Welder circuit

[chevynut]

I have been using a Miller Synchrowave 180 TIG welder in my shop on a 50 amp 220V circuit. I have wired my new shop with a 50 amp circuit using 6/2 cable with ground, per the inspector's instructions. I asked about a 6/3 with ground cable, and he said I didn't need it. He said it's only for ranges and devices like that that needed 110V as well.

A friend wants to sell me a 250A Hobart TIG welder and he says I need a 100 amp breaker to supply it. That seems excessive, but he said he has tried to run it on a dryer circuit and it kicked the breaker all the time. He said it was due to the high frequency start on the welder, which doesn't make a lot of sense to me. The welder also has a coolant pump that plugs into an outlet on the welder.

First, I thought dryers were typically on a 30 Amp breaker, not 50 amp.

The welder itself only has a 8/3 cable coming into it, just like my 180 Synchrowave. That size wire is way too small for either a 50A or 100A breaker. Why are they so small?

I assume the coolant pump runs on 220V too...does that make sense? I would think it would need a neutral wire if it ran on 110V. If I add cooling to my 180A welder, it looks like I would need to plug it into 110V. My welder doesn't have an outlet on it. Does it need a separate wire?

Any idea what size breaker this Hobart welder really should run on? I have a hard time believing it would take 100 Amps. I don't want to re-wire my new shop if I don't have to. Should I add a neutral wire to the existing cable I've already run? In other words, should I replace the 6/2 cable with 6/3 cable?

[Rick_L]

I think the logic you stated about the 6/2 vs. 6/3 wire is correct. You shouldn't need to connect the neutral wire to anything, so why run one from the breaker box? Unless the coolant pump or something like that runs off 110V.

I think you're right on the dryer, but it could be 40A also. If I remember correctly, there are different plugs/receptacles for 30/40/50A circuits.

Miller/Hobart should be able to advise you on the input current for the welder. Obviously there's some overhead, but the machine shouldn't be drawing a lot of current unless you're welding with a lot of current. I would also check to be sure that it's a single phase machine, not 3 phase.

[NickP]

My Miller 250 Amp TIG runs fine on 50amp breaker. It also has two 110 outlets - it's on 6/2. My welder didn't come with any lead, I did my own 6/2 lead.

[JT56]

Yes dryers are on a 30 amp circuit. 50 amp is used for range.

[chevynut]

Nick, how do you get 110V from your welder from a 6/2 wire? You have two 110 volt legs and a ground to the welder. Don't you need a neutral to do that?

Rick, it's a single phase welder, but it can be wired for 3-phase. He's used it a lot on a regular 220V line. The Miller coolant system that I've looked at for my 180SD runs off of 110V. Seems like I should need a neutral for that, but Nick says he doesn't have one.

Thanks for the reassurance. I guess I'm not sure I'm going to buy this Hobart. He's going to sell me a mill, slip roll, and a stomp shear too, and they are really priority over the welder since I already have one. He wants to be able to use the stuff once in a while so he's selling it to me cheap and I don't have to pay him for a while.

[Rick_L]

What are your thoughts on what you get from that welder vs. your current one?

Seems that for automotive type work, the only advantage of that unit would be that you could weld 1/4" aluminum more readily than your current unit. Or do you occasionally need 2 machines? (You'd have to wire for that too.)

I know it's not part of the current opportunity, but have you looked at inverter machines? I bought a relatively small one, and it's really nice.

[chevynut]

Rick, the main advantage of this TIG is that it has a cooling unit, and LONG leads. I can set it in my shop and leave it in one place. My current machine does all I need it to do, but it gets REALLY hot when welding a lot...and we do that. And it only has about 15 foot leads so we have to roll it around. I use an extension cord with it. Plus I think I can get a good deal on it. I can leave one TIG machine in my old shop, and roll my Miller into the new shop. The electrical question is because I'm running another welder outlet into the old shop from the new one, and I can change the wire before I drywall it.

I don't understand the inverters...advantages and disadvantages. If I was to upgrade with a new machine, I would probably go with the Synchrowave 250.

Any ideas about the 110V on the machines themselves? An inspector told me I'd need a neutral wire if I had one, like a range needs 110V and requires 4-wire cable. I don't see how Nick does it with his, unless the ground is treated as a neutral...they are connected together in the breaker box.

[Rick_L]

You need to respect the difference between neutral and ground, especially if you are wiring to code, you'll need both I think. Ground is just what it says. "Neutral" would in some cases seem to be ground but it isn't. If you have GFI outlets in your shop (and you may have to), the GFI will trip if neutral is shorted to ground. And you aren't fully protected if you don't ground your machine.

The only way you could get 120V out of the 6/2 setup (2 hots and a ground) would be to use the ground as neutral.

I just ran into this on a product we're having to build where I work. Discovered that European 240V single phase is like our 120V single phase. One leg is hot, the other neutral in Europe. Here it's two 120V hot wires and a neutral. To have the product work the same US and Europe, I had to have it rewired for 240V only and replace a 120V component with a 240V one.

There are several nice things about an inverter type welding machine. They are quite a bit smaller and lighter for the same power relative to a transformer machine. My inverter machine is in about the same package as my little mig welder and weighs about the same. But it's a 185A machine rather than 125A. On the other hand the 185A output needs 50A/240V input.

The inverter has features like variable frequency (for aluminum), pulse, balance, easy to use pre and post flow, etc. I don't think your 180SD has variable frequency does it? It may have a balance control, not sure. Anyway, these features have really helped my aluminum welding. Remember that my old welder was an Econotig, which doesn't have nearly the features that a 180SD does. So it was a leapfrog deal relative to buying a 180SD, 200SD, or a similar Lincoln welder. Mine is a Thermal Arc 185. The equivalent Miller would be a 200DX. The inverter equivalent to a Synchrowave 250 would be a 300DX. Another thing I like about the inverter is that you can use the same tungsten for both aluminum and steel - no need to keep the pure tungstens on hand and "ball them". You prep them the same for both. (I don't use the very same tungsten for both, just the same type, prepped the same way.)

[chevynut]

You need to respect the difference between neutral and ground, especially if you are wiring to code, you'll need both I think. Ground is just what it says.

I'm pretty good at electronics, and understand what ground is. But this "neutral" BS really has me puzzled.

"Neutral" would in some cases seem to be ground but it isn't. If you have GFI outlets in your shop (and you may have to), the GFI will trip if neutral is shorted to ground. And you aren't fully protected if you don't ground your machine.

I have GFIs in my shop, and it's code here to have them. However, neutral and ground are SHORTED TOGETHER in my breaker panel. So what's the difference?

The only way you could get 120V out of the 6/2 setup (2 hots and a ground) would be to use the ground as neutral.

I agree.

There are several nice things about an inverter type welding machine. They are quite a bit smaller and lighter for the same power relative to a transformer machine. My inverter machine is in about the same package as my little mig welder and weighs about the same. But it's a 185A machine rather than 125A. On the other hand the 185A output needs 50A/240V input.

The inverter has features like variable frequency (for aluminum), pulse, balance, easy to use pre and post flow, etc. I don't think your 180SD has variable frequency does it? It may have a balance control, not sure. Anyway, these features have really helped my aluminum welding. Remember that my old welder was an Econotig, which doesn't have nearly the features that a 180SD does. So it was a leapfrog deal relative to buying a 180SD, 200SD, or a similar Lincoln welder. Mine is a Thermal Arc 185. The equivalent Miller would be a 200DX. The inverter equivalent to a Synchrowave 250 would be a 300DX. Another thing I like about the inverter is that you can use the same tungsten for both aluminum and steel - no need to keep the pure tungstens on hand and "ball them". You prep them the same for both. (I don't use the very same tungsten for both, just the same type, prepped the same way.)

My 180SD doesn't have any settings buy AC/DC and amperage. It does have a high frequency start but not variable frequency. There is no AC balance or pulse. It's pretty basic.

What is the downside to the inverter machines? There must be something you give up....or not? Do they cost more?

The more I think about it the more I'm convinced I'm going to pass on this old HUGE Hobart machine.

[Rick_L]

However, neutral and ground are SHORTED TOGETHER in my breaker panel.

You have already defeated your GFI circuit I think. Maybe a pro electrician could explain it in simple words, I don't think I can.

What is the downside to the inverter machines? There must be something you give up....or not? Do they cost more?

I think the cost is the main thing. Far as I know they are as reliable or more so than a transformer machine. I was able to get my Thermal Arc (obviously not a Miller or Lincoln) for about $2200 about 18 months ago. There was a significant price jump right after I bought mine. They are now about $600 more. I think a 200DX Miller is over $3500. But a 200SD, the closest new one to what you have, is about $2800 also.

The more I think about it the more I'm convinced I'm going to pass on this old HUGE Hobart machine.

Just depends on the deal. You may want to be patient and let a deal on an inverter come to you for your next machine. You may not truly need it but I think you would like it if you had one. For me, my tig welder was a bit deficient IMO, so it was a bigger gain.