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chevynut
09-03-2013, 08:43 AM
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
09-03-2013, 10:51 AM
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
09-03-2013, 11:00 AM
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
09-03-2013, 11:06 AM
Yes dryers are on a 30 amp circuit. 50 amp is used for range.

chevynut
09-03-2013, 11:10 AM
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
09-03-2013, 12:36 PM
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
09-03-2013, 01:13 PM
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
09-03-2013, 04:39 PM
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
09-03-2013, 05:44 PM
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
09-03-2013, 06:54 PM
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.

warren57
09-03-2013, 07:46 PM
Check the tag on the Hobart. Keep in mind, it will be rated at 100% output, which you will NEVER reach. Also recommended circuit size (which factors in huge safety) and actual load are two different things.You'll be lucky if you ever reach 50% of the load rating. 50 amp is plenty for the machine you are proposing. As for wire, nope... 220 single phase takes three wires, the fourth is the addition of a ground rod. I did pound in an additional rod at my shop panel, because I tied in at the feed to the meter, not at my house panel. So, from the meter, the house is fed with 3 wires (mine from United Power), the ground rod adds the fourth wire you see in your panel. At my meter, United power has a main breaker in their box and it had room for a couple additional breakers. I added a 50 Amp (called them first and they said their source from the transformer was unlimited, so add any amp load I desired). Ran three wires to my sub panel at the shop, added a ground rod and grounded the panel (and the metal building). My 220 lift, welders, etc are all three wire connections. If you get power from xcel and you add a sub panel fed from your house panel, most inspectors want the 4th wire, connecting both panel grounds together.
The ground terminates at the same buss bar as the neutral. The ground was added to modern electrical as a back up for neutral that might go bad (break), leaving you as the source to ground. (the reason modern receptacles have three prongs, not two, like years ago) Single phase panels have 3 buss bars, the two the breakers are attached to are 110v each (on different transformer phases) therefore one 110v from each buss bar connected to a device will create 220v. The neutral is were any misc. unused power is sent to ground. This keeps the ground from shocking you if you touch it (like touching a metal drill). Now GFI's measure shorts and trip at 1/60,000 of a second (or something like that) so you can't get shocked from a short even if you stand in a bucket of water and touch the wires! and arc fault breakers detect an arc, in a switch, light bulb, motor, wire anything that arcs, but not necessarily a short. New in 2009 NEC and a pain in the but in the shop or anywhere a brush type motor operates (a vacuum cleaner), but again they trip upon detection of an arc of any type.
This is a very brief description of electrical. Call me if you want to talk in detail. Have several friends that are electrical engineers and a couple master electricians that taught me the ropes many years ago. Since, I've wired all the homes I've built though the years and helped many of my friends with theirs.

chevynut
09-03-2013, 09:14 PM
Rick and Warren, thanks for the attempt at explaining this stuff. I don't really understand how GFIs work in detail, since I've never studied them. However, I know that they somehow measure the current to ground and trip if they detect any. What I don't understand is how they still can work when ground and neutral are bonded together at the breaker panel. The ground wire goes AROUND the GFI, not through it. So if neutral and ground are essentially the same thing at the panel, how can it measure current to ground? Maybe it detects the current LOSS that should be going back through the neutral wire but isn't? We have to use GFI in any garage or shop, bathroom, kitchen, or any possible wet location. And I am pretty sure we also have to bond the ground and neutral together in the panel by code. That's the way it is in my old shop, I think. Then the ground buss is connected to a ground rod outside the old shop. The new shop panel is grounded to the foundation with rebar embedded into the footings...that's the new code.

Now, getting back to making a 110V outlet on a 220V machine. Is it okay to use ground as neutral in that application, since there's no GFI involved? Seems like it would work, but the ground wire would be bare. Maybe no issue there, but don't know if it's legal. If I need 6/3 with ground, I need to change it now. Rick, does your inverter machine have torch cooling? If so, where does it get power? The cooling unit I can get for my 180SD is 110V and I'd rather not plug it into the wall separately if I get one. The cord going into the welder is 8/3...don't know if that includes ground, but I think it does.

BTW, sometimes my TIG welder, which is on 220V, trips one of my 110V GFIs. It seems to happen when we forget to connect the ground clamp from the welder to the thing we're welding, and try to weld.

Rick_L
09-04-2013, 09:43 AM
As you can probably tell, I'm having the same thoughts about ground vs. neutral as you are. I don't see any way you can connect them together at the panel.

My welder doesn't have a water cooled torch. I connected it to the same receptacle as my Econotig. I have a 4 wire plug and receptacle, but there's no 120V receptacle on the welder. I don't think the neutral wire is connected to anything, unless some of the internal controls or the display runs on 120V. So if I had a cooler, I'd have to run a separate power cord to a 120V receptacle.

chevynut
09-04-2013, 10:15 AM
There is a "bonding screw" in the panel that you use to connect neutral to ground. Warren said "The ground terminates at the same buss bar as the neutral." but mine has two separate bus bars. It's the "bonding screw" that connects them together. I guess some places on earth don't need it and some do, for some strange reason. :)

Rick_L
09-04-2013, 02:01 PM
If you would care to read the wikipedia article that comes up when you googe "ac circuit neutral and ground", most of the questions discussed here are answered fairly well. Nobody was dead wrong in their statements, just more compete answers for the most part.

warren57
09-04-2013, 02:24 PM
There is a "bonding screw" in the panel that you use to connect neutral to ground. Warren said "The ground terminates at the same buss bar as the neutral." but mine has two separate bus bars. It's the "bonding screw" that connects them together. I guess some places on earth don't need it and some do, for some strange reason. :)


Well the reason you see two terminal strips for ground and neutral is to accommodate the number of terminations. The bonding screw in essence makes them a single bar. If you trace the 3 wires back to the transformer or to the pole (if you have a pole) you will see two insulated wires, these are the two 110v feeds, looking at a pole, you will see a bare stranded wire that is connected to the mast at the house, this goes to ground at the pole,through the metal panel case. through the ground and neutral terminal strips and to the ground rod and water pipe ground at the house. The stranded bare wire from the pole serves a dual purpose, a "support" wire to hang the two line voltage wires and as the neutral/ground line.

As for the ground fault breaker, it detects an unbalanced condition between the line side and neutral. In other words (as I understand) the breaker is sensing current (amps) passing through the breaker and trips if you over amp the circuit, the same as a standard breaker, then in addition, it is sensing voltage in the neutral (current coming through the neutral side of the same circuit. If to much voltage is sensed due to a short ( the line side connected to the neutral through a short condition), the breaker will also trip. So, it is a dual purpose breaker, trip on over amperage and trip on short. When you push the test button on the breaker, you are shorting out the line voltage side of the breaker to the neutral side, that imbalance is sensed and the breaker trips.
No sure if that helps or not?




http://0.tqn.com/d/electrical/1/G/S/2/-/-/GFCI-Breaker-Wiring-Diagram-200.jpg http://0.tqn.com/d/electrical/1/G/R/2/-/-/GFCI-Breaker-Sketch-200.jpg




Try reading this, it may make more sense....http://www.homeinspector.org/resources/journals/GFCIs.pdf

Rick_L
09-04-2013, 05:09 PM
Good explanation Warren except that not all GFI breakers are also able to detect an overload.

As you said, what the GFI is detecting is a difference in current between the "hot" wire and the "neutral" wire. In other words if the neutral/ground is shorted or partially shorted to ground at the machine or receptacle, rather than completing the circuit back to the breaker box.

One place where I missed it is that the neutral and ground ARE connected together at the breaker box (I thought they weren't). Except in some instances, which are explained in the article I referenced.

Olderthandirt
09-04-2013, 06:20 PM
The poles in the street do not feed grounds to houses. That bar wire is just to suspend the wires. Ground rods, supply the ground for each meter fit. there is usually one at the meter & one or two at the panel.
Ranges, driers any other similar devises require a neutral & separate ground In the cast that one fails the devise still has a ground. That's why a panel has a ground and a neutral. Electricity wants to seek a ground If the neutral should break with out a ground, it will find another way ground "YOU"
Sub panels the ground & the neutral are separated & run back to the main panel. Long runs from the main panel a additional ground rod is added.
On GFI's it measures the flow between hot & neutral. to test a GIF, place a circuit tester between hot & ground if the GIF is good, it will trip.
I have no electrical training but working in construction for 30 years you pick up information.

chevynut
09-04-2013, 07:38 PM
Ranges, driers any other similar devises require a neutral & separate ground In the cast that one fails the devise still has a ground. That's why a panel has a ground and a neutral.

It's my understanding that since a range requires 110V as well as 220V, that's why the neutral is required. I was told by the inspector that dryers don't require the neutral wire, only the two 110V leads and ground. That may not be the case with the newer dryers and their electronics.


Sub panels the ground & the neutral are separated & run back to the main panel. Long runs from the main panel a additional ground rod is added.

Not sure about that. My entire shop on a subpanel...two actually. The old shop has a ground rod and ground and neutral are bonded in it. I ran another subpanel in my new shop off of the subpanel in the old shop, and it has a ground rod too. I'm betting the inspector tells me to bond neutral to ground. The old shop's subpanel is about 90-100 feet from the house panel, and the new shop subpanel is about 70 feet of wire from the old shop panel.

So basically neutral and ground are the same thing in my shop.

Nobody's really answered my question about getting the 110V at the welder. Will I need a neutral on the welder or not? I believe the cable connected to the welder is hot, hot, and ground. The Hobart welder has the same exact 8/3 cable, and it has 110V outlets on it. I'm betting they're using one power leg and ground.....no neutral. But I'm not sure.

warren57
09-04-2013, 09:25 PM
[QUOTE=Olderthandirt;13376]The poles in the street do not feed grounds to houses. That bar wire is just to suspend the wires. Ground rods, supply the ground for each meter fit. there is usually one at the meter & one or two at the panel.



Kind of... the pole is grounded, the stranded bare wire is grounded at the pole (in Colorado anyway), as it attaches to the mast at the house, the mast is connected to the meter housing and breaker box and the breaker box is grounded to the water pipe and ground rod at that point. Therefore the all metallic components attached to each other are grounded at the house and again at the pole. The 2 insulated wires coming in from the pole attach to each power buss bar. The 3rd (bare wire) coming in from the pole suspends the insulated wires and is attached to the panel neutral buss and becomes the grounded neutral.
Here's a couple of pictures...

warren57
09-04-2013, 09:34 PM
It's my understanding that since a range requires 110V as well as 220V, that's why the neutral is required. I was told by the inspector that dryers don't require the neutral wire, only the two 110V leads and ground. That may not be the case with the newer dryers and their electronics.



Not sure about that. My entire shop on a subpanel...two actually. The old shop has a ground rod and ground and neutral are bonded in it. I ran another subpanel in my new shop off of the subpanel in the old shop, and it has a ground rod too. I'm betting the inspector tells me to bond neutral to ground. The old shop's subpanel is about 90-100 feet from the house panel, and the new shop subpanel is about 70 feet of wire from the old shop panel.

So basically neutral and ground are the same thing in my shop.

Nobody's really answered my question about getting the 110V at the welder. Will I need a neutral on the welder or not? I believe the cable connected to the welder is hot, hot, and ground. The Hobart welder has the same exact 8/3 cable, and it has 110V outlets on it. I'm betting they're using one power leg and ground.....no neutral. But I'm not sure.

OK 110 to the welder, pull a hot of one leg of the 220, it's 110. Use it on line side of device. Use the common neutral on the other side of the device. Now you have a 110v outlet. The third ground wire from the outlet parallels the (white) neutral and either runs back to the panel with the neutral or attaches to the ground screw on the welder frame, which if wired correctly also has a (bare) wire from the metal shell or frame back to the panel.
Now the problem.... you are feeding the welder with a double pole breaker. You want to keep both legs of power fairly equal in load so one side of the breaker doesn't want to trip before the other side.
Correct and best solution, run a dedicated 110 source separate from the 220 to your welder. Pull it off a 110 wall receptacle. Heck, put a cord cap on it and plug it in at the wall when you want it.... many options.

warren57
09-04-2013, 09:48 PM
One place where I missed it is that the neutral and ground ARE connected together at the breaker box (I thought they weren't). Except in some instances, which are explained in the article I referenced.[/QUOTE]


Well, yes they are all connected together at the panel. Look at the neutral buss bar lugs and the bond wire that connects to the additional terminal strips, making them all common to each other (where all the whites and bare wires terminate). They are all connected at random and all are attached to the lugs, Whites (neutrals) and bare (grounds) are intermixed. The terminal strips are screwed to the metal box with screws and therefore are part of the grounding system. The bond wire interconnects all of the neutrals and grounds to the grounding system (rod/water pipe) and the neutral buss bar.
The only buss bars and wires that are insulated from the panel shell (grounding system) are the two line voltage wires and in turn the breakers that connect to those two buss bars. Everything else is attached mechanically to the grounding system.

chevynut
09-04-2013, 11:11 PM
OK 110 to the welder, pull a hot of one leg of the 220, it's 110. Use it on line side of device. Use the common neutral on the other side of the device. Now you have a 110v outlet. The third ground wire from the outlet parallels the (white) neutral and either runs back to the panel with the neutral or attaches to the ground screw on the welder frame, which if wired correctly also has a (bare) wire from the metal shell or frame back to the panel.
Now the problem.... you are feeding the welder with a double pole breaker. You want to keep both legs of power fairly equal in load so one side of the breaker doesn't want to trip before the other side.
Correct and best solution, run a dedicated 110 source separate from the 220 to your welder. Pull it off a 110 wall receptacle. Heck, put a cord cap on it and plug it in at the wall when you want it.... many options.

There is no neutral wire, that's my point. The welder only has an 8/3 cable on it, but it has a 110V receptacle. It has two 110V leads and a ground. My 180SD welder has the same cord. Why would they put a receptacle on the welder if it wasn't correct?

warren57
09-05-2013, 06:40 AM
There is no neutral wire, that's my point. The welder only has an 8/3 cable on it, but it has a 110V receptacle. It has two 110V leads and a ground. My 180SD welder has the same cord. Why would they put a receptacle on the welder if it wasn't correct?


Your welder circuit should have either 3 or 4 wires. Sounds like you have 3. So, 2 are power one is ground (/neutral). The ground wire attaches to the frame/case of the welder. They are using the ground as a neutral for the 110v outlet..

warren57
09-05-2013, 06:45 AM
Good explanation Warren except that not all GFI breakers are also able to detect an overload.

As you said, what the GFI is detecting is a difference in current between the "hot" wire and the "neutral" wire. In other words if the neutral/ground is shorted or partially shorted to ground at the machine or receptacle, rather than completing the circuit back to the breaker box.

One place where I missed it is that the neutral and ground ARE connected together at the breaker box (I thought they weren't). Except in some instances, which are explained in the article I referenced.

Yes, my GFI's do trip on either over amp or short. You buy them in amp rating to protect the circuit from to high amperage. I trip my kitchen GFI on over amp whenever I have the microwave and to many appliances all running at the same time and my garage gfi whenever I have to many things running at one time. Try plugging in a few electric heaters and run your amps over the rating on the breaker and I'll bet it will trip. Unplug stuff and get the load below max amps and I'll bet it doesn't trip.
See attached flowchart/ picture.
Also, here is is a piece of manufacturers literature:
"...GFCI circuit breakers perform two functions. If it is a true circuit breaker it will prevent "over-current" conditions from overheating the wiring of your home and hopefully minimize the potential for fire. All circuit breakers and fuses are designed to 'trip' or 'blow' when an over-current condition exists. GFCI circuits have an additional function. To prevent or minimize the potential for hazardous shocks, GFCI circuits compare the current that goes across the two wires that make up the hot and common voltage lines of an outlet. If the current on the two wires does not match precisely, the assumption is that current is being lost to something outside of the circuit. This condition is called a "ground fault". In simple terms, it means that there is high potential that YOU are grounded, as in standing in a puddle of water, and YOU have touched the "hot" side of the circuit or the device somehow allows current to go outside of the normal voltage path. A ground fault can exist if an outside outlet has become wet with rainwater, or an outside extension cord is laying in water or an appliance is in the process of failing and voltage leaks to the ground wire. But as already mentioned, it can also indicate that the GFCI has failed, although that doesn't often happen.

G.F.C.I. [Ground Fault Circuit Interrupter] trips when it senses a ground fault. In a correctly wired circuit the return path should be on the neutral wire. The circuit will trip if the GFCI senses a difference in the current (Amps) in the Black "hot wire" from what is returning in the White "neutral wire". These two values should be the same unless you are leaking electricity which is called a ground fault. This can happen in a wet location when electricity is using the water as it's ground and not returning back through the neutral wire. Older motors can also leak electricity in to their motor housings. If the electricity is not returning through it's designed path then you may have a safety hazard and your GFCI is protecting you."

I've never seen a gfi breaker that doesn't protect on over amp, but they may very well be out there???

NickP
09-05-2013, 06:48 AM
http://www.nojolt.com/Understanding_240_volt_circuits.shtml




To understand how a 240 volt (also known as 220 volt) household circuit works you should first know a little bit about how a regular 120 / 110 volt circuit works. If you are at all familiar with residential electrical wiring then you probably already know that in most cases appliances, and fixtures connect to three wires:


1) A black wire which is often known as the "hot" wire, which carries the current in to the fixture.
2) A white wire called the neutral which completes the electrical circuit.
3) A bare copper wire called the ground, the sole function of which is to enhance user safety.


When the circuit is in use current is "pushed" through the fixture by way of the "hot" wire and then to ground by way of the neutral, and unless something goes wrong the bare ground wire doesn't do anything except to remain ever vigilant in case of a problem.

Since house current is alternating current the actual direction that the electrons flow reverses direction 60 times per second (60 cycles). Put another way, the hot wire has a negative charge alternating with an equal positive charge, and the polarity of the hot wire reverses 60 times per second.

Now for the quick explanation of 240 / 220 volt house current; Appliances which use straight 240 current (such as electric water heaters, or rotary phase converters) also have three wires:


1) A black wire which is often known as the "hot" wire, which carries the current in to the fixture.
2) Another "hot" wire which may be blue, red or white (if it is white the code actually requires it to painted or otherwise marked one of the other colors, but often it is not) which also carries current in to the fixture.
3) A bare copper wire called the ground, the sole function of which is to enhance user safety.


That's it, no neutral. Now, if you are paying attention, then you are probably wondering "If there isn't a neutral wire then how is the circuit completed?" The answer is that when one hot wire is negative, then the other is positive, so the two hot wires complete the circuit together because they are "out of phase". This is why 240 volt circuits connect to double pole breakers that are essentially two single pole breakers tied together. In the main panel, every other breaker is out of phase with the adjoining breakers. So, in essence 240 volt wiring is powered by 2 - 120 volt hot wires that are 180 degrees out of phase.

I previously mentioned "straight" 240 volt appliances, but there is another class of 240 volt equipment; some appliances (such as clothes dryers and ranges) use 240 volt current to power their main function (drying clothes or cooking food) but use 120 volt current to power accessories such as the clock on your stove or the light inside the oven, or the digital readout on your dryer controls. That is why some 240 volt circuits have four wires:


1) A black wire which is often known as the "hot" wire, which carries the current in to the fixture.
2) Another "hot" wire which is red, which also carries current in to the fixture.
3) A white wire called the neutral which completes the electrical circuit for the 120 volt accessories only.
4) A bare copper wire called the ground, the sole function of which is to enhance user safety.


At one time, the code allowed for one insulated wire to function as both ground and neutral in 120 / 240 volt combo circuits, but now all such circuits must use the 4 wire scheme. This is why your new dryer (or electric range) might have 4 prongs on its plug and your old dryer receptacle only has 3 holes. In which case article 250.140 of the 2005 N.E.C. (National Electric Code) allows for the "pigtail" (the cord and plug assembly) to be changed to match the old 3 wire receptacle as long as certain conditions are met. The National Electric Code allows that, but your local code might not, so check first, or even better yet make a deal with the appliance dealer to do it for you.

Related Articles:
•The basics of installing 220 circuits

Rick_L
09-05-2013, 07:59 AM
Warren, just to clarify, I didn't say your GFIs didn't have overload protection. Just that not all of them do.

warren57
09-05-2013, 03:52 PM
Warren, just to clarify, I didn't say your GFIs didn't have overload protection. Just that not all of them do.

Oh no, I understand. I've never seen one that didn't, but there's a lot of thing I've never seen!!!! And, unfortunately a lot more things I wish I had seen but will likely not. It's amazing what there is in this country that we are to busy to see when we are young and don't have the energy to see when we get old!

warren57
09-05-2013, 03:54 PM
http://www.nojolt.com/Understanding_240_volt_circuits.shtml

RIGHT ON, that's what we have all been trying to say (in our own words)!!!!

chevynut
09-05-2013, 04:44 PM
Thank you guys for all your input on this issue. It really helped. I left the 6/2 wire in place, and we drywalled over it. So it's a done deal. I will probably pass on the welder, and look at getting an inverter model if I upgrade. I may get the cooling setup for my current welder though.

Rick_L
09-05-2013, 07:15 PM
Your welder, or mine, is probably at the amperage limit where you could get away without one. If you're welding thick stuff very often, you probably want one. I don't, but never say never. The biggest downside is that it's just more hoses that are attached to the torch lead (weight and awkwardness), plus it's just another thing to maintain and keep working correctly.

chevynut
09-05-2013, 07:22 PM
Rick, my son welds on the frames we build for sometimes hours at a time. The torch gets very hot. I didn't think it was a big deal until I welded up some of my seat mounts and found out what he was saying. It's not so much the thickness of the metal, it's how long you're welding. It gets hot even on relatively low current....not at the max output anyhow.

NickP
09-05-2013, 07:32 PM
http://welding-tv.com/wp-content/uploads/2011/07/TF-Made-in-USA.png

http://welding-tv.com/the-tig-finger-heat-shield/

Get him one of these - solves the issue and a lot less expensive than a new rig.

chevynut
09-05-2013, 09:07 PM
Nick, it looks like that's to keep from burning yourself on the hot workpiece. The torch itself is getting hot. It burns the index finger, even with gloves on. Plus, doesn't the tungsten burn away easier if it gets too hot? I thought that was part of the reason to get a cooled torch.

I wouldn't get a whole new rig unless I wanted to upgrade. The cooling unit and torch are about $800 for my 180SD. Do you have cooling on your TIG?

Rick_L
09-06-2013, 08:29 AM
Cnut, I think your comments on the torch are correct. Temperature on the outside of the torch is a time and temperature thing. And you're right about the effect on the tungsten too.