Borrowed 115v noob question

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I don't own a welder but wanted to learn to weld so I borrowed my in-laws Lincoln SP-135 PLUS to teach myself.  I read lots of threads about welders and "tipsandtricks.com" videos and utube videos and I have reached a point where i MIGHT know enough to ASK questionsFirst there are a lot of opinions flying around about 115v welders being too small to do anything "serious" but several of these comments spark (<- ignore) more questions:"15A circuit will not even allow the 120V MIG to reach its full potential"pictures "showing the difference between a 20A circuit and a 30A circuit" with what i think is the same welderSooo ... first question.  My outside circuit is 14guage 15a .. I will be pulling 12guage and upgrading it to 20a  so i will have the supply per the manual.  I don't believe I can use 30a circuit without altering the machine and even thicker wire?in several places there are vague referenced to limited duty cycle on 115v machines.Sooo .. second question.  I want to know  about this RATING info.  Manual says 90a at 18vdc with 20% duty cycle and I understand this is 2min welding per 10min.  Is this a welding practice I need to follow or is this a guideline to keep from overheating and tripping the thermal shutdown?  I assume that the different switch positions mean different voltages but I find no place in the manual that says "E" = 12v or "F" = 50a  and it would seem that lower current would mean longer duty cycle?  I can't find any table relating switch settings to duty cycle.I can't even pull the trigger till I get the wire pulled and new outlet installed .. and in-law only has a shade 10 hand held mask so I ordered an auto-darkening helmet.. expect first arc by end of the week.  plenty to keep me busy.dmac257
Reply:Yes, for typical services, 14 gauge is only thick enough for 15 Amps, 12 Gauge is required for 20Amps.  30 Amps requires 10 Gauge.   It doesn't really matter what voltage.  Wire size is dependant on current flow.  There are some * (astrics) to those numbers and they are spelled out in the national electric code.   Your area might have updates (I know my county has some extras).  The concern is this, if you overload a particular wire, it can get hot enough to actually melt the plastic insulation.As for duty cycle.  To weld, your machine must draw a certain amount of power.  Power = Volts x Current.   So if you are only running on 115V you would require 2x as much current as a machine running on 230V.   Look at the discussion above.  Double the current requires thicker wire.   Melting insulation off wires inside the box (be it wires, or connectors to things like transformers, capacitors and all those little things in there) is not good.That being said, the duty cycle is typically about welding at full power (highest settings + highest wire speed + thickest wire).  Top it off, quality welders tend to have thermal shut offs.  Finally, quality welders are typically rated in worst case conditions - 100 deg F etc.So, for your typical use, there is a 'fudge factor'.  Besides, what exactly are you going to weld for 2 minutes straight?As for the settings.  There are no voltages associated with the settings because the actual voltage depends on more factors.  Once current start flowing, the voltage invariably goes down.   However, the machine does have settings on the inside door.  Use those numbers as a starting point and don't worry about voltages for now.As for what to weld on.  Hit the local steel supplier and ask for 'drops' of size 1/8".  10 or 11 gauge will also work well enough.  Set the machine up according the door chart and have at it.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:I ran a 115 unit on my RV plug.......30 amp, and it welded plenty hot, as long as you didn't want to go over 1/8". The little 115V welders have there place.HF 180 amp/240 volt Mig (cap mod)1987 Harley FLHTP (project)1990 F350 XLT Lariat S/C dually1990 S&S 11SC Cabover Camper2011 Ford Ranger S/C XLT
Reply:1st you can use the machine on a 15 amp 115v household outlet, if you stay at the lower end of it's output. For example if you needed to just weld thin sheet metal, a 15 amp circuit would most likely be fine. It's only when you want to start pushing the upper end that you would start tripping the breaker. A 20 amp line would be better, a 30 amp line would give the machine all the power it would want. Understand the breaker in the panel is rated to protect the wall wires, not the machine. You could plug a standard bulb into a 50 amp 115v circuit and the bulb wouldn't suddenly explode. The bulb would just draw the power it needed and thats all. The "extra" power would be useless, but there might be a danger if something was to short out possibly. Since the breaker is so much higher,  it would not trip probably even with the short. You would want to stay within a reasonable level if you were going to "overpower" it. Running 30 amp 230v welders on 50 amp 230v circuits is typical for example, and there aren't any issues doing so, since most machines come equipped with a 50 amp plug even though they only draw less than 30 amps..Next thing you have to understand with these small machines is voltage drop. When you run power thru small lines over long distance, the voltage drops. You might read 115v at the panel, but at the end of 200' of 14 ga extension cord, you might be reading only 100 v. Since the voltage is less than expected, the amps usually have to go up to give you the same output, often causing the breaker to trip, or  if the amp draw stays the same,  you loose output since the energy reaching the machine is lower. That's why often it's suggested to run larger amp circuits or to not use extension cords.As far as duty cycle, you may have 20% at 90 amps, but at the max of say 130 amps, your duty cycle is probably less than 10%. Part of this is due to the thermal load on the machine, and part may be due to the machine design. Some small machines have capacitors that help "store" up power and "boost" the power when welding. It helps them get a bit more output for short periods of time. It's sort of like putting water in a bucket vs just running from the tap. You can get a larger flow of water when the bucket empties, but then the flow drops off as soon as the bucket is empty until it gets a chance to "refill". At max power those caps get depleted fast and as soon as the caps are empty, you have exceeded duty cycle and the weld output drops off. High draw on the machine is also very hard on many of the components. You have often exceeded the duty cycle by quite a bit before the thermal cut out kicks in. Doing this over and over often causes the machine to begin to loose power and not weld as well, or causes components to burn out.General rule of thumb is the best 110v machines on the market top out at 1/8" material under real world conditions despite what the manufacturers lit might say. The manufacturer makes sure all conditions are perfect when they rate these machines. They supply them with unlimited power at the max standard operating voltage so input power doesn't hinder output. They have someone who really knows how to weld do the test so they don't loose any output do to inefficiencies from the operator, and they are running the perfect settings. They also run really short welds, so duty cycle doesn't come into play. They don't really need to build something, so if they only weld for 10 to15 seconds, to get the max, it doesn't matter... these conditions almost never occur with the average user.Small 110v migs have their place. They are great for sheet metal and small light projects. They are easy to plug in to standard outlets and are usually fairly portable. They also often allow guys like you the chance to learn without having to do anything more than plug it in. As long as you recognize the limitations and stay within them, you are fine. However most hobby users quickly outgrow the limitations of these small machines when they want to start welding heavier materials like 3/16" and 1/4". 230v machines with an output in the 180 to 200 amp class are usually better choices in the long run even though you loose the ease of plugging in to any outlet.Last edited by DSW; 05-06-2013 at 03:16 AM..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by con_fuse9Yes, for typical services, 14 gauge is only thick enough for 15 Amps, 12 Gauge is required for 20Amps.  30 Amps requires 10 Gauge.   It doesn't really matter what voltage.  Wire size is dependant on current flow.  There are some * (astrics) to those numbers and they are spelled out in the national electric code.   Your area might have updates (I know my county has some extras).  The concern is this, if you overload a particular wire, it can get hot enough to actually melt the plastic insulation.
Reply:Originally Posted by desertscoutI ran a 115 unit on my RV plug.......30 amp, and it welded plenty hot, as long as you didn't want to go over 1/8". The little 115V welders have there place.
Reply:Originally Posted by DSW1st you can use the machine on a 15 amp 115v household outlet, if you stay at the lower end of it's output. For example if you needed to just weld thin sheet metal, a 15 amp circuit would most likely be fine. It's only when you want to start pushing the upper end that you would start tripping the breaker. A 20 amp line would be better, a 30 amp line would give the machine all the power it would want. Understand the breaker in the panel is rated to protect the wall wires, not the machine. You could plug a standard bulb into a 50 amp 115v circuit and the bulb wouldn't suddenly explode. The bulb would just draw the power it needed and thats all. The "extra" power would be useless, but there might be a danger if something was to short out possibly. Since the breaker is so much higher,  it would not trip probably even with the short. You would want to stay within a reasonable level if you were going to "overpower" it. Running 30 amp 230v welders on 50 amp 230v circuits is typical for example, and there aren't any issues doing so, since most machines come equipped with a 50 amp plug even though they only draw less than 30 amps...
Reply:The machine is rated for 90 amps at 18V running on a 20amp circuit. To get to 135A you need a 25A or higher outlet to plug into. The cord running to the machine from the outlet needs to be 14ga wire and less than 50ft long to run the rated 90 amps. Or 12ga wire less than 50ft long to run 135A. At least those are the specs for that machine from the manual. See page 8 http://www.lincolnelectric.com/asset...OLN3/im725.pdf
Reply:Originally Posted by dmac257I am limited to the single outlet in the back yard (soon to be upgraded) but when you say "a 30 amp line would give the machine all the power it would want" would I have to alter the machine's cord also?  It is not mine so I will not alter it.  The house outlet I can play with.
Reply:Run a dedicated 20amp line for the 135. It will be way mo' better than running a little generator.If you decide to run a 30amp line you do not need to alter the welder.You'll probably never hit the duty cycle so dont sweat it, and as you mentioned the 135 has a thermal shut off. If you do exceed the duty cycle often then it is time for a new machine anyway.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:OK .. i am getting even more confused because everyone keeps jumping from 20a to 30a.  The manual says I need a "25a branch circuit" to get full use of machine.  It also says I can use a 12 gauge extension cord less than 50 feet long at full power.  The 20a branch circuit will use 12 gauge wire.  I can find no code description of a 25a branch circuit.  Someone said they ran their welder from a RV outlet but that is not the same receptacle and the welder.  Is a 25a branch circuit a dedicated single outlet with a 20a receptacle and a 25a breaker?  If you run a 115v welder from a 30a receptacle do you need a plug adapter or something.dmac257
Reply:Originally Posted by dmac257OK .. i am getting even more confused because everyone keeps jumping from 20a to 30a.  The manual says I need a "25a branch circuit" to get full use of machine.  It also says I can use a 12 gauge extension cord less than 50 feet long at full power.  The 20a branch circuit will use 12 gauge wire.  I can find no code description of a 25a branch circuit.  Someone said they ran their welder from a RV outlet but that is not the same receptacle and the welder.  Is a 25a branch circuit a dedicated single outlet with a 20a receptacle and a 25a breaker?  If you run a 115v welder from a 30a receptacle do you need a plug adapter or something.dmac257
Reply:You could run 10 gauge wire for a 20A setup.  Then if you ever want to upgrade to 30A, it's just the breaker and outlet."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:This is what I did in preparation to see what my Lincoln can do "under real world conditions", as in my garage. I take what I read on the internet and hear at the LWS from guys trying to sell "more power" with a grain of salt. MIG 1/2" plate with this little machine? No way, but I already know how to do that in compliance with code, with a much more capable machine. A good weld of 1/4" steel with this little Lincoln is what I'm shooting for here. Maybe I'm dreaming. So, back to hotrodding the Lincoln, I had a 30A branch run from the box to the garage using 10ga wire. I wanted to limit my ciruit to the 25A spec and not rely soley on the welder's own internal breaker so I found a 25A breaker on ebay for $5 (not easily found elsewhere) and had that installed, together with a standard 120V RV receptical. I had this done by our electrician as power is ALWAYS going into or out of the house (we hava a PV system tied to the electric company) so I'm not mucking with that box for anything. That done, I made my own 20' 10/3 power cord to provide enough reach from the receptacle to the welder. The voltage drop through and extension cord can be substantial. There are calculators online which show this. Since my welder has a 25A plug for the power cord (one blade is sideways instead of both vertical like a 20A plug, cf DSW's pic), I looked for a complementary 25A receptical, very rare. They seem to be only used on water coolers and don't seem to be a regularly stocked item anywhere. I gave up looking, removed the plug from the welder and just hardwired the power cord in its place. Stuck an RV plug on the other end and done.XMT304 (school)SP125+ (home)HF 4x6 BandsawGood judgement comes from experience and much of that comes from bad judgement.
Reply:Originally Posted by dmac257Someone said they ran their welder from a RV outlet but that is not the same receptacle and the welder.dmac257