[JakeDJones]

Hello, new the page but have been trolling in the shadows for a good long while. I went and bought a Lincoln square wave TIG 255 this morning from an old woman I knew whos husband was a welder and passed away and she was selling some of his old equipment, anyway, she was selling off a square wave 255 in nearly brand new condition. been shop kept the hole 9 very well taken care of. I wouldn'y have otherwise bought the machine but she made a price i couldnt otherwise refuse so at a handsome 500$ i am the proud new owner of SW255!. this is the first transformer machine ive ever owned, all of my other machines are inverters or engine drive. im looking at putting this in my home garage, my shop is 30 minutes away and id like to have a good machine at home so i dont have to go to the shop to do most of the small aluminum repair and fab work i do. SO long story short heres the big question!. have 2 100A panels at my house, and have 3 60A breakers dedicated to welding plugs in the garage. this machine was obviously hard wired into its rpevious power source. it has an input line consisting of 6/4 wire. would i be safe putting a standard 3 prong welding plug on this and running like that as the max output i expect to achieve on this machine will be 200A? or should i pay an electrician to wire in this machine. the manual states it needs a 100A breaker and i know breakers are decided upon base on duty cycles. but ill be honest im no where near an electrician so if you could dumb any answers down best you could that would be great!

[Poland308]

Post a pick of the manufacturers name plate. It will tell you input voltage and max amps.

[JakeDJones]

Here

[Poland308]

Max input amps is 81 on 208 v

[Franz©]

Question really becomes how often will you be using the machine at maximum output.

Second question is what is your actual voltage from the panel?

If your line voltage is 240 nominal, you should have no problem squeezing 60 to 70% of machine capability through one of your 60 amp plugs. This may be lower if the breakers on those plugs are Murray magnetics.

Best way to find out, get a range cord that plugs in your range/welder receptacles and a 411/16 box with a blank cover and splice the machine cord to the range cord in the box.
Probably a good idea to open up the Lincoln and see which wire is connected where before you splice.

[JakeDJones]

Thank you all for your help, my dad is a safety superintendent for a big chemical plant and he supervises the pipe fitter out there, took the wiring diagram and info off the machine to his master electricians who also happen to be welder, the likelihood of me using this machine where it’s at to it’s fullest will be slim to none. Went to the local electrical supply today and picked up a 4 prong 50A plug. Per the electricians recommendation. Just plugged her up for the first time about 15 minutes ago, fires right up fine with no issue but I won’t be able to see how it welds until tomorrow. So far I’m happy with my purchase, we shall see if the machine is in good working order tomorrow when I put it through the paces

[Bill Beauregard]

I don't believe it is relevant how often. Install the welder, use it a little at first, like it, you use it more.

I will assume you are using 230 Volt household USA power.

NEC allows a reduction in conductor size based on duty cycle. The factors in 630.11(A) call for 46.62 Amp supply.

Some terminal is bound to limit temperature rating even if you use 90 D C insulated wire. Use chart for 75 D in chart 310.15(B)(16).

#8 copper should serve your needs.

Breaker size should begin at 80 amp, but could be upgraded as necessary up to 120, I don't believe that is necessary.

Bear in mind the length and size of conductors beginning at your utility transformer is important to supply adequate voltage to the welder. I know of a MM252 welds like bird $hit. It shares 250 feet one way of #6 copper with other loads. I have its twin at home, it is a wonderful welder.

Willie