Breaker size for welder: Complete Guide

Welders are a unique bunch. They take machines that produce heat and sparks and use them to join pieces of metal together. But, just like any other machine, welders need protection from overuse and overheating. That’s where circuit breakers come in.

So it’s extremely important to have a deep and clear idea about the appropriate size of the circuit breaker for the specific welder’s amperage level.

For smooth electricity and no electrical fires during welding, a higher circuit breaker is required to ensure more current input. But it shouldn’t exceed the maximum amperage of a machine. 125% is a sweet spot for breaker size.

I will share some information in this article that will help you understand the circuit breaker size for welders in a broader and deeper context.

What Is A Circuit Breaker

Circuit breakers are commonly used in households and businesses as a way to protect against electrical hazards. A circuit breaker is a safety device that interrupts the flow of electricity in the event of an overload or short circuit.

For welding applications, circuit breakers are an essential piece of equipment. It plays an important role in keeping everyone safe. By breaking the circuit, the circuit breaker prevents the wiring from becoming overheated and potentially starting a fire. It’s a real lifesaver.

Which Circuit Breaker Size Is Perfect For A Specific Welder?

Any device’s wiring must suit its current flow rate, and welders use a lot of currents and require a lot of wire for welding. Which is why welders need a reliable and safe way to connect to the electrical grid. A circuit breaker is an important part of this process. And knowing the right size of circuit breaker for welding is a welder’s job.

There are different types of welding machines and depending on the type of job you’re trying to do, it will change, and so the required circuit breaker size will vary.

Suppose your next welding task is to weld a thick metal sheet.Then you will need a 240V weld volt to do the job. And a 240V welder runs require a minimum of 40-50 amp input and a minimum 50 amp circuit breaker is a must for a stable connection.

Also, if you want to know what size breaker you need for a 220V welder, or any other welder type, you will get it on the table I’ve set up below. For example, the table below indicates that a welder with a 220V welder will need a 40 amp breaker.

However, you also need to pair it with a specific size of wire gauge for safety. The summary is with a specific amount of current and voltage thing as wiring and the circuit breaker will be different.

Here in the below, I am adding a small table for your convenience…

Welder Type	Amp Input	Wire Gauge	Circuit Breaker Size
120V welder	Below 30 amp	12 gauge wire	20-30 amp breaker
220V welder	30-40 amp	8 gauge wire	40 amp breaker
240V welder	40-50 amp	6 gauge wire	50 amp breaker

So for the specific range of welders, you need to buy the appropriate circuit breaker size to reduce the chance of any electrical failure.

How To Calculate The Size Of A Breaker

When you know how to find out the size of a circuit breaker for your welder then the chance of any accident will drop to zero. To ensure the safety of your electrical appliance the last limit of breaker is considered is 125% of the welder electric flow rate.

For example: for a 40 amp welder you will require a breaker size that has tp e 40 x 1.25 = 50 amp.

In case you have no idea of the amperage level of your device still you have got ways to find out the right one for you. Using the power level plus voltage you can do it easily. The following equation will help you:

I = P/V

Here, I means current in ampere, P means Watts and V refers to the voltage

For a 2500 Watt welder which runs at 220V, the breaker size will be I = 11.36 amp. After that, you should multiply the I with 1.25 to find out the breaker size.

So in this case breaker size would be 11.35 x 1.25 = 14.2 amp. Hopefully, now the calculation process is clear for you.

Why Is Using The Right Circuit Breaker Important?

It is very important to remember that you need to select the circuit breaker according to the type of welding machine you are using. Because different power welding machines need a different level of current.

A circuit breaker is undoubtedly one of the crucial parts of any electrical system because it regulates the rate of current in the circuit and all appliances. The main purpose of a circuit breaker is to ensure safety by cutting the current flow in both overloading and shorted circuits.

You just can’t add any circuit breaker for any purpose. If you install an oversize circuit breaker, it increases the risk of forming fire due to overheating. On the opposite, installing an undersized circuit breaker will lead to tripping frequently and ultimately result in fire.

What Is The Right Amp For MIG Welder

The level of the amp will depend on the MIG welder and also the specific types of welding you are going to complete.

In the following, we will have a look at that..

Welding material thickness

It’s simple science when you want to work on thicker material, it would require more power for melting plus welding. So welding metal with ½ ‘’ or more thickness would need a 240V MIG welder. And a 240V welder has an amp input range from 30-40 amp. So you must have a powerful and higher amp size circuit breaker for smooth operation.

While working on ¼ ‘’ metal a 110V MIG welder would be enough and they have an amp input level of 20 -30 amp. In this case, a lower amp circuit breaker will be fully fit for the job.

Welding Jobs Type

Your welding project type plays a crucial role in selecting the MIG welder. If you want to use it for small businesses or want to use it for your own farm then a 240 MIG welder would be a great pick. For this, you would require a high amp circuit breaker.

In case of any home use or any DIY welding project, a 120V welder would be the best choice. You can use a low amp circuit breaker for this task.

However, if you have a plan to go for ultra-efficient and high-end welding, you must need a 3 phase welder. Which need 300-600 amp of power input to run and to smooth electricity run high end 50 amp circuit breaker is a must.

Welding Power

The power scale of the welder would be as per the usage of the welding task.

For example, to carry on heavy-duty industrial level welding you must need a 3 phase commercial welder. Because only a powerful welder can continuously weld for long hours. And those welders’ demand range for amp input is around 300-400 amp.

Besides, for mid-level welding tasks like welding in machine shops and small welding shop a 240V welder would give you an ample amount of support. And this level welder requires an amp input of 30-40 amp.

If you want to do welding for any home stuff then a low power welder would be okay and a 20-30 amp input would be suitable for the job.

Duty Cycle

Duty cycle of the welder means the proportion of operation plus the cooling period. This ratio is usually expressed in a percentage. For example, a 10% duty cycle of any welder means a 1-minute operation duration & 9 minutes of cooling time.

With the amperage level of the welding instrument, the duty cycle will fluctuate in an up or down way.

When the welder is using a higher amp, it will decrease the duty cycle. That means with higher amp output, you will get less operation time.

For a 120 amp MIG welder, you will get a 35% duty cycle when the amp output is 60 amp. But for the same welder, you will get a 10% duty cycle while the amp output is 105 amp.

While using a 180 amp welder the duty cycle would be 30%

Speaking of a 3-phase welder, it will provide a 100% duty cycle even at higher amp output. These are best for heavy industrial work. However, they will require a lot of bucks!

Frequently Asked Questions

Final words

You already saw that the amp input is one of the key players in choosing the appropriate circuit breaker.

More current input means more amp and more amp means a powerful circuit breaker for smooth and safe electricity.

Hopefully, now you can play with your welder in a better way as you know the right size of the breaker for the welder.