend 6 and 8AWG cables? They use the amp ratings. Every amp rating has a corresponding wire size. How do you calculate the wire size of a given amp rating?
You don’t have to. Just look at NEC Table 310-16. It shows all the amp ratings and their wire sizes. Consider the table below. You can see that 8AWG can transmit 40 amp at 60 degrees C.
| 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 NM-B, UF-B | 75˚C THW, THWN, SE, USE, XHHW | 90˚C XHHW-2, THHN, THWN-2 |
| 14 | 20 | 20 | 25 | – | – | – |
| 12 | 25 | 25 | 30 | 20 | 20 | 25 |
| 10 | 30 | 30 | 30 | 25 | 25 | 25 |
| 8 | 40 | 50 | 55 | 30 | 40 | 45 |
| 6 | 55 | 65 | 75 | 40 | 50 | 60 |
| 4 | 70 | 85 | 95 | 55 | 65 | 75 |
| 3 | 85 | 100 | 110 | 65 | 75 | 85 |
| 2 | 95 | 115 | 130 | 75 | 90 | 100 |
| 1 | 110 | 130 | 150 | 85 | 100 | 115 |
You can also see that the amp rating increases with the temperature rating. Conductors with higher temperature ratings can transmit more electricity. The table includes the amp ratings of different types of wires.
6AWG works with 55 – 75 amps. Why do professionals recommend 6 and 8AWG? Because they expect the amp ratings of modern welders to range between 40 and 60 amps.
The recommendations are not random guesses. They took the amperage of the welder into account. You should do the same. Find the welder’s amp rating and use the NEC table to find the corresponding gauge.
This is the safest method because it allows the consumer to match the welder’s electrical demands to the best possible gauge.
3). Circuit Breaker Must Exceeds The Welder’s Amperage
The circuit breaker size is more important than the welder’s amp rating. If you ask a professional to install a breaker capable of accommodating the welder, you need a gauge that matches the breaker’s amp rating.
Electricians select the breaker size by calculating the total amperage of all your equipment. If you have a dedicated circuit for the welder, the electrician probably installed a bigger breaker than the amperage of the welder just to be on the safe side.
If you haven’t installed the breaker, get a breaker size that exceeds the welder’s amperage. Otherwise, the welder will repeatedly trip the breaker.
4). Check The Manual
You can use a 60A breaker for the Lincoln 225 ARC welder. From the above NEC 310-16 table, you can see that 60 amps require 6 to 4AWG depending on the temperature rating.
Try searching for similar information about your welder on the internet. Someone will tell you the correct wire gauge to use. Obviously, you can’t use one source. Check several sources. If they all match, you can proceed.
A better option is to look at the manual. The manufacturer won’t take any chances. They will tell you the exact amperage and wire size to use. Therefore, the question of wire size shouldn’t concern you.
Does Voltage Matter For Welder?
The voltage setting affects the arc length. If your primary concern is the wire size, you can still use 6 or 8AWG. These cables can work for both 220V and 115V welders.
The amps are the biggest concern. The wire size will change with the amperage, not the voltage.
| VOLTAGE | WIRE SIZE |
| 220V Welder | 6 – 8AWG |
| 230V Welder | 6 – 8AWG |
| 240V Welder | 6 – 8AWG |
Does Distance Matters For Welder Wire Size?
The distance can mean the difference between life and death, especially for consumers that rely on extension cords. People don’t expect extension cords to work with welders. But if you can get an extension cord with the appropriate gauge and rating, it will run your welder without a problem. The distance matters because it affects the voltage drop.
You get a higher voltage drop in long cables. And unfortunately, a high voltage drop limits the power the welder receives. You have to keep the voltage drop below 3 percent by raising the gauge.
Thin wires have higher voltage drops because their resistance is more significant. Increasing the gauge elevates the amount of electricity the conductors can carry. This compensates for the long distance.
It is worth noting that a high voltage drop is not your only concern. Long cables are more likely to overheat because the resistance is much higher. This is why professionals hate extension cords.
People use extension cords when they don’t have wall outlets in the vicinity. Unfortunately, homeowners have a reputation for buying extremely long extension cords just in case they have to cover massive distances. They don’t realize the dangers such lengths pose.
Wire Size VS Amps – Does Amp Matter?
| AMPS | WIRE SIZE |
| 30A Welder | 8AWG |
| 50A Welder | 6AWG |
| 60A Welder | 4AWG |
| 180A Welder | 4/0 |
| 200A Welder | 215kcmil |
| 225A Welder | 300kcmil |
Yes, the amps matter. You have to match the gauge to the amperage of the welder. For instance, you have to use 40 to 50A welders to operate on a 50A breaker with 6AWG wires. On the other hand, 30 or 40A welders can run on a 40A breaker with 8AWG wiring.
You cannot identify the appropriate wire gauge without finding the amps. Most NEC tables that mention amps will also highlight the corresponding gauge. You cannot have one without the other.
The voltage matters, but it doesn’t affect the gauge. If you know the voltage but the amps are missing, you cannot determine the gauge. However, if you know the amps but the voltage is missing, you can still find the wire size.
Factors to Consider Before Using Welder
- Wire Type
What kind of wire do you want to use? Copper is more conductive than aluminum. But aluminum is cheaper. You cannot use 6AWG aluminum to replace 6AWG copper. Because copper is more conductive, you need a thicker aluminum wire to replace copper.
Again, the NEC tables will tell you everything you need to know, including the appropriate wire gauge and amp ratings for each material.
- Breaker Size
The breaker size is vital. If the breaker is too small, it will trip incessantly because it cannot handle the welder’s power. The wires will overheat and melt if you upgrade the breaker size without increasing the gauge.
- Voltage
You have to consider the input voltage before proceeding. In most cases, you only have two options to choose from. Therefore, the decision is not that difficult to make. You need 110V for thin materials and 230V for thick materials.
- GFCI
You have to install a GFCI if you have a welder in places like the garage that requires a GFCI. People expect welders to trip GFCIs, but that is not true. You can pair a GFCI with a welder.
- Extension Cord
If you must use an extension cord, match the extension cord’s gauge to the amp rating of the welder. Keep the extension cord short. Look for heavy-duty 25-foot models with a gauge of 8AWG or thicker.
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