Wiring welders

Sberry

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There needs to be a continuous thread on this. A lot of misunderstanding. This is a start. Seems to be confusion on cord sizing. Basically all 240V machines come cord and plug come 6-50. They need to be designed to be able to safely plug in to a common 50A welder circuit. The 240 only,,, not the dvi9 come 12 cord or better. The owners manuals are very confusing to someone not been schooled on it and the new imports even more so as they dont come with a guide, they seem to leave it to the installer to extrapolate the required wire size.
 

Sberry

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At this point unless there is a specific need we should keep in mind this is for factory supplied cord and plug machines. Its worth noting that the minimum sizes are for single circuit in pipe, for cords and cables its up 1. But almost NONE of them require 6 and certainly not cords and not in home shops. Only machines that even require full wire are 251+ migs. Some have 60% duty and very high outputs but this is special gas, large wires and even non stock guns.
 

Sberry

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Brethren, Mi
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Contrary to some belief number 10 can be loaded higher than 30A, actually 60 is the limit, 50 for number 12 and 30 for 14,,,, this is for welders and the allowed over current protection within some equipment. The breaker in these types of circuits DOES NOT protect the building wire for thermal,,, the applied load does. I am going to include minor disclaimers such as most, many etc vs always because there can be some exceptions but they really not relevant to this discussion.
The breaker protecting wire is for general use circuits where there are multiple receptacles where the end user can overload it by plugging in more equipment on the same circuit. The breaker is there for short circuit and machines are designed to be plugged in to a specific current limited circuit. 60,,,, 80 A breakers not allowed for this no matter what the wire size is,,, if it has a 50 plug they need to be on 50 or less.
 
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Sberry

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Now,,,, before we go much farther and I need to resist the urge to say,,, you dont know wtf you talking about,,, I have found,,, I have never been right about what " think" the code should be or some reason they got it wrong and if you are inspired by an original or better idea you are not,,, they already thought about it, already considered it, its not a problem or is and its why they dont ask us to be on the code board.
Also "I did it this way" does NOT mean its correct, often throws other aspects of the code out of compliance and cause it works when you flip the switch doesnt mean its right and simply sizing wire up a couple does not make oit safer and other problems go away. Proper size is different than bigger is always better. While the wire size in the code is "minimum" it does not mean its not adequate, these been in the book a long time, things got a lot better, coatings better, voltage up 10% since they size a lot of wire reducing the current.
Its worth noting that some allow the same wire at 208 as 240, huge difference in current. If its good at 208 way better at higher.
 

PILOON

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If U know the gauge of the welder cord, anything above that should be OK as long as the distance is within reason. (like 30-40 ft and not 100+}
 

Sberry

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The fact that the incoming wire is 1 size larger is the thermal protection for it.
It is a co.mon statement that comes up in most threads that,,,, the breaker is only there to protect the building wire from overheating. This is only true where too many appliances can be plugged in to the same circuit, might be able make that case for a motor ho.e circuit and for service entrance. Most other circuits it's simply a switch that provides short circuit protection for that wire and connected equipment.
 

Sberry

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Brethren, Mi
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Its a somewhat difficult concept to grasp that the wire sizing IS the thermal protection and not the breaker.
 
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