Lincoln 225 AC/DC circuit requirements

[_RaT_]

Welders are unlike other devices that you wire based on breaker/wire sizes. When you go to the code book, it shows you how to figure wire size based on the welders DUTY CYCLE. A 100% duty cycle welder will require the wire be protected by a breaker no larger then the maximum current carrying ability as established in the NEC wire chart. From there however, you can derate it, that is, provide a larger breaker then the wire would normally be sized for. The logic is the wire will easily handle the larger current for a short duration. That circuit will be dedicated though for a welder. You see this also in home uses for AC units where a 40 amp breaker may feed a #10 wire when used in a dedicated AC circuit. The reason is because of the high compressor start up demand and relatively low operating current demand. On the AC unit you will see minimum circuit size and maximum fuse size, this is your guide to sizing the wire adequately. My AC unit has a brief start up current of 102 amps yet runs at 17 amps. A #10 wire is all that feeds it. This is per code in my area.

PS - As I remember, a 20% duty cycle allows you to weld 2 minutes out of every 10 minutes. If you continually exceed this duty cycle, it will overheat the transformer, ask me how I know this. /forums/images/graemlins/grin.gif

 

[Inspector507]

Jim
Here's how Lincoln recommends to connect it
AC/DC 225/125 manual

It contains specs on the circuit protection size, wire size and receptacle required. When I listed how the NEC says it can be done (which is identical to Lincoln's maual) yes, there was some "discussion" about it which I won't get into again. If you want to follow how the manufacturer recommends doing it, that's up to you. If you decide to go over and above, that's your choice too.

 

[Highbeam]

I was burning lbs of rod per day on my last project. I got to wondering about duty cycle on my AC225. Does the welder need to be turned on with the fan running during resting periods? Or can I shut it off since I am not fond of being shocked. I also just weld like a mad man without regard to the duty cycle and notice no degradation in welder performance. What is supposed t ohappen when you exceed the duty cycle on a welder like the AC225? If I kill the welder (bought for 0$) then I will have a great oppurtunity to go AC/DC.

Myself, I used the wire sized to handle the full 50 amp breaker current. The run was short and cheap. Plus I don't want to be liable if the next owner plugs a water heater into it or uses the plug with a generator to backfeed the house. If we were talking about hundreds of doolars of extra wire then I might consider undersizing.

 

[_RaT_]

I think the "duty cycle" wire sizing is more for those with existing situations where running new wire is either not easily done or their needs are not really that demanding. I am with you, if I am running a new wire anyway, I'm going to opt for a larger wire, maybe even larger then the 50 amp/20% duty cycle circuit that the Lincoln requires since you never know what you may end up with. ( I have the older version Lincoln that goes to 180A AC only). Its not unusual to have a MIG unit that takes a 70 amp 240V circuit, at least, not the ones I was looking at. You can always oversize the wire. The duty cycle would require the unit to be on if it uses a fan for cooling.

 

[PineRidge]

<font color="blue"> Myself, I used the wire sized to handle the full 50 amp breaker current. The run was short and cheap. Plus I don't want to be liable if the next owner plugs a water heater into it or uses the plug with a generator to backfeed the house. If we were talking about hundreds of doolars of extra wire then I might consider undersizing.

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Highbeam we sized our wire the same way. Don't know what the duty cycle is for the Lincoln Tombstone, all I do is weld until I'm finished then let the machine idle with the fan running to make sure its cool. Been doing it like this for years, if and when the welder bites the dust then I'll upgrade anyway.

 

[_RaT_]

I think the Lincoln has it stated right on the front of the box. I thought it was about 20%. It really does not matter because it is very unlikely you will weld continuously at full 225 amp AC for much more then about 30 second spurts anyway. I have seen the arc just start falling apart on MIG machines when they get to hot, eventually triggering the thermistor to shut the unit down. I have welded at 135 amps on my Lincoln 180 for 30 minutes at a time. The transformer was hot, the #10 AWG 60' long extension cord on the 50 amp breaker was not even slightly warm. It gives you an idea of what these wires can handle.