Mig welder power requirements

Mig welding machines are essentially a power source, a transformer.

They are designed to convert unusable and unstable voltages down to a more suitable voltage that can be used in the mig welding process. This means stepping down the voltage from something like 240 volts down to 20 volts.

Some power requirements you need to check out first are that the machine you plan on using is suited to the power that is available in your workshop, shed or factory. Household premises usually have single phase power supplies where as industrial workshops will have three-phase power supplies. Depending on where you are located in the world i.e. the USA or Australia will dictate what power you have available. So for people who live in Australia our three-phase power is usually 415 V, and our single phase is 240 V.

Inrush current / start up current

You're also going to have to make sure if you are using a big machine, something like an OTC XD400. That your power outlet is big enough to handle what is called the in rush "start up current". This is the initial surge of power when the trigger is pulled. These types of heavy duty industrial machines offer excellent welding power and performance, but because they are so powerful the initial surge of power can be quite high. This means you need to make sure that your breaker or fuse, wiring, and power outlet can handle this higher inrush current.

Wall socket and power lead plug

Note: Most single phase machines will come with a 15amp plug (in Australia anyway), yet most household power points are only 10amp sockets. This means you will need to get an electrician to come around and install a bigger fifteen amp socket. The difference between the 10 amp and the 15 amp plugs are that the earth pin is much larger on the fifteen amp plug. By having this pin larger you are not able to plug it into the normal ten amp socket. The electrician will put in a fifteen amp socket which will accept the larger pinned plug.

Obviously the machine has the larger amperage plug to help with the welding power load.

If you plan to use a generator with your mig welding machine, again make sure that you have enough power to run it. If you are going to be welding outdoors with either a generator or just off the power outlet from inside you are going to have to use a power cord extension lead. As the power lead is long you are going to experience a little voltage drop. So if you had say 3 or 4 long extension cords connected so that you could weld way down the back yard, you will notice that the power will not be the same as if it was back in the workshop. So you will have to increase the power of the machine slightly to compensate for the power loss.

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