I just got a millermatic 175 welder. 230v, 19.5 amps. I'm going to make an extension cord for it and was wondering what guage wire I should use. Is 12ga enough? (going about 30 feet, just enough to get all the way around the garage, and into the driveway a bit)


Also, the dryer outlet is neutral grounded. Should I use it as is or add a second outlet with a real ground?

Neutral and ground are exactly the same.

Use 3 conductor 8 ga. stranded wire.

My wife's Dad has a really nice welder, he had a dryer cord on it. Worked fine for him. I had to put a different cord on it for my 220 outlet in my garage. I would say you would be fine. At worst, your welder may not weld well?

I think you want the 8 gauge wire for that, I used 4 cunductor orange sheilded 8 guage from Home depot, it's like 88 cents per foot. I have about a 30 foot extension cord, and my setup is the same as yours. I think for a buck a foot you can move up to the flexible wire - I used leftover from wiring the other garage to make my cord.

As for grounding, the welder is neutral grounded as well, so there's not much to be done unless you yank out the OE plug all together and replace it, or have enough ground wire on a wing nut to the chassis of the welder chassis itself (so it can be removed when you are not using the extension cord)

Note: Ground and Neutral are NOT the same thing.

Yes they both end up in the same place. Yet they can sometimes be exclusive of each other in a circuit. This has to do with impendence mismatch. Too long of a story to get into...

Simply put.
Use a four wire system NOT THREE WIRES...!!!!!!

This is the safest way to wire your welder. Also you will need to use the appropriate sized breakers.

A safe way to choose your breakers is have at least 20% overhead for your breaker. I.E. A 20 amp draw would use a 25 amp breaker. breakers come in increments of 5 amps.

By the way, assuming that you have a total of about 20 amps draw across TWO hot leads.. Then 12 gauge would be ok. The book calls out a maximum of 25 amps on a typical 12 gauge solid core wire under 90 degrees constant if my memory serves me right.
(Your using stranded)

I would use 10 gauge.. This simply puts a little headroom in your construct.

And yes.. Some idiot in Sacremento gave me a Electrical Contractors license. So supposedly I am supposed to know what I am talking about.

Cheers,
Twystd1

So your suggestion of a separate ground, where the welder does not have one? I had the 3 cunductor 12 guage wire, I ran a separate sheilded and stranded 12 guage wire along the extension cord and wrapped it up with 3 rolls of electrical tape.

QUOTE (Twystd1 @ Mar 23 2005, 04:01 PM)

Use a four wire system NOT THREE WIRES...!!!!!!

Respectfully, this welder (a TIG 175) has been wired as I described for two years and has accomplished all the welding on 914RS. The welder has a 3-prong plug and it's on a 100amp breaker.

Hmm, here is my understanding of neutral grounding...

The dryer has 2 circuits.. elements run on 230, timing stuff runs on 115. To get both it needs 2 hots and a neutral. In order to avoid running a 4th wire, they just run the neutral to the case of the dryer and call it a ground. You can't use the ground as a neutral, but I guess you can use the neutral as a ground. (using the ground as a neutral where the ground is connected to plumbing would cause your pipes to rust to pieces)

The welder only has 3 wires on it.. I would think that all of the welder would run on 230v, and the thrid would exclusively be a ground for safety. (unlike the dryer)

So what I'm really asking is: Is the neutral ground close enough to a regular ground, or should I add a second plug by my dryer that uses a regular ground?

(the second plug could cause problems because it would then be possible to run the dryer and the welder at the same time... I might have to add a DPDT switch.. then it starts getting expensive)

QUOTE (bondo @ Mar 23 2005, 04:34 PM)

Hmm, here is my understanding of neutral grounding... The dryer has 2 circuits.. elements run on 230, timing stuff runs on 115. To get both it needs 2 hots and a neutral. In order to avoid running a 4th wire, they just run the neutral to the case of the dryer and call it a ground. You can't use the ground as a neutral, but I guess you can use the neutral as a ground. (using the ground as a neutral where the ground is connected to plumbing would cause your pipes to rust to pieces) The welder only has 3 wires on it.. I would think that all of the welder would run on 230v, and the thrid would exclusively be a ground for safety. (unlike the dryer) So what I'm really asking is: Is the neutral ground close enough to a regular ground, or should I add a second plug by my dryer that uses a regular ground? (the second plug could cause problems because it would then be possible to run the dryer and the welder at the same time... I might have to add a DPDT switch.. then it starts getting expensive)

The three wires are hot 110v, hot 110v and neutral. 220 is the addition of the 2 110s.

If the welder has two hot leads and a neutral with no dedicated ground, what's the point in changing your plug type at the dryer, to supply a ground (and then you need to make sure that your dryer wiring has a ground lead) to a welder that doesn't have a provision in its plug for that ground? Sure it would be safer to make a ground lead for the one that doesn't exist on the welder you are plugging in?

When I did the last garage I used 4 conductor wire, two hots, nuetral and a bare ground wire. First it went into a 220V outlet, then I used one branch of that hot lead to run 1 circuit of 110v, and the other hot lead to 2nd circuit - used brown and grey outlets to tell which circuit is which - on a 30 amp breaker. Saved my bacon on wiring expenses. However the first time through I bought 3 conductor wire and once I ran it and realized my goof, I replaced it with the 4 conductor stuff and the 3 conductor went into a coil in the corner - till I added a separate sheilded wire to it and made a 220v extension cord out of it.

What people are saying is DO not use the bare copper ground wire for your neutral, use a sheilded wire. Which you only get by getting 4 conductor wire, 3 conductor is hot, nuetral and a ground wire - which you need an additional sheilded wire for your 2nd hot to make 220v

QUOTE (914RS @ Mar 23 2005, 04:42 PM)

The three wires are hot 110v, hot 110v and neutral. 220 is the addition of the 2 110s.

I realize that, but I don't think the welder uses the third lead (neutral or ground) for anything but grounding the case, and protecting the user.

I just checked the circuit diagram for the welder. It shows the ground going straight to the case, no 115v circuitry at all. According to the manual it should have 2 hots and a ground, no neutrals.

My dryer has a place to disconnect where the neutral grounds to the case. It has instructions for converting it to "real" ground, using a 4 wire plug (still need the neutral for the 115v timer stuff). Apparently some codes do not allow neutral grounding of dryers (do any allow neutral grounding of welders?)

Perhaps I should just go 4 wire for the dryer, and just not use the neutral for the welder. I need to go shopping and price out various alternatives.

QUOTE (bondo @ Mar 23 2005, 06:00 PM)

Perhaps I should just go 4 wire for the dryer, and just not use the neutral for the welder. I need to go shopping and price out various alternatives.

OK, this is getting a little out of hand. This is a simple wiring project with a simple solution.

Your 3-wire dryer plug will support the welder.

To make your extension cord:

1. buy a plug that fits the dryer outlet.
2. buy a socket that fits the plug on your welder.
3. buy 8 ga. 3 conductor stranded cable (which actually has four wires-the fourth is bare).
4. Wire the 3 prong plugs by using the three shielded cables. The bare fourth will not be used.

Black is hot, Red is hot, White is neutral/ground (It doesn't matter for this set up), Bare is an unused second ground.

Note: if your welder doesn't already have a plug on it, then use the cable you purchased and connect it directly to the welder in the way I described without using the bare fourth wire.

If you have questions, pm me.

It's getting more complicated than what it really is, sorry! Here's a pic

I understand that it will work fine if I just wire it up. Heck, it would work just the same if I only used 2 wires. The issue I am trying to resolve is safety. I'm guessing it is almost as safe as using a real ground. I get isolation through the transformer as well. Probably just as safe as using it to ground a dryer. I HAVE experienced a neutral failure though.. The insulation failed in the line to the pole. The neutral wire was intermittently shorting to one of the hot wires.. which gave half the house 230 instead of 115.. A tv that was off was turning itself on and making strange noises. Several power strips failed open, lights were getting REALLY bright and one power strip melted. If using a neutral ground when that happens, the case of the welder would then be "hot" relative to real ground (that I'm standing on). I guess that's just unlikely enough that I shouldn't worry about it.

QUOTE (Travis Neff @ Mar 23 2005, 07:06 PM)

It's getting more complicated than what it really is, sorry! Here's a pic

Thank you very much, Travis.

I would have taken the same picture if I were home.


Bondo, If your neutral shorts to hot, the breaker will trip.

There is NO (none, nada) safety issue with wiring it as Travis and I have stated.

i hate to step in here, after all of this discussion, yes i am a master electrician.

but your idea for the cord is fine, you only need 10 gauge wire for the welder, its rated to 30 amps. you could use 12 gauge its rated to 20 amp ( clayton is also right 12 is rated to 25 but you have to breaker it at 20 ) but better safe than sorry, the dryer is breakered at 30 so safety says use same wire as breaker dictates. as for using a bare copper or insulated ( sheathed for everyone else ) for the ground is realy not a problem either way as long as it is connected at both ends. i would recommend you use SO or SJO cord in 10-3, what that means is it is a flexible cord with 3 conductors. it is numbered differently than house wire which would be 10-2 with ground

410 534 7319 for any other questions

QUOTE (914RS @ Mar 23 2005, 07:33 PM)

Bondo, If your neutral shorts to hot, the breaker will trip.

Only if it happens after the breaker.. in the situation I mentioned it happened on the main line to the house. I guess eventually the transformer would fail/explode. I slept elsewhere that night (after unplugging everything I could find) and the power company came and replaced the line the next day. The landlord paid for the broken power strips

In reality you're right... no real difference. The chances of that happening are very low. If it does, getting shocked off my welder will be the least of my worries. I'll just make an extension cord that's also an adapter. (like you guys have been telling me from the beginning)

Sorry to be such a thorn in everybody's side, I'll shut up now.

All hail the god of archives
I searched before asking and found some good threads on this subject, including this one. But I still have a few questions.

1. What's the upper limit on how long a 220V extension cord can be before it becomes a problem?


2. If the welder is rated at 20 amps why did they put a 50 amp plug on it? Don't they know that most of their customers are guys trying to repair rusty cars in their garages?

I've got an idea. Why don't you just buy a nice 220V welding extension cord. Or is this a case of 914 owner CSOB syndrome?

Welding Extension Cable

That extension cord would work, but I think the problem is the dryer outlet is a different plug. He'd have to change the plug to a dryer plug to make it work.
A CSOB 914 owner would have to either change out the plug or make a short conversion cord. And that would lead to more spending for a CSOB.

Not that us 914 owners are CSOB's

QUOTE (sj914 @ Jan 16 2006, 06:42 AM)

That extension cord would work, but I think the problem is the dryer outlet is a different plug. He'd have to change the plug to a dryer plug to make it work. A CSOB 914 owner would have to either change out the plug or make a short conversion cord. And that would lead to more spending for a CSOB. Not that us 914 owners are CSOB's

Exactally. It's a combination of CSOB syndrome, needing to adapt the dryer outlet, and that the dryer (and fuse panel) are on the other side of the garage.

But that's a better price on the 25 ft extension than the $90 that I saw.


Jon

QUOTE (jonwatts @ Jan 16 2006, 12:51 AM)

All hail the god of archives I searched before asking and found some good threads on this subject, including this one. But I still have a few questions. 1. What's the upper limit on how long a 220V extension cord can be before it becomes a problem? 2. If the welder is rated at 20 amps why did they put a 50 amp plug on it? Don't they know that most of their customers are guys trying to repair rusty cars in their garages?

1. Depends on the minimum voltage the device with correctly operate under peak and continuous operating current. Generally you want less than a 10% voltage drop, but for a welder I'd keep it under 5% so you don't have problems with the wire feed motor at max. peak amps. Use a wire gauge chart such as this one to size the wire.

2. Possibly because 25-30 amp single-phase receptacles are not as common for household use. More people probably have dryer outlets close to the garage. You could go down to a smaller amp plug rated higher than the max. input amps on the welder, but you'd still have to buy the matching receptacle. And it shouldn't be a standard plug used for 115V equipment even though they exist with 20 amp ratings.

the industry has changed from 3 wire to four wire.

Im MASS, the code now calls for 4 wire.

Get a flexible wire...

I run 100 FT of extension for my 220 machinery.

With the welder, it does draw alot more amps while running than a typical machine due to how it is using the electricity.

I would say that you hard wire it to as close as you can with the stiffer 8 or 10 guage so you experience less voltage drop.

You will feel the voltage drop, and you would notice it more if you were starting a larger motor on a saw/mill.

With this voltage drop your welder will perform less than it should.

The hard wire larger guage will let the voltage to flow easier.

Think of it like water...it flows better through a larger pipe.
With less resistance you will have a better solution.

then you can plug the welder in directly to a plug.
Wire it directly to the circuit box, it will be a better solution.

Rich

QUOTE (r_towle @ Jan 16 2006, 11:58 AM)

the industry has changed from 3 wire to four wire. Im MASS, the code now calls for 4 wire. Get a flexible wire... I run 100 FT of extension for my 220 machinery. With the welder, it does draw alot more amps while running than a typical machine due to how it is using the electricity. I would say that you hard wire it to as close as you can with the stiffer 8 or 10 guage so you experience less voltage drop. You will feel the voltage drop, and you would notice it more if you were starting a larger motor on a saw/mill. With this voltage drop your welder will perform less than it should. The hard wire larger guage will let the voltage to flow easier. Think of it like water...it flows better through a larger pipe. With less resistance you will have a better solution. then you can plug the welder in directly to a plug. Wire it directly to the circuit box, it will be a better solution. Rich

Just hardwire it and be done once and for all. We finished wiring our garage a few weeks ago and just put in special 50A outlet and breaker in the panel for the welder. Much safer than a huge extension cord and less voltage draw. IIRC we used 8ga wire to link the outlet to the panel. Nice and easy and now we can forget about it. No cords to trip over. Its very simple to do and much easier to run than the four strands of #1 wire that were run from the house to the garage. Pulling those things are hard, wiring a simple outlets not bad and it saves lots of trouble in the future. It should be comprable pricewise to and cord you could make because you only need to buy one plug as opposed to 2 for an extension cord, and then you just need a breaker on top of that and the same length of wire.

Also, like Clayton said earlier, ground and neutral are 2 different things, don't run them together. Ground is ground whereas neutral measures current loss for GFI breakers so that they blow when the current loss it too great, like when you are dancing because you are getting electricuted.

In any case, go by building code and be safe, that much voltage can hurt really bad

Nothing electrical here, but for MIG sets, please make sure your gas bottle is secured. In the picture above the bottle appears to be just stood upright on it's own....

Those things have 1000s of PSI in them when they are full.

A friend of mine tells a story about one which got knocked over and smashed the brass valve. After it had flown around the room a few times, it flew through a brick wall, and they found it a quarter of a mile away.

I would get a welding cart and make sure the bottle is secured to the top of the back of the welder.

Just my 2c. Be safe.

QUOTE (jd74914 @ Jan 16 2006, 09:27 AM)

Just hardwire it and be done once and for all. We finished wiring our garage a few weeks ago and just put in special 50A outlet and breaker in the panel for the welder.

That's a great solution but I'm not rewiring my garage.

Thanks for the answers. I'm only looking to make about a 30' extension cord (like bondo was talking about earlier).

I know my local home depot has 4-conductor #6 flexible cord. If they have 3 conductor too then that's all you need since it's just two hots and ground on the welder. Wire one end directly into the welder and the other to a dryer plug and you're done.

QUOTE (fiid @ Jan 16 2006, 09:28 AM)

A friend of mine tells a story about one which got knocked over and smashed the brass valve. After it had flown around the room a few times, it flew through a brick wall, and they found it a quarter of a mile away.

I saw a hole in the wall of a concrete block building from a similar incident. No one got hurt real bad, but one of the guys got some pretty good burns. The guys told me the thing took off like a rocket, literally.


Also turn off your regulator too. It's better for the diaphram in the regulator, and less of a hazard. If you leave the regulator "on" and open the valve the compressed gas cylinder, there's a sudden rush of gas that heats up the valve in the regulator. This is especially critical on oxygen cylinders. If by chance there's ANYTHING combustible inside that valve (like a spider web) it's BOOOM! I've seen pictures of the results.