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What Size Breaker for Welder? (Quick Answers)

Welding is a process by which you can join two or more pieces by heat, pressure, or both, and as the parts cool down, a bond forms called the weldment. Usually, you will see people welding pieces of metal, thermoplastics, and wood. If you are unsure what size circuit breaker you might need, follow along, and you will have your answer.

Welder breaker size

Welders are high-power-consuming machines and come in different variants. Generally, welders require a 30A to 40A circuit breaker to work optimally. Please note that the circuit breaker rating should not be less than 30A, as welders need loads of current to operate.

As mentioned previously, welders consume loads of power as they produce high heat and pressure to join pieces of various materials. Therefore, they require a high-capacity circuit breaker to tolerate all the current flowing through the circuit while the welder is operational. However, welders have variants, and not all welders can run on the same circuit breaker.

Below, you will find a list of commonly used welder variants and what capacity breaker you might need for each. Welders vary in the amount of voltage they run on.

110v welder:

Welders that use 110V are small welders. You will find them in most homes where people tend to repair things themselves. Since this is a relatively small welding machine, it does not use a high number of currents. So, you can use a simple 30A circuit breaker for a 110V welder. If you think the circuit breaker rating is too small, you can use a 35A circuit breaker if available.

200v welder:

A 200V welder also requires a 30A circuit breaker. 200V welders use significant power. Such high-power-consuming machines require around 30A to 35A of current. Therefore using a 35A circuit breaker for a 200V welder will be adequate.

220v welder:

Professionals use the standard 220V welder machines. You will see these 220V welders in shops and construction sites. These machines pull in heaps of power to operate. 220V welders need 220V and around 30A to 35A of current. Hence, you can pair a 35A or a 40A circuit breaker with a 220V welder.

240v welder:

Similarly, 240V welders are better than 220V welders. In sites where the weldment is a crucial process, you will see people using 240V welders. Although 220V welders are more common, some people prefer the 240V welder machines to the 220V variant because they are more powerful. As they are more powerful, you will need a 40A circuit breaker to handle all the current.

For small welding machines, such as the 110V and the 200V variants, you can stick to using a 35A circuit breaker. These machines typically use less than 35A.

As for the 220V and 240V welding machines, the powerful ones, you can use a 35A or a 40A circuit breaker. It is better for such devices if you use a 40A circuit breaker. Since welding machines do not generally have a power rush, there is almost no risk of the current level reaching above 35A and causing electrical hazards.

30 or 50 amp breaker for a welder?

Most people have the confusion whether they should use a 30A or a 50A circuit breaker. You will often find such people asking which circuit breaker will be most suitable for their welding machine. The answer depends on what kind of welder they are using.

For small welding machines, the 110V and the 200V variants, you can use a 35A circuit breaker. A 30A circuit breaker will be insufficient for the welder as it will use around 30A to 35A. Installing a 30A circuit breaker for these welders will not benefit you as you might frequently observe the circuit breaker tripping.

If you are considering a circuit breaker for a 220V or a 240V welder, you can use a 40A circuit breaker. A 50A circuit breaker will be disadvantageous. It will be too large for the welders, and any machine malfunction will cause the overloading of the circuit.

However, if you know that the electrical circuit can handle more than 50A of current, you can install a 50A circuit breaker for 220V or 240V welders. Welders often tend to pull more current while working for a long time.

How many amps does welder use?

Knowing the amount of current a welder consumes can help determine the best-fit circuit breaker. We have simplified the power draws for you in the following paragraphs.

Smaller welding machines, the 110V and the 200V variants, use about 20A of current. Although these devices use less than 20A, the recommended circuit breaker size is 30A. A 30A circuit breaker will tolerate any additional current flow but restrict the overloading of the circuit.

Larger welding machines, the 220V and the 240V variants, require a 30A current to function. The recommended size of the circuit breaker is 50A on the condition that the electrical circuit can handle more than 50A. If the electrical circuit cannot allow more than 50A, you can use a 40A circuit breaker.

3 factors that determine welder breaker size

Several factors determine the breaker size required for a welder. Keep these points in mind, and you can decide which breaker size will be most suitable for your welder.

Circuit capacity:

Before installing a circuit breaker, check how much the circuit can handle. If the electrical circuit allows 25A and you install a 30A breaker, the current flow will heat the wires, resulting in electrical hazards. So, use a circuit breaker that will prevent overpowering the circuit.

Amount of current required:

The amount of current required by the welder is something you keep in mind before determining the breaker size. The current requirements help decide the minimum size of the breaker. If your welder pulls around 20A, you should not use a circuit breaker with a capacity of less than 20A as the minimum rating is 20A.

125% of the current required:

Since circuit breakers turn off the power supply when the amount of current goes beyond the breaker’s ratings, you should leave some headroom for additional current. Calculate the 125% of the current and use the closest rating you can find. For example, 125% of 20A is 25A. So, use a 25A circuit breaker for this case.

These are essentially the main factors that influence the circuit breaker size. Consider these points to help decide which circuit breaker will be the best fit in your case.

How to choose a breaker for a welder?

Choosing a circuit breaker for a welder is not challenging. You can do it yourself by following the steps listed below:

Calculate the current used:

You can obtain the amount of current flowing through the circuit by using an ammeter. For this, you are going to need an ammeter that has a clamp attached to it. The clamp clamps around the wire you want to measure the current in.

Using the ammeter, clamp the live wire of the welder. The reading will give you the value of the current flowing through the wire. Before using the ammeter, ensure the welder is running.

Calculate 125% of the current:

After you have successfully obtained the current flowing through the circuit using an ammeter, you need to calculate 125% of the current. For example, if you have got the value 30A, you will get 125% of 30A by multiplying 125 by 30 and dividing it by 100 because of the percentage. You will get approximately 38A.

Check the circuit capacity:

The circuit capacity is an important factor influencing the circuit breaker size. Having a larger circuit breaker than the circuit can handle will result in the wires heating up to unsafe levels without any stop in current flow. You should, therefore, use a circuit breaker smaller than the maximum the circuit can handle

Choose the circuit breaker:

After you have obtained 125% of the ammeter reading and how many amperes the circuit can handle, you can finally choose the circuit breaker. According to the previous example, if 125% of the current is 38A and the circuit can handle more than 50 amperes, you can use a 40A or a 50A circuit breaker. On the other hand, if your circuit breaker cannot handle more than 45A, you can use a 45A circuit breaker to stay safe.

By following these steps, you can achieve the best-fit circuit breaker for your welder. If you need help, feel free to call the local electrician.

Final Thoughts

Choosing the best-fit circuit breaker for a welder is crucial to safety. Failing to use an appropriate circuit breaker can result in fatal consequences. However, choosing the right breaker size is not difficult, and you can do it yourself without any additional help.