DC stick welding - Q. re amps supply

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Sorry to take up space with another post on supply amps, but I am still not sure how to think about this since opinions seem to vary quite a bit.  My welding supply, which is fine for my Thunderbolt, is 230V on a 50A service supply, 60Hz, single phase.It's the 50A breaker that concerns me.  I am thinking about getting an older Miller Dialarc250 AC/DC machine.  It looks to me as though the top amps input at 230V which these machines are looking for is 90A AC and 70A DC, although the exact figures are somewhat model dependent.  I'm no electrician, but it seems to me that putting in a 100A breaker would get me well up into industrial-installation territory, and I am not willing to do that.  I'm a home garage welder, and what I do are jobs like a small boat trailer, or a shop cart.  I run 7014, 6013, and similar on material such as 1/8 or 3/16 mild steel angle.  If I were to get that Dialarc and plug it into my 230V 50A supply, would something bad be likely to happen?  As I said, I have heard differing stories about this.  Advice appreciated.     -Marty-
Reply:it will run your machine in the lower ranges you are talking about. you just have to keep in mind if you are tempted to do heavy weldments at higher amps you will quickly outrun the breaker and the wiring.
Reply:To start you probably can not just put in a 100 amp breaker. The wiring is more then likely only rated for 50 amps. That being said that machine will probably be alright on the 50 amp circuit as long as you are not running it up at the high end of it range.Mike
Reply:Well first thing you need to do is determine what size wire is actually in the wall?  Believe it or not NEC code actually allows Oversized Breakers on Undersized Wires for welders and only welders since most welders are not 100% duty cycle.  (Note it is critical that nothing else besides the welder be plugged into that circuit and the amount of oversize is related to the duty cycle of the welder so if you buy a different welder then you have to revisit the NEC code and run the calculation formula again to see if you still okay).In reality, if you are already have an oversize breaker on undersize wire then trying to run a Dialarc of that would be real bad news and likely a fire real quick like.  If you have a true 50 amp circuit with appropaiate size 50 amp wire (likely 6 ga) then you might be able to up size the breaker to get close to the dialarc's power requirements (again consult the NEC code formula to see what is permissible for the wire you have in the wall).  Remember though doing this will limit that circuit to only use for the Dialarc welder and absolutely nothing else can be branch powered off that circuit.  No plugging an air compresser into that circuit.  Or plugging a plasma etc into that circuit etc.If none of this makes sense to you then consult a qualified electrician as electricity is dangerous if you do not understand it.In my case, I am actually already running a Miller Thunderbolt with an oversized 40 amp breaker on undersize 10 gage wire (10 gauge wire is only rated for 30 amp continuous load).  My set-up is easily permissible under NEC code with the Thunderbolt's low duty cycle.  While I would love to have a Lincoln Idealarc it would cost me a fortune to bury bigger size wire to power it out to my barn even if somebody gave me the welder for free.  While I like both Lincoln Idealarc's and Miller Dialarc they simply do not make practical sense for many home owners if you are faced with expensive supply power hurdles.  I myself will be keeping my Thunderbolt for this very reason as it is easy to power on wire as small as 12 gage.Last edited by rankrank1; 01-12-2014 at 06:30 PM.
Reply:I run my Dialarc on the same 50 amp breaker that I used to run my Thunderbolt on with no problems.Note: this is all on 6 gauge Copper wire, not Duty Cycle rated 10 gauge wire.This past Fall when I used a bunch of 3/4" plate to make the backing plate for forks on a skidsteer. I was running DC hot(135?) on 1/8" 7018. I ran 10 rods straight before I tripped the breaker. I let things cool till I needed to run some horizontal welds on 5/32" 6011 which I ran AC hot(145?) also. I think the 6011 I ran 6 or 8 rods straight?Go ahead and use it on the 50 amp breaker and enjoy!Last edited by drujinin; 01-12-2014 at 06:22 PM.
Reply:Run my TM-500 ac/dc on a 50 amp works fine used up to 300 amps and did not pop .
Reply:I run my Dialarc and my Airco tig on 60 amp breakers.  I would not be scared to use 50 amps, just prefer running the larger wire and breaker.However, I don't run them near their max - I just have them because of their high duty cycles in the mid-ranges where I use them.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:That's all helpful.  Thanks, guys.    -Marty-
Reply:Yeah do a 60 amp breaker and 8ga wire if its for less than 30 feet and on a duty cycle should be fine.I have a 235 amp welder on a 60 amp breaker using less than a foot of 8ga to run from the breaker to the plug, works good.My machine calls for a 60 amp breaker, I believe it would have worked fine on a 50 amp breaker.old Miller spectrum 625 Lincoln SP-135 T, CO2+0.025 wireMiller model 250 and WP-18V torchCraftsman 100amp AC/DC and WP-17V torchCentury 115-004 HF arc stabilizerHome made 4 transformer spot welderHome made alternator welder
Reply:I've run a Invertec 275 on a fifty amp breaker.My breaker was twenty amp and I was running my invertec at 150 amps no problem, but if i went over that for any length of time i would heat up the breaker, I used to have a Airco 300 amp stick welder, about the size of a pallet almost and it said a  70 amp breaker minimum for 250 amps of weld current at 80 percent duty cycle and I ran it on a 50 amp breaker, no problem at 270 amps. prolly 20 % duty cycle, but I credit it to my heavy wire
Reply:I run my IdealArc 250/250 and my Lincoln 180 mig on a 50 amp breaker. Not together, of course.  Never tripped the breaker even when running the mig maxed out. The highest setting I've run the IdealArc is about 160 amps DC just as an experiment.  You can weld pretty heavy homeowner type stuff at that level. I rarely run much over 120 amps for anything at home, preferring to make multiple passes instead if necessary.
Reply:Inverter machines draw less apparent power than a transformer machine, they will put out more weld amps before they flip a breaker.old Miller spectrum 625 Lincoln SP-135 T, CO2+0.025 wireMiller model 250 and WP-18V torchCraftsman 100amp AC/DC and WP-17V torchCentury 115-004 HF arc stabilizerHome made 4 transformer spot welderHome made alternator welder