Dual 220 plug for welder/plasma cutter combo

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My 50a welder outlet is 20' from my welder so I run a #8 extension cord to it. I'm thinking about getting a plasma cutter and wonder if there's a way to create a dual plug on the end of the cord so the plasma and welder can be plugged in at once. They'll run separately, never at the same time. Sure I can unplug one and plug in the other but was just curious about the possibility.And BTW, are most 220v plasma cutter plugs Nema 6-50P like a welder?
Reply:Yes same as the welder style. I don't see why you could
Reply:Couldn't gang 2 4x4 boxes and wire up 2 receptacles. Kind of like 110 volt duplex outlets, using 1 cord.
Reply:Better to just put in a 2nd receptacle next to the first. Depending on how your first was done you may be able to pull a second set of wires to have another circuit.
Reply:Originally Posted by JD1My 50a welder outlet is 20' from my welder so I run a #8 extension cord to it. I'm thinking about getting a plasma cutter and wonder if there's a way to create a dual plug on the end of the cord so the plasma and welder can be plugged in at once. They'll run separately, never at the same time. Sure I can unplug one and plug in the other but was just curious about the possibility.And BTW, are most 220v plasma cutter plugs Nema 6-50P like a welder?
Reply:Originally Posted by OscarYou could.  A couple  4" square boxes (the deeper ones), two 6-50R receptacles, some 1/2"  or so knock-out fittings, a couple raised front covers for 2".  You could even weld them together if you space them just the right amount so the front covers aren't binding against each other.  Can you tell I'm making something similar right now?
Reply:Maybe use two close nipples or chase nipples side to side so the boxes stay in line and tight.You would be smart to use two 4 11/16" boxes instead of 4 square 1900 boxes and put the outlets in industrial covers and screw them to the boxes easily.Box, https://www.homedepot.com/p/RACO-4-1...-260/205758429Cover,https://www.homedepot.com/p/RACO-4-1...-878/202056914Last edited by danielplace; 07-03-2021 at 10:03 PM.
Reply:Originally Posted by M J DYou would still want a nipple connecting the 2 boxes to prevent wire chafing. You certainly could weld something to keep the boxes from twisting. I think you would need 3/4" or 1" nipples to fit the required wire thru
Reply:Originally Posted by JD1My 50a welder outlet is 20' from my welder so I run a #8 extension cord to it. I'm thinking about getting a plasma cutter and wonder if there's a way to create a dual plug on the end of the cord so the plasma and welder can be plugged in at once. They'll run separately, never at the same time. Sure I can unplug one and plug in the other but was just curious about the possibility.And BTW, are most 220v plasma cutter plugs Nema 6-50P like a welder?
Reply:I built a 4 recepticle tree for my 3 welders and plasma cutter. All on the same breaker and cable.
Reply:I have two welders on this cart so I wired a box on the back of the bottom one so the one on top can plug into it.  This way only one input cord is needed for the two welders. My welder extension cord with two boxes...Sent from my iPhone using Tapatalk:
Reply:Great! It can be done then. If I wind up getting the plasma, I'll do it. I'll probably make it so it plugs in to the existing 6-50R on my extension cord rather than remodeling the cord in case at some point I want to use my cord as it is now.
Reply:The problem is making the splices in the number #6's. You are almost forced to double tap one of them. That is illegal but on a extension cord probably ok and consider it a do what ya gotta do kind of thing.If you have some old SJ cord or can sacrifice what your working on for a little length get some wire from the cord to make your jumpers with. It is fine strand and more flexible copper/covering that say a piece of THHN.
Reply:You dont really need to make a 3 way from the heavy conductors, wire nut 2 number 10 to the 8.
Reply:Originally Posted by SberryYou dont really need to make a 3 way from the heavy conductors, wire nut 2 number 10 to the 8.
Reply:You really can ss long as they are not a 252 class feeder with hi duty and rven then would be a mosyly moot ossue in all but a production fab shop. I dont pwn a vord heavier than a 10.  Basically any time there are multiple recepts the combination mist trip thr breaker on thermal before it overloads the wire they are spliced to.  With really new machines could safely splice 2 to a 10 but its not really legal to wire it that way.  This is to others,, not really danial in particular,,, but with 2 recepts,, neither machine by itself would over heat wire or trip breaker, 2 small macjines could run at once, wont hurt wire or trip and 2 larger machines at same time would trip a bresker before overheating the wire.
Reply:What you cant do is increase the breaker to run multiples, the factory wired machines sre designed for 50.  Certain portion of the equipment relies on the circuit breaker for fault protection the same ss power strips on 120 general use circuits, same ss any ewuipment designed to be connected to a current limited circuit. It doesnt always require that much but depends on breaker for internal fault protection.  Electric range wired on this principle. AC buzzer same way to some extent at least for fault and thermal slightly different.
Reply:Really the only time a breaker protects building wire for thermal is a general use circuit w multiple recepts.  In most,, almost all others the breaker is simply an off on switch which allows enough current to pass to do the work and limits the short circuit.  Not truley thermal protection in the eay its often thought of and commonly portrayed.Thermal is done by applied load and often wire sized up for faults rather than adding additional overcurrent protection.
Reply:The thermal on a power strip isnt really a breaker,,, its a thermal overload and short circuit duty is still provided by breaker.  Cords not thermal protected but fault protected, same as internals of range or the welder especially old buzzers.
Reply:I realize we are talking about a extension cord that will be out in the open where it is easily seen and can really only be loaded while operator is present so maybe some of what I think your trying to say may not pose as much a risk. For wiring that is part of the permanent electric system then you should never be reducing wire sizes midstream to something less than it is fed with for sure.You can normally only do that is like say the larger wire has only been run for voltage drop not to deliver full ampacity like say a 200 foot run of #8 on a 30 amp circuit then reducing to #10 at close to the end before it reaches what it is feeding. Notice no wiring in the run can be less current carrying ampacity than the ampacity of the breaker protecting it except when you start to factor in some of the special rules they have for welder outlets. Those special calculations for welding outlets were written to save cost on large installations of numerous larger welding machines at a distance from the panels where they are trying to save cost on the wire.Personally I believe a 50 amp outlet is best served with the full 50 amps means it needs #6's.
Reply:You dont reduce midstream.  Yes they are for welders, that is kind of the point.  If there was some gain there would be more incentivr to up the wire but there really isnt and other equipment does not come 6 50.   If this was another device we would say there was a co spiracy to sell more wire,, ha but,,,, despite some popular belif the code is really well thought out in this regard and for this allowance.  If it was a problem they would have changed it in the last 90 yrs.
Reply:The owners manuals do account for distance and voltsge drop. The min wire for a buzzer is 12 at near 80 ft. This is allowed on a 50 breaker. No one thinks that is a great idea in real life and i dont do it for 50A and dont use 14 on 30 even though it is legal in some cases. A fussy guy can tell a little difference in wire size with 120V and 14 vs 12 north of 50 ft with machine wide open. Its minor and only fussy testers could tell.     The difference in 12 vs 10 on a buzzer is a pinch. Especially on longer circuits.  Losses for all practical purpose disappear with a number 10 and diminish with larger wire.
Reply:For wiring that is part of the permanent electric system then you should never be reducing wire sizes midstream to something less than it is fed with for sure.
Reply:True electricians seem to often grasp this with some kind of instinct.  I have to be shown,,, I am an installer or wireman more than an electrician and am confused bu more than 3 or 4 wires and sometimes with those. But what I speak to is what the manual calls "qualified" installer in the sense that we are familiar with the code in this aspect and some nema to be able to decipher the language in the instruction manual which can be confusing at best,,,, such as mac breaker of 30 for the new welders which isnt a complete explanation of what it means.   Now,,, this is an opinion,, or I think,,, but a more clear explanation for the small welders so popular now needs a better explain in the manuals due to the diy installs.Last edited by Sberry; 16 Hours Ago at 09:56 AM.www.urkafarms.com