OT: 230v welder wiring, using a dryer circuit Options

[bondo]

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?

[Series9]

Neutral and ground are exactly the same.

Use 3 conductor 8 ga. stranded wire.

[Root_Werks]

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? (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

[TravisNeff]

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)

[Twystd1]

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. (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)

Cheers,
Twystd1

[TravisNeff]

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.

[Series9]

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.

[bondo]

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)

[Series9]

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.

[TravisNeff]

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

[bondo]

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.

[bondo]

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.

[Series9]

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.

[TravisNeff]

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) It's getting more complicated than what it really is, sorry! Here's a pic

[bondo]

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.

[Series9]

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

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) 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.

[scotty914]

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

[bondo]

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 (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

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. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) 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. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

[jonwatts]

(IMG:http://www.914world.com/bbs2/html/emoticons/icon_bump.gif)

All hail the god of archives (IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif)
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?

[sgomes]

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? (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

Welding Extension Cable

(IMG:http://store.weldingdepot.com/html/images/items/pxcable.jpg)