Welder Wire Size ... Lincoln 255XT

[ducatithunder]

I was reading through my manual today regarding feeder wire size. Before I start pulling the wire I wanted to confirm my thoughts with some of the forum electricians.

Background info ... My receptacles are all under 100ft from the panel. This is the biggest welder in the lot so the others should be covered it this is good. The plug on the machine is a 6-50 so Im using 6-50R plugs.

Just wanted to confirm that I am reading this right. Im running single phase 230V.The 40% Duty Cycle on this machine is 250 @ 52Amps with the 115v loaded 120V aux loaded.

From the chart they list 75Deg wire @ 10AWG for under 100ft. Im running NM wire so in order to cover the amp draw on the 60Deg chart I should be using 6AWG correct? I doubt Ill ever hit the DC on this machine but wanted to make sure it was right the first time.

Ive attached a picture of the manual below. Thanks.

 

[pattenp]

#8 NM-b can be used.

 

[sberry]

It will run dandy on 8.

 

[ducatithunder]

#8 NM-b can be used.

/
Is there a special reason for that based on DC or usage? All the charts say #8 is rated for max 40 Amps. Did I overlook something? Thanks.

 

[sberry]

The welder is duty cycle rated. You could save some alum wire, if there was a chance I wanted any additional circuits in that neighborhood mightvpull a 2 alum cable and hook a 6 space panel on the end of it. Makes for a super welder circuit.

 

[Bert_]

/
Is there a special reason for that based on DC or usage? All the charts say #8 is rated for max 40 Amps. Did I overlook something? Thanks.

Welder has 40% duty at max amps.

 

[ducatithunder]

Ok. Figured that might be the reason. So I would use a 40Amp breaker for the runs then since the wire is only rated for that? I have the 6/2 already. I guess I could use 8/2. I was running 8/2 for the compressor circuit as its 5HP and to cover the NEC 125%.

I have a 4 receptacles to cover the 28x46 garage. 2 circuits run in parallel on opposite sides of the shop. The TIG is a 200 Dynasty and I will get a plasma later next year either a 675 or 875 Miller Spectrum. I will have to see if the plasma will be good with 8/2. Thanks.

 

[nadogail]

I used #8 for my AC/DC Stickmate

 

[nadogail]

Because of the rules for welder circuits the factory installed power cord on my AC/DC Stickmate is 12 gauge wire.

 

[sberry]

Something else to consider with the full size machines. The wire size is at rated load. If this used ant less than a trailer assembly line it won't have the guts wrung out all day. A 250 running 035 C25 in a common garage will run 10. The 8 gives it a little boost.

 

[ducatithunder]

Something else to consider with the full size machines. The wire size is at rated load. If this used ant less than a trailer assembly line it won't have the guts wrung out all day. A 250 running 035 C25 in a common garage will run 10. The 8 gives it a little boost.

Understood. That is what Im picking up from the last few post. I just dont want to have any regret or issues down the road. If only one plug was going to be wired for this machine I wouldnt hesitate, but this is a larger ring circuit running around the garage. Ill have to look at the plasma and check the DC and Input Amperage. I

Im not running a commercial shop as you stated. I doubt I will hit the 60% DC for normal use.

So I can still use the 6-50R on the outlets but will use 40amp breaker to protect the circuit if 8/2 is used.

 

[Bert_]

Don't undersize the breaker. If it has a 50A plug it can use a 50A breaker. That machine would probably trip a 40A running wide open.

 

[ducatithunder]

Don't undersize the breaker. If it has a 50A plug it can use a 50A breaker. That machine would probably trip a 40A running wide open.

Thats the confusion ... if the branch wire were 8/2 NM isnt the max amperage 40A? Are you saying its ok to run the 8/2 and have a 50Amp breaker protecting it? Or are you saying go 6/2 and 50amp breaker for a true 50amp circuit?

Correct if I actually ran it at 40% DC it would draw 52 amps off the spec. Im not sure Ill ever hit it needing to weld @ 250A at any given time. This is a DC and AC Mig machine so it can run a aluminum spool gun. That may be the only time it would be cranked all the way up.

 

[wyliesdiesels]

since this is for a welder circuit, the NEC allows a mismatch on the wire/breaker size.

the 40a for #8 NM-B is for general use circuits..

 

[ducatithunder]

Ok ... learned something new today. So 50A breaker, 6-50R Receptacle and Plug, and 8/2 wire is kosher for welding applications. Thanks for the clarification.

 

[Bert_]

The machine needs 50A. But it can only do it for 4 minutes out of 10. It can't overheat the wire.

Lots of stick transformer machines can run #10 on 50A.

#8 on 50A will run any machine you could want

 

[ducatithunder]

The machine needs 50A. But it can only do it for 4 minutes out of 10. It can't overheat the wire.

Lots of stick transformer machines can run #10 on 50A.

#8 on 50A will run any machine you could want

Thanks I just read through NEC 630. Thanks for the advice. Makes alot more sense now that I can see the math and reasoning behind it.

 

[Noltz]

Strictly curious; Why would the code allow for a mismatch on the wire size based on a non-hardwired load? Or in other words, would it not be a serious issue if someone plugged in say a bigger welder, a lathe or something more continuous duty? Space heater even?

 

[sberry]

It's because those other machines do not come with a plug and cord.

 

[TractorJeff]

Based on Posts #7 and #11, I personally would run the "2 in Parallel or Ring" Welder Circuits with 6ga. Reasoning is that there may come a time when a Helper (Son, Daughter or Neighbor) is running a second device.

 

[alfredeneuman]

"2 in Parallel or Ring"

Please define this term.

 

[ducatithunder]

Please define this term.

Not really a term. I’m running the perimeter of the shop with a single 230v circuit. All the outlets will be wired in parallel. I don’t plan on using more the one outlet at a time. Worst case as stated above I run 6/2 or just break it into two separate 50 amp circuits.


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[alfredeneuman]

Not really a term. I’m running the perimeter of the shop with a single 230v circuit. All the outlets will be wired in parallel. I don’t plan on using more the one outlet at a time. Worst case as stated above I run 6/2 or just break it into two separate 50 amp circuits.

OK I understand now. All outlets have to be wired in parallel.
Parallel conductors are a different thing; 2 wires in parallel hooked up to a single equipment from 1 source (breaker or fuses), and the minimum size to do this is 1/0.
Ring circuits run from the breaker to loads, and back to the breaker in separate lines.

I don't know of any 50A breakers with lugs listed for 2-#6s though.

 

[Mr_fixit]

That machine probably has an 8/3 cord.

 

[pattenp]

To throw in a kink, if you are subject to the IRBC (International Residential Building Code), a circuit greater than 20A is not to have multiple receptacles. In other words 30A and up is to be only a single dedicated receptacle on the circuit.

 

[ducatithunder]

Understood. Not that is makes it correct but I have seen plenty of guys do this. I am doing the same more for convenience on the one circuit. 3 outlets total ... one on each wall strategically placed. This will be a one machine circuit. I will have another dedicated outlet by the bench for welding. That makes for 2 separate welding circuits. I have a 25ft extension from when I was operating this at my house. Looking to not have to use it anymore unless Im going outside. There will be other 230v circuits that will be dedicated the lathe and future mill location. Those will not have to be nearly as beefy as this welding circuit. Thanks!

 

[ducatithunder]

That machine probably has an 8/3 cord.

It does.

 

[sberry]

I have a red 255, older one and I think it has 8 and lists 10 wire in the manual, but remember when its like that its single circuit in pipe. They even put that cord on a bunch of little machines, for exactly why I am not sure and when they change it not sure. Some of those years I am not sure why they did some of the things they did and while I own Lincolns was never familiar with the product line like the Hobart and some of the blue.

 

[sberry]

Not every lathe and mill runs from 240. But having a couple outlets on the same circuit in a garage wouldnt bother me a lot. As long as it recepts, wire and ocpd all matched up but most garage small shate probably run from 20???

 

[ducatithunder]

Not every lathe and mill runs from 240. But having a couple outlets on the same circuit in a garage wouldnt bother me a lot. As long as it recepts, wire and ocpd all matched up but most garage small shate probably run from 20???

Im running a three phase Logan on a Fdrive. Im looking for a 2j Bridgeport that will sit next to the lathe. Most of those are 1-1/2 HP to 2HP motors. I should be able to run on a 30A 240V dedicated circuit with a 3HP VFD.

 

[sberry]

3 hp will run from 10 cable. So will the feeder if you are not wringing it's guts out.

 

[ducatithunder]

3 hp will run from 10 cable. So will the feeder if you are not wringing it's guts out.

That is my plan. Other then the compressor and welding circuits the remainder will be 30amp 10/2 runs for the car lifts and lathe and mill runs.