I have a wiring question

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I have a 220 volt plug in my garage for my welders. If I hook a volt meter to the ground and  each hot side of the plug I get 120 volts from each hot wire. If I hook my volt meter to both hot wires I get 220 volts. My plug has to hot wires and a ground wire(some plugs have a ground and a neutral) but for our discussion welders use two hot wires and a ground. If my plug is wired with #10 wire and a 30 amp breaker I should be able to draw 30 amps off each side of the plug. That totals up to 60 amps from that plug. I have run my Lincoln 225 at almost max capacity and have never tripped the breaker and I'm pretty sure that welder draws more than 30 amps. I also have run my hobart handler 210 at max setting and have never tripped the breaker. I am going to go out in the garage when it gets light out and crank my 225 to max and see if I can trip the breaker.Let me hear what everyone thinks about my theory. Stay tuned I will let you know if I was able to pop the breaker.
Reply:Originally Posted by kctgbi should be able to draw 30 amps off each side of the plug. That totals up to 60 amps from that plug.
Reply:Originally Posted by KelvinBZZT.. Wrong.
Reply:If I understand US electrical systems correctly we are talking about a split phase system, where you have a transformer putting out 240V total, but with a grounded center output - making it 0V on the center ground connection, 120V on one leg of the transformer and 120V on the other leg.You can get 120V and 30A from each leg vs. ground (that is, 2x30A at 120V), or 240V and 30A between the legs. 2x30A is not 60A, even if the total power you can get from 2x 110V 30A is the same as 1x 110V 60A.Here in Sweden we have 3-phase systems with 230V phase-ground and 400V phase-phase, commonly with 16A main fuses in most homes. Quite a bit diffrent...
Reply:Originally Posted by G-sonYou can get 120V and 30A from each leg vs. ground (that is, 2x30A at 120V), or 240V and 30A between the legs. 2x30A is not 60A, even if the total power you can get from 2x 110V 30A is the same as 1x 110V 60A..
Reply:Originally Posted by G-sonIf I understand US electrical systems correctly we are talking about a split phase system, where you have a transformer putting out 240V total, but with a grounded center output - making it 0V on the center ground connection, 120V on one leg of the transformer and 120V on the other leg.You can get 120V and 30A from each leg vs. ground (that is, 2x30A at 120V), or 240V and 30A between the legs. 2x30A is not 60A, even if the total power you can get from 2x 110V 30A is the same as 1x 110V 60A.Here in Sweden we have 3-phase systems with 230V phase-ground and 400V phase-phase, commonly with 16A main fuses in most homes. Quite a bit diffrent...
Reply:Originally Posted by DSWCorrect. He will have 20 amps available 230v power.Your AC 225 will draw close to 50 amps wide open. You should be tripping that 30 amp breaker at the upper end on that machine.  Most AC 225's I've worked with will trip a 30 amp breaker running 1/8" 7018, especially at the upper end of it's range.If not, that's a sign that you may have a problem that needs to be investigated.While it's not common, I have seen breakers go bad and lock on. Try and see if you can cycle the breaker a few times. Usually a bad breaker will either not turn off, or if it does, it will not go back on. If the breaker doesn't move freely, it's probably a good idea to replace it anyways. Breakers are cheap. New homes, because you exceeded the amp rating on the wire because the fail safe ( breaker) went bad and started a fire, are expensive.If you run a bunch of beads with 1/8" 7018 and the breaker doesn't trip, check to see if the breaker is warmer than other breakers immediately afterwards . If so, that's generally a sign somethings not right.
Reply:http://en.wikipedia.org/wiki/Split_phaseA single phase, but with a grounded center making two diffrent voltages available.
Reply:I know a electrician I will call him today.
Reply:You can draw up to 30 amps at 240 volts or you can have two 30 amp 120 volt loads, if you also have a neutral wire available, but you cannot draw more than 30 amps through #10 wire and a 30 amp breaker for very long, unless the breaker is defective.However, you can get by using a 30 amp circuit to run a Lincoln 225 if you don't need more than about 60% of it's output for extended periods. Welding is a constantly varying load and circuit breakers trip when the average current load exceeds it's rating for more than a time defined by the trip curve of the breaker's design, or if there is a short circuit. If your average load current does not exceed the 30 amp breaker rating for more than a few seconds at a time it will not trip. Some years ago we needed to do some welding out near our well house (about 150' from the house). The well house only has a 30 amp panel and #10 ga branch circuit feeding it and our Bobcat 225NT wasn't available that day. We had an old Lincoln 225 and decided to hook it up to the well house panel to try to get the job done. We were welding mostly 2 X 2 X 1/8 steel angle so the welder never ran at full output or for very long at a time, It did the job just fine, and better than I had expected, however I wouldn't consider it the right way to power the welder for every day use.  When used in the shop it was always powered from a 50 amp 240 volt circuit.CharleyMiller MM252Miller Bobcat 225NTMiller DialArc HF / DIY Cooler2 Victor O/A TorchsetsMilwaukee 8" Metal SawMilwaukee Dry Cut "Chop" Saw 5 Ton Wallace Gantry Various Grinders, Benders, etc.
Reply:Originally Posted by kctgbI'm kind of confused when you say split phase system as I have a single phase hookup to my house.
Reply:and if you look at your residential meter it indeed does read 240v Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Well I have talked to a electrician and this is why he thinks I'm not tripping my breaker. I went out and burned 13 rods of 7018 and went over to feel the wires and the breaker and nothing is close to being warm. I replaced my breaker and nothing happened so I don't think it was the breaker. The electrician tells me if I run the welder at max for very long the breaker will trip but because my 220 plug is only a few feet from my box it isn't creating enough resistance or heat to trip the breaker. If the plug was farther away it would trip much quicker due to the build up of resistance witch will cause heat.I guess it kind of makes sense.
Reply:Originally Posted by kctgbI have run my Lincoln 225 at almost max capacity and have never tripped the breaker and I'm pretty sure that welder draws more than 30 amps. I also have run my hobart handler 210 at max setting and have never tripped the breaker. I am going to go out in the garage when it gets light out and crank my 225 to max and see if I can trip the breaker.
Reply:If it helps for anyone to understand, when using a welder on 220v, 30 amps for example, 30 amps flows from one hot lead to the other hot lead, and zero flows in the neutral lead.  That's why it is 220x30amps, not 60 amps.    With a 50 amp load, the neutral still should be carrying zero current.Ken
Reply:[QUOTE=DSW;1058691]Correct. He will have 20 amps available 230v power.ok,my curiousity is killing me.where did you get 20 amps from the 30 amp breaker ?miller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet
Reply:[quote=boatbuoy;1064101] Originally Posted by DSWCorrect. He will have 20 amps available 230v power.ok,my curiousity is killing me.where did you get 20 amps from the 30 amp breaker ?
Reply:i thought it was some of that new math they teach these days.miller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet