Breaker For Lincoln Idealare 300 Welder

I have a chance to buy the welder for a $100, but has no cables. I have 50 AMP breaker for my welder now, will that breaker be big enough for the bigger welder if I don't go ever 150-175 amps and that would be seldom.

Very likely that you will be just fine. Easy way to make sure is look at the info tag on it if it is still there and see what amp draw is says it has.

I cant say sitting here if a 50 amp breaker will pass whatever current the welder draws without knowing the welders primary current draw at the heat range youre welding at, but it is likely if youre welding at a low amperage setting it may well do so. What matters electrically is if the branch circuit wiring has sufficient ampacity. If you want to weld at higher amperage (that would trip a 50 amp breaker) then you have to increase the branch circuit wiring ampacity and then protect it with an appropriate sized breaker.

The way its done (at least how I did when I was a design engineer) is you FIRST calculate the load,,,,,,,Then you select feed wires having an ampacity of at least 125% of the maximum continuous load,,,,,,,,Then you select the overcurrent protection device appropriate for the wires ampacity. For example, on a branch circuit if I calculated the max continuous load was say 15 amps, Id specify 20 amp rated wire and protect it with a 20 amp circuit breaker.

Many typical tombstone AC Buzz Box Welders are straight 240 volt (i.e. NO 120 volt loads and no Neutral required) and the branch circuit feed consists of two Hots (L1 & L2) and an Equipment GroundING Conductor. Of course, if a welder required BOTH 120 and 240 volt supply, then the branch circuit consists of two Hots, a Neutral (GrounDED Conductor) and an Equipment GroundING Conductor.

Best wishes

John T

Go for it. You should be fine. Just make sure all your wiring is up to handling the 50 amps if you do happen to be running the machine hard. My Idealarc 250 is rated for a 50 amp breaker. Never get anywhere near the high end of its output on general maintenace welding. Don"t miss that deal over a breaker size. Worst thing that will happen is she will trip the breaker and that means break time cause you were working too hard anyway!

My welder would trip the breaker if I used more than half a stick. The set screw in the breaker was not tight enough against the wire. Tighten it up and all the trouble went away. It took awhile for me to find that little problem maker though.
SDE

Lincoln Electric, like most major welding equipment manufacturers, has Operators Manuals online with the appropriate wire/fuse size for respective available input voltages.

http://www.lincolnelectric.com/en-us/support/Pages/operator-manuals.aspx
Just pick out the Idealarc 300 model you have, the information you need is in the manual.

Using 220 input voltage, a 50 amp fuse will be a little light at higher welding amperages. We wire directly to the 100 amp breaker at the top of the breaker box.

Idealarc 300 or Idealarc 250? I ask because an Idealarc 300 would be either a TM series or a TIG 300 and use more power than a 250? A 250 will go to 300 amps on AC. Does the machine have power factor capacitors? I think a 250 will draw about 72 amps(depending if it has PFC's) but considering the 30% duty cycle at 200 amps, a 50 amp breaker should be OK. I had a Square Wave 255 Lincoln TIG welder that ran fine off a 60 amp breaker. The electrician said the duty cycle of the machine makes a difference in the size of breaker that can be used.

I have an Idealarc TIG 300 that I put on a 100 amp breaker. If used on AC with the TIG and high frequency it will pull more than with just stick welding. You can get the manual online from Lincoln or if not available I could scan mine for you. They do not come stock with power factor correction as it is an option. Mine is a 1985 model. You will need the serial no. to get the right manual.