What size wire for welder circuit?

[Gary_in_Indiana]

I have a new Hobart 175 welder which requires 220V service. Of course, Hobart doesn't include this info in their manual so I come to TBN, the font of all wisdom. /w3tcompact/icons/smile.gif

What size breaker and what size wire should I use for this run. It's probably going to be approximately 100' from the breaker box.

Additionally, I'd like to run a second outlet for the same welder off the first so I can use the welder at the other side of the shop more easily. Are there any problems with that given only one will be in use at any given time?

 

[gerard]

1. No problem running two outlets off same circuit.
2. Check on the welder - it will tell you what the amp draw is at 100% duty. Probably 50 amps. You basically need the same circuit as you would put in for an electric range. I THINK you need #4 and at least a 50 amp breaker, 3 wire + ground. Someone here will give you a definitive answer if the # 4 is wrong or you can just go to an electrical supply, tell them what your doing and they'll let you know what size wire you'll need.

 

[JATO_RaT]

The chances your welder is a 100% duty cycle is pretty slim, most homeowners types are about 20%. The wire size for welders is determined not only by maximum current draw, but duty cycle as well. You will find that a number 10 or 10AWG wire may work with a 180 amp welder at 20% duty cycle, but it limits you to that specific welder. Better to go oversize with anticipation that a replacement welder could surpass what you have now. To be safe, given the information you gave to us, a #6 wire may easily work. None of this takes into consideration the voltage drop. You can always run a larger wire size even if the breaker amperage is much smaller then wires safe current capacity. As Gerad said, you can run several outlets, but with welders, the duty cycle really makes that more confusing. A subpanel may be your best option. Rat....

 

[bgott]

http://www.elec-toolbox.com/

Hit this site, go to "calculators". I used calculator #1, inputted 50 amps and a hundred feet and came up with #6 copper.

 

[wroughtn_harv]

Morning Brad,

That recommendation for number six jives with my practical experience. Two different homes I've lived in have had detached garages. In both of these I've ran number six wires to a subpanel in the garage off of a fifty amp breaker at the main panel.

I've picked up two one hundred and ten circuits off the subpanel, one off each leg. One for lights and the other for plugs. And then of course a welder's plug for the welders and other two twenty stuff.

Ten years ago when I moved into the shop I have now they put me in a welder plug by the front door. I have my three hundred amp Miller Dialarc sitting there. But I cut in a twenty foot pigtail behind that plug, three number three's and put another welder plug on it. Everything that I have that runs off two twenty I plug into the welder plug. And since I can only use one tool at a time it works great.

Yesterday it was a pain changing over between the plasma and the new Panasonic mig as I went back and forth. But that's life in the city when you're so close to the country.

But this system gives me great flexibility. The Little Giant power hammer with it's three horse motor has a welder plug on it to plug into the pigtail. So does the spa blower that feeds the sand blasting hood. And of course the two migs and the little plasma also have the welder plug on them.

The only time I've blown the breaker was when the breaker itself went south. But again this system works only when you have one man using one tool at a time.

 

[bgott]

I'm fixin' to add a 50 amp breaker out in my carport. Climbing over top of the dryer to plug in the welder sucks! Next project is to get HL+P to come back out and finish redoing their neutrals. They replaced the one at the service entrance but the 12 amp window A/C is still dimming the he11 out of the lights. It can be one frustrating experience striking an arc with a funky neutral and I'm tired of fighting it, not to mention the potential for damage to my electronics.

 

[cisco]

Yeah, there won't be a 100% duty cycle, and #8 over 100 feet will probably suffice if it's just basic home welding and lights (#10 - nope, a friend has such, and his lights dim when he uses the welder). That said, why skirt the limits? Use #6, and there is no way, under most circumstances for home garage type welding, including "window" air conditioning and the like, that you'll overly stress the system.

 

[Gary_in_Indiana]

Kudos once again to my local female Tractor Supply Co. store manager. One call to her got me the toll free number of the Hobart distributor in Kansas City who was an absolute wealth of information and couldn't have been more helpful.

The Hobart 175 only draws 19.5 amps maximum. Apparently that's one of it's big selling points. Also, it only needs one hot lead for each half of the breaker and the single, unshielded ground with no "neutral" wire (the white gets marked black and goes to one half of the breaker). Normally, that amp draw would indicate 12/2 but, given the length of the run, he recommended I go with 10/2 to avoid any voltage drop and hence also avoid any possible problems operating at the welder's maximum output level.

Also, he recommended a dual 30 amp breaker, a couple of which I just happen to have anyhow. I bought a 250' roll of 10/2. I'm estimating 100' to a junction box where I will make runs to outlets of 10', 60' and one last run to a third wall as far as my remaining 10/2 will take me. I figure the wire is paid for so I may as well use it and put in three outlets on three walls. /w3tcompact/icons/smile.gif

Doing it this way runs a little bit different than my normal method of overbuilding and over doing everything but since I don't even know how to weld and haven't yet assembled the welder I figure I'm quite a ways away from worrying about my SECOND welder. If I'm wrong it only means I make another electrical run. Now, if this were in a house or finished garage it would be one thing, but with exposed trusses in a barn I don't look at that as something particularly daunting if it does come up.