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  #21  
Old 02-11-2020, 11:47 AM
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Maybe you have gotten lucky and the manufacturer designed it with a line contactor/relay to handle the load, not the switch.
Nema or code says all welders will have a switch that disconnects all ungrounded conductors.
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  #22  
Old 02-11-2020, 12:47 PM
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Without power factor caps, a inverter stick welder will pull 25 amps of 120 volts at 90 amps.. Just that a good dedicated 20 amp circuit will handle it for quite sometime. Plasma cutters ,and wire-feeds are not that far behind in pulling all you can get out of a 20 amp breaker. Not uncommon on top brands/ cheap brands,, Put a real quality amp gauge on your input power, and you will find out..
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  #23  
Old 02-11-2020, 12:54 PM
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Originally Posted by Scott V View Post
Without power factor caps, a inverter stick welder will pull 25 amps of 120 volts at 90 amps.. Just that a good dedicated 20 amp circuit will handle it for quite sometime. Plasma cutters ,and wire-feeds are not that far behind in pulling all you can get out of a 20 amp breaker. Not uncommon on top brands/ cheap brands,, Put a real quality amp gauge on your input power, and you will find out..
WoW !

My leetle Lincoln lunchbox (older model) sp-100 never tripped a 20 amp breaker.
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  #24  
Old 02-11-2020, 01:38 PM
nelstomlinson nelstomlinson is offline
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I would replace the plug with a NEMA 5-something, and put in an outlet to match. NEC allows you to derate a welding circuit, so you can use a smaller gauge wire if you want. I prefer to use the full size wire for the breaker, so I have to option to repurpose the circuit later, for something like an air compressor.

So, I would run something like 4 AWG, three conductor with ground, and protect it with a 50A breaker. Three conductor gives you the option to make it 240V later, and 4AWG gives you the option to put something NOT a welder on the circuit. You could even use a 50A, 2 pole breaker, and just don't use one of the poles. Safe off both ends of the conductor you don't use. You probably can't find a 50A, single pole breaker in Home Depot, anyway.

The cord is too small to handle a steady load of 50A, but as others said, the welder will probably melt before the cord does. Use it 'til it fails, keep it away from flammables so it doesn't burn your shop down, and start saving for something that isn't made in China.
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  #25  
Old 02-11-2020, 02:10 PM
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Originally Posted by digger doug View Post
WoW !

My leetle Lincoln lunchbox (older model) sp-100 never tripped a 20 amp breaker.
It's on many welders.
Here is my older Thermal dynamics PeeWee 85s. These were one of the most expensive 120 volt only stick welders ever built by Sanrex. If you look at the amp draw, then the 15 amp plug. Pretty standard overall now.
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  #26  
Old 02-11-2020, 02:27 PM
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It's on many welders.
Here is my older Thermal dynamics PeeWee 85s. These were one of the most expensive 120 volt only stick welders ever built by Sanrex. If you look at the amp draw, then the 15 amp plug. Pretty standard overall now.
Yabbut !
What's all this hype about how inverter supplies (welders & plasma cutters)
draw soooo much less current ?
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  #27  
Old 02-11-2020, 02:30 PM
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NEC allows you to derate a welding circuit, so you can use a smaller gauge wire if you want. I prefer to use the full size wire for the breaker, so
You must use a full size wire and breaker for circuits other than a welder. What I mean by that is it would mean a welder outlet. Outlets other than that need to match. You can put a 50A on a 10 to an air comp if its hard wired,,, hp rated outlets really only rated for 3 hp so the code forces the outlet out of the way for these circumstances. (with common equipment) The code assumes the installer did this correctly all along the way to the outlet.
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  #28  
Old 02-11-2020, 05:36 PM
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Originally Posted by digger doug View Post
Yabbut !
What's all this hype about how inverter supplies (welders & plasma cutters)
draw soooo much less current ?
They can in overall usage. The Klutch 120 volt Mig will flat out blow away any 120 volt Transformer machine on wetting out 3/16 MS running off the same outlet. Stick 120 transformer welders just suck hind tit too.. The OCV is generally way to low to run quality rods.. 120 volt plasma cutters pretty much kick the crap out of any transformer based unit. Performance is not just amp draw.. You might see a across the board 25 % improvement if you put a amp gauge on both sides of the machine..

Use to be, cruising along much less energy used, and the closer to the top end of the power scale, a transformer and inverter start to narrow the gap..

It's just the inverter arc is so much more adaptable, you can do way more with it.. AC/DC tigs come to mind. My Lorch 220i will weld AC output comparable to a 300 amp tig easy. Time on DC, and adjustable freq favors the inverter. Probably drawing 1/3 the input power while wetting the same thickness of aluminum. Although this is the very top as far as tigs go,and it's amps kick butt on any process.


I still like old school little Wire welders.. The little Lincoln ones like the 140 do a pretty good job of wetting out the weld bead..
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