My buddy has got a welder and while I originally thought he was getting something smaller I do need something welded and would help him out regardless.anyways I've shown the nameplate to a couple electricians and have gotten mixed responses hopefully someone can clear this up. What size breaker to run this thing ? Here's from the manualhttps://imgur.com/a/yfiEN
Running buddy's welder
- Thread starter 420313
- Start date
- Status
- Occupation
- Licensed Electrician
Welcome to the forum.
Someone here can help you but we need to know what is on the nameplate of the welder. Even better you can take a stab at the answer first and we can check your work.
Someone here can help you but we need to know what is on the nameplate of the welder. Even better you can take a stab at the answer first and we can check your work.
JFletcher
Senior Member
- Location
- Williamsburg, VA
JFletcher
Senior Member
- Location
- Williamsburg, VA
Welcome to the forum. Welder breakers have a lot of leeway, especially if you figure a different duty cycle than the mfg table. What is the voltage of your power supply? That will determine the breaker size. Also note that the wire size given will be larger if you wire it with NM cable (Romex). that chart reads 'based on 1990 NEC'; most states now are on the 2014 NEC.
You're pretty much stuck with 125A max as I dont believe they make larger breakers than that for the avg residential panel.
You're pretty much stuck with 125A max as I dont believe they make larger breakers than that for the avg residential panel.
- Location
- Massachusetts
To add to that, unless the guy is doing production welding of military tanks and ships 50~60 amps input will be enough.
junkhound
Senior Member
- Location
- Renton, WA
- Occupation
- EE, power electronics specialty
+1; Fer sure.
The welder in my barn is 230A, fed from 50A breaker at service thru 200 ft of 8awg. Also a 50 A QO breaker in the barn.
Once in a great while the 50 A QO breaker will trip, but only if I've been welding relatively heavy stuff for over 1/2 hour with 5/32" 7018 rod. Will trip using 3/16" 7014 also
, or leaving connected to a piece of 1/2" steel rod for a few minutes to 'heat treat' the rod.Warning, do not do this, not per NEC :happyno: -- 220 outlet from a separate feeder to service on 12 AWG, 20 amp, double ended male plugs on 'cheater cord' tying the feeders in parallel, never trip even with the 3/16" rod, welder itself limits the current.
So, if you do need to weld up your old Sherman tank tracks, a 100 A breaker and 4 AWG on a long run will do you just fine and never trip in heavy 350A welder usage.
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HI thanks his sub panel in the garage is 100a... looked at it yesterday the sub panel is actually coming from the meter where it seems to be double tapped ...the #2 se cable is also unsupported the whole run >.< never heard of having 2 mains seems wrong to me *shrug*. OK so I remember opening up the code book wich I'm not too familiar with and coming up with #4 or #2 copper but if his panel is only 100 amps I guess I'm just going to go with the biggest breaker I can but I guess then using #4 or #2 would be unesccesary?
Okay yea. Don't quite understand the last part maybe that's a good thing lol okay so I know unsure how to rate the wire now for whatever breaker I choose+1; Fer sure.
The welder in my barn is 230A, fed from 50A breaker at service thru 200 ft of 8awg. Also a 50 A QO breaker in the barn.
Once in a great while the 50 A QO breaker will trip, but only if I've been welding relatively heavy stuff for over 1/2 hour with 5/32" 7018 rod. Will trip using 3/16" 7014 also
Warning, do not do this, not per NEC :happyno: -- 220 outlet from a separate feeder to service on 12 AWG, 20 amp, double ended male plugs on 'cheater cord' tying the feeders in parallel, never trip even with the 3/16" rod, welder itself limits the current.
So, if you do need to weld up your old Sherman tank tracks, a 100 A breaker and 4 AWG on a long run will do you just fine and never trip in heavy 350A welder usage.
kwired
Electron manager
- Location
- NE Nebraska
Run a general purpose 50 amp circuit to a 6-50 receptacle and you will likely not have any problems. If your friend is building ships or tanks, chances are he will find that he needs a bigger service to his home.
OK then the wire should just be rated for 50 amps then?
JFletcher
Senior Member
- Location
- Williamsburg, VA
Yep.
rambojoe
Senior Member
- Location
- phoenix az
- Occupation
- Wireman
is the welder new or used? if used verify what voltage its tapped for in the input wiring box, although it looks like it wont fry evn if you try. and even better, if there is a power cord on it with prongs, take a pic of the plug and post what voltage it says. I promise you SOMETIMES welder voltages and nemas can be "rigged"..... guilty oh btw if new, id feel safe confirming factory wiring/voltage via the plug alone. point is if used, ask questions!
oh btw if new, id feel safe confirming factory wiring/voltage via the plug alone. point is if used, ask questions!didn't think of that I will investigate. You're talking about the internal transformer? What I thought was his sub panel is actually being double tapped with other panel and se cable running all the way to garage from basement!! OK so as I calculated from the manual I debated the wire with duty cycle multiplier so a if I used a 100 amps breaker I could use wire rated at 100 amps but I can debate that with the duty cycle multiplier?I do not have the code book on me atm.is the welder new or used? if used verify what voltage its tapped for in the input wiring box, although it looks like it wont fry evn if you try. and even better, if there is a power cord on it with prongs, take a pic of the plug and post what voltage it says. I promise you SOMETIMES welder voltages and nemas can be "rigged"..... guilty
rambojoe
Senior Member
- Location
- phoenix az
- Occupation
- Wireman
one thing at a time! overkill (rather too much) can present connection problems some times. yes, the internal tranny at the point of connection- regardless of what plug or color wire is in the whip... if used, or new, verify the voltage. and screw the link, just post the volts and amps stamped on the unit. or plug. or whip.... always set things up for the highest voltage you have to provide. that way its safer because its amps that kill not volts. (ok ol timers, that's funny. but I'm kidding)
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