[maddog1]

I'm interested in purchasing a Mig welder rated for plug into a standard outlet of 115/120 volts.

In the fine print there's a note that says to run the machine's maximum output the branch circuit should be rated at 120 volts/25 amps/60hz. What am I missing here in this footnote? Is there such a thing as a single pole 25 amp circuit breaker?

Its confusing because the power info states to plug it into a 115/120 20 amp rate receptacle with a 20 amp breaker. Then outside the chart, it makes a statement about a 25 amp breaker. And it makes no mention of wire size within the circuit.

It also goes on to say that if an extension cord is needed it should be a minimum of 12 gauge but #10 or greater would be better. And all this comes from a quality company-Lincoln Electric. I thought I would ask here first before calling Lincoln to hear what they have to say about it. Thanks

 

[surferdude2]

They used those type of mig welders on every restaurant job on stainless steel hoods that we provided and they never blew the job site 20 amp beaker. We were normally around 30' from the power pole where the installer plugged the 50' cord (12 ga.) he ran off of to power the welder. You won't likely be running under that large of a disadvantage but it shows the possibilities.

I suspect the manufacturer is hedging his rating in case you run the welder on a 100% duty cycle operation and full power like on a production line where the new work continuously appears. Under those conditions, it will likely provide its own duty cycle rest time by tripping the breaker.

 

[joed]

They figure most people will not be using the unit at full power. That means it will be fine on a normal 20 amp circuit for most uses.

 

[Oldmaster]

When I went to welding school I was told the higher the welding current the lower the duty cycle. Therefore 100% would be the lowest welding current, not the highest.

 

[surferdude2]

When I went to welding school I was told the higher the welding current the lower the duty cycle. Therefore 100% would be the lowest welding current, not the highest.

Your instructor was telling you that if you used a welder at a 100% duty cycle (constantly welding) you would need to lower the amperage or else the welder would burn down. It is necessary to read the welders rating tag to see what the duty rating is in order to know how much welder you actually have as versus what the manufacturer chooses to advertise as the amperage rating only.

For example, a given welder may be touted as a 200A welder. However, careful reading of the documentation that comes with the unit may show that the welder can only produce this rated power with a 20-30% duty cycle (or even less). There is a huge difference between this welder and another 200A welder that can produce its rated power continuously (aka 100% duty cycle) -- both in work capability, and in long term reliability.

Professional welders understand that almost all welding equipment manufacturers rate their welders using the maximum current that can be produced as the key specification -- not the 100% duty point. So to compensate, a pro will buy a 225-250A welder in order to get the100-150A 100% duty performance that they need to do their work.

 

[Calson]

The 110 VAC welders are fine for light gauge metal but check the specs to be sure that it will weld the types of materials you plan to use. MIG further reduces the penetration depth of the weld as compared to the same arc welder without MIG wire and argon gas.