Help Please with Wire / breaker for Arc Welder

[JoeFin]

A 50' run of 10 awg will be fine

40 amps continuous on 10 awg would be 90 C (194 deg F) so I'm "guessing" 50 amps will be way under the ignition point of a wood framed structure.

From past experience the most likely failure points will be at your connections. So if you were to use a grounded 4 11/16 steel box with raised P ring in your wall you would be pretty safe.

That's what I am doing with my welding receptacles in the addition I am building now. That and I bought the 16" bracket arm to go behind the steel box for additional support. Changing plugs on the old box made it flex a lot in the wall and was getting a bit scary

 

[sberry]

If you want to pay the difference for 8 it wont hurt a thing, 2 number 8 and a 10. In a pipe the wire would overheat and short circuit, I am not sure how long it would taker to heat a 10 at 50 continuous load but you wont do it with a welding machine that comes from Lowes. The only machine that comes with a 50 plug that calls for an 8 is the MM252. My Lincoln 255 allows a 10. The 252 has near 300A max output and at rated something like a 60% duty cycle. It will ruin the factory gun in short order. Takes a special gas and 045 wire to crank it that hard. Also use a standard 4 inch deep box so standard covers fit. The device will fit in a 2/4 deep, the 4 x4 is a lot easier when dealing with larger number 6 wire.

From past experience the most likely failure points will be at your connections.

From a code perspective this may be an issue. A welder plug lists the wire size on it, while a 211 with 14 may be legal the connection to the recept isn't. I don't recall about all of them but seems I have seen some recepts list number 10 as a minimum. and that's a good reason all its own to up size the wire in some cases.

 

[sberry]

The only reason I harp on this is that I can remember the learning curve, how I thought about it then and now and the real things I didn't know and understand. The forums have been a Godsend to grounding. They have pounded code and preached follow the directions till you understand it etc.
When I was learning all the fittings I felt like I invented odd design and I can walk to the parts counter and fool the guy in to thinking I am an electrician but I learned slow and its takin me a while to start to simplify, speed and cheapen the process and its easy to over think during design, mostly a waste of pipe and wire all to run a battery charger or grinder once in a while.

The net result is in hindsight could easily run it all with 2 circuits vs the 4 I installed just in case, should have run another pipe at a later date to tailor it all vs trying to outthink it all with infitismal losses in intermitant use which still falls a class above a code standard. ha. A light circuit, an outlet to a 50 ft cord would have done the same thing. Use a common box with common fittings and have some you can use the extras on when its all over.

If a guy is willing to run a pipe he is interested in doing it right, the op actually was coherent about the need, intended use and the duty cycle, an arc welder set up for maint work, if worse came to worse can even add more wire to the same pipe in the future.

He has to buy the wire the question is,,, is this machine likely to be replaced by one dedicated to it that may require larger service? If there was a realistic chance I would have an bunch of Amish I was paying piece work to in a stove or trailer factory then the difference in change could buy some zip especially in bundled wire etc, hot factory and long distance.

 

[sberry]

But, the home owner, small biz hobby guy does not need to stay awake wondering if the 10 romex to that outlet is going to combust in the middle of the night or any other time if the lugs are secure in the recept and in the breaker while hooked to a buzzer. Even less to a 200A mig, only draws half the buzzer.

 

[sberry]

I wouldnt5 have much use for a buzzer anyway if I was Joe Hobby or maint type but for rare use. Unplug the 200 Mig you need if you don't have for the occasion, same circuit for both machines.
In some cases the high cost of wire can off set new machine cost. A common AC/DC buzzer is fantastic, it cost 500 maybe if we got to wire it a hundred ft of 6 and big pipe etc the cost makes an 800$ Maxstar look good. In reality the buzzer could do this with 3 sizes smaller wire which would still be one above its minimum which reduces cost especially if the intent is for standby use. A Max might be able to do some work at 100 ft of 120 cord, will run wide open at 240 200 ft of 12. This doesn't include the potential savings from secondary leads.

 

[JoeFin]

In some cases the high cost of wire can off set new machine cost.

And that is what I believe is forcing the manufactures to push the absolute bare minimum NEC standards - even to the point of being misleading

MARKETING

They know the lower they state the circuit requirements the more they entice the Homeshop/Hobby type buyers and hence good for sales

1 of the guys over at Practical Machinist forum was part of the engineering group that developed the Ford Ranger 4x4 for Ford - You should have heard all the concessions the engineers had to make for the marketing department. 1 was they originally designed it with Independent Front Suspension - but Oh No - marketing couldn't have that. The Ford Ranger had to have the hallmark of Ford Truck suspension - the I Beam suspension

 

[sberry]

Yes but some of this principle has been there for a long time, ever since they made the welder. Hundreds of thousands of these installed from range fuses in entrance panels in garages. Feed thru fed a 1 armed bandit from 60 mains and the welder hooked to the range side with a 10 cable. Now voltage has went up, makes them run even better. Probably around 40A actual on a buzzer now.

 

[sberry]

My old service was old and marginal but with new had to turn the welder down 5. 50 yr newer ****** on the pole.