220V 4 wire to 3 wire? [Archive] - FSB Forums

: 220V 4 wire to 3 wire?


plug ugly
04-15-2007, 11:17 PM
the new house we are moving into has a 4 wire 220 in the garage, but my welder and plasma is 3 wire, what do I need to do? whats the 4th wire for?

RLKBOB
04-15-2007, 11:27 PM
I think it's using 2 hots, a neutral and a ground. Pretty sure you just need to eliminate the neutral and use the 2 hots and the ground. Check in the breaker panel to verify which color is hooked up to the neutral to make sure you eliminate the correct wire at the plug end.

MikE2
04-15-2007, 11:51 PM
yeah its a ground.
Just get a new cord and put the ground wire on an internal ground screw on the welder case. Or on a welder you can also tie the ground (green) and netural (white) together at the junction screw in the welder.

Or simply change the plugs out in the house. While you're changing plugs get those damn GFI's out of the garage too

78bronco460
04-15-2007, 11:55 PM
the new house we are moving into has a 4 wire 220 in the garage, but my welder and plasma is 3 wire, what do I need to do? whats the 4th wire for?

You could replace the 4 wire receptacle with a 3 wire of the same amp rating. Just leave the neutral (white) wire disconnected in the junction box. Be sure you tape off the end or cap it with a wirenut so it doesn't contact any of the hots by accident.

MikE2
04-16-2007, 12:05 AM
You'd want to leave the ground disconnected, not the netural.

plug ugly
04-16-2007, 12:09 AM
Id rather swap out the house receptacle

LoneGunman
04-16-2007, 12:15 AM
A neutral is not needed on the welder, disconnect it and cap it at both ends. 4 wire 220 volt lines are mostly used for stoves and dryers where there are 120v circuits within the 220 volt unit (clocks, timers ETC) the 4 wire 220 volt circuit are now code required so those 120v circuits are not using the equipment ground as the grounded conductor (neutral).

Remove the GFCI protection? Yeah they can be a PITA if your equipment is faulty to begin with but if they are removed and someone ends up dead as a direct cause of the removal I wouldnt want to be in your shoes.

metal1313
04-16-2007, 12:19 AM
yea i sorta like my gfci's out side and in my house, being electrocuted again is not my idea of fun.

Steve83
04-16-2007, 01:47 AM
Don't leave the ground wire loose - tie it to the neutral.

It's probably cheaper & easier to change the cord on the welder than to change the socket. And just think: once it has the new 4-plug, you'll be able to use the welder in the kitchen! :D

MikE2
04-16-2007, 01:52 AM
A neutral is not needed on the welder, disconnect it and cap it at both ends. 4 wire 220 volt lines are mostly used for stoves and dryers where there are 120v circuits within the 220 volt unit (clocks, timers ETC) the 4 wire 220 volt circuit are now code required so those 120v circuits are not using the equipment ground as the grounded conductor (neutral).

Might work with some welders, but with most of them I doubt it. Especially a wire feed. Even if it does, taking the netural out would be stupid since you wouldn't be able to plug anything in to that plug except for the very very few things that will work without a netural.


If you have a refrigerator or an auto-defrost freezer in the garage take the GFI out and put it on a regular plug.

LoneGunman
04-16-2007, 05:04 PM
Might work with some welders, but with most of them I doubt it. Especially a wire feed. Even if it does, taking the netural out would be stupid since you wouldn't be able to plug anything in to that plug except for the very very few things that will work without a netural.


If you have a refrigerator or an auto-defrost freezer in the garage take the GFI out and put it on a regular plug.

Just about everything youd put on a 220v line will work without a neutral. I've been an electrician for 12 years, obviously in that time Ive ran a good amount of 220v circuits with a good amount of those being for welders in industrial, commercial and residential applications, I have not seen one welder not function without a neutral.

You can use a single receptacle for an appliance like a freezer in a garage without GFCI protection and still be code compliant.

I'm not even really against doing away with garage gfi's, besides being a code violation, but many houses have one GFCI in the garage that also protects the outside receptacles and the bathroom, outside and bathroom you really want GFCI protected.

78bronco460
04-16-2007, 09:00 PM
You'd want to leave the ground disconnected, not the netural.

Wrong

Don't leave the ground wire loose - tie it to the neutral.

It's probably cheaper & easier to change the cord on the welder than to change the socket. And just think: once it has the new 4-plug, you'll be able to use the welder in the kitchen! :D

Wrong also

yeah its a ground.
Just get a new cord and put the ground wire on an internal ground screw on the welder case. Or on a welder you can also tie the ground (green) and netural (white) together at the junction screw in the welder.

Or simply change the plugs out in the house. While you're changing plugs get those damn GFI's out of the garage too

Wrong again, but after you said to leave the ground disconnected this doesn't surprise me. Placing a neutral under a ground screw with a ground wire is dangerous and ignorant. There is only one place in the whole wiring system that bond is done, and it's at the service.
Sorry to be an a-hole but some of the wiring advice on these 4x4 sites is just scary.

MikE2
04-16-2007, 09:59 PM
Just about everything youd put on a 220v line will work without a neutral. I've been an electrician for 12 years, obviously in that time Ive ran a good amount of 220v circuits with a good amount of those being for welders in industrial, commercial and residential applications, I have not seen one welder not function without a neutral.

Well like I said some welders might work, as long as there is no 120 volt circuits in it. And "just about everything"....? No. Maybe 2 or 3% of things made today that require a 240 volt plug will work without the netural.


It would be stupid to wire up a plug with no netural anyways. There is no reason to do it except for saving a little money on copper.

MikE2
04-16-2007, 10:05 PM
Wrong
wrong


Opening the netural line to the recepticle and running its netural to the ground instead is one of the dumbest things I have heard of





Wrong again, but after you said to leave the ground disconnected this doesn't surprise me. Placing a neutral under a ground screw with a ground wire is dangerous and ignorant. There is only one place in the whole wiring system that bond is done, and it's at the service.
I didn't say put the netural under a ground screw. I said if he put a 4 wire cord on the welder to put the ground wire from the new cord on to a ground in the welder. Or put the neutral and ground together right at the netural screw where the cord attaches to the welder. Besides what you think, doing that on a welder its 100% safe. Many things today come with an internal bond connecting the netural to a ground anways. If a grounded plug is used and a 4 wire cord, then that bond is seperated and the ground wire from the cord is put in place of it. While that will seperate the ground and neutral lines, manufacturers still advise using ground wires with 3 prong plugs without seperating the internal ground connection.

InfoFord
04-16-2007, 10:38 PM
hell with just git rid of the welder Problem solved :thumbup :toothless

LoneGunman
04-16-2007, 11:33 PM
Well like I said some welders might work, as long as there is no 120 volt circuits in it. And "just about everything"....? No. Maybe 2 or 3% of things made today that require a 240 volt plug will work without the netural.


It would be stupid to wire up a plug with no netural anyways. There is no reason to do it except for saving a little money on copper.

It would still work even if it had 120 volt circuits in it, how do you think stove clocks and lights worked for years on a 3 wire circuit? The ground acted as the neutral, thats why the code was changed, you don't want the ground to act as the neutral.

78bronco460
04-16-2007, 11:35 PM
I think there's some confusion here, as usual, so let's go over this again...
The problem is there is a 4 wire receptacle that the brother wants to be able to use his 3 wire equipment from. Are we all good with that so far?
The 4 wire receptacle would be fed from a (?)amp 2 pole breaker: 2 hots, a neutral and a ground feeding the 4 wire receptacle. Still good?
The recommendation I and others made is pretty straightforward: remove the 4 wire receptacle, and install the 3 wire receptacle of a similar voltage and current rating. If this part gets confusing let's go into some detail... His equipment is already wired, and for the hell of it let's just assume it's been done correctly. The 3 wire receptacle is the part that is in the wall. It has 3 terminals on it and they are for connecting the two hots and the ground (green or bare) wire. So the use of the existing circuit wires to wire this 3 wire receptacle correctly leaves the white (neutral) wire without a terminal. That's why it would be abandoned and safe-ended for possible future use. Enough detail?
There are instructions in the operators/installation manual of every welding machine I have ever wired...
"Install equipment in accordance with the US National Electrical Code, local electrical codes, and manufacturer's recommendations"
"Ground the equipment in accordance with the US National Electrical Code and manufacturer's recommendations"
The NEC does not permit the use of the groundED (neutral, identified, white or natural gray) conductor as an equipment ground. It also forbids any load side (of the service bond) connection of the groundED (neutral, identified, white or natural gray) conductor to the groundING (green, green/yellow stripe, bare) conductor. That's the reason why I say DON'T DO IT!
Mike2... you've got 18 and a half thousand posts in less than 3 years. When have you had time to learn electrical work?

78Project
04-16-2007, 11:52 PM
hell with just git rid of the welder Problem solved :thumbup :toothless

If you're gettin' rid of the welder, I'll buy it. :thumbup

JimC

Steve83
04-17-2007, 01:24 AM
Don't leave the ground wire loose - tie it to the neutral.Wrong alsoI was talking about the ground on a 4-wire cord being installed on the old 3-wire welding machine. They should be tied together. There's nothing wrong with RE-connecting the ground & neutral circuits. The only time it could ever be a problem is if you were disconnecting the mains with the breakers still installed & the welder switched on. Then you MIGHT end up with the whole house grounding thru the welding machine, but that's a ridiculously slim chance.

78bronco460
04-17-2007, 09:27 AM
I was talking about the ground on a 4-wire cord being installed on the old 3-wire welding machine. They should be tied together. There's nothing wrong with RE-connecting the ground & neutral circuits. The only time it could ever be a problem is if you were disconnecting the mains with the breakers still installed & the welder switched on. Then you MIGHT end up with the whole house grounding thru the welding machine, but that's a ridiculously slim chance.

So you know better and still tell others who don't know better to do it? Great.

plug ugly
04-17-2007, 01:12 PM
also found out its a 30A breaker, can i bump that up to a 50?

doc
04-17-2007, 01:20 PM
also found out its a 30A breaker, can i bump that up to a 50?


No, unless the original installer used larger capacity wiring other than the #10 or #8 (depending on length) required w/ the 30 amp circuit to accomodate the 50 amp circuit breaker.

Steve83
04-17-2007, 01:50 PM
So you know better and still tell others who don't know better to do it? Great.That makes absolutely no sense. :wacko I don't think you're following what I'm trying to say, but I don't know how to say it any clearer than this: tying the neutral to the ground inside the welder when upgrading to a 4-wire cord & plug is safe & correct. It's also the cheapest way to solve the problem, and allows the most flexibility.

78bronco460
04-17-2007, 07:09 PM
That makes absolutely no sense. :wacko I don't think you're following what I'm trying to say, but I don't know how to say it any clearer than this: tying the neutral to the ground inside the welder when upgrading to a 4-wire cord & plug is safe & correct. It's also the cheapest way to solve the problem, and allows the most flexibility.

I understand what you're saying, and I was wrong. You don't know better. Again I'm gonna apologize for being an a-hole. I truly am sorry for that. But let's look at what it is you're suggesting here:
An electrical service is required to have a bond between the neutral and ground at the point of the first disconnecting means, and nowhere else. Agreed?
Now my understanding of what you suggest Steve, is effectively to create a second bonding point within a cord and plug connected equipment. Is that correct or not?
That is the part that is unsafe and forbidden by the NEC. There are many reasons, but I'd rather not give a grounding and bonding class in a 4x4 forum on the internet.
So if there's something I still don't get, sorry for the waste of bandwidth and hope nobody gets shocked or burns down their homes.
Peace.
Jim

MikE2
04-17-2007, 07:13 PM
It would still work even if it had 120 volt circuits in it, how do you think stove clocks and lights worked for years on a 3 wire circuit? The ground acted as the neutral, thats why the code was changed, you don't want the ground to act as the neutral.
Yes there is confusion...

I'm refering to a netural as the center prong on a 3 prong 240 plug. It appears you are calling it a ground.


I think there's some confusion here, as usual, so let's go over this again...
The problem is there is a 4 wire receptacle that the brother wants to be able to use his 3 wire equipment from. Are we all good with that so far?
The 4 wire receptacle would be fed from a (?)amp 2 pole breaker: 2 hots, a neutral and a ground feeding the 4 wire receptacle. Still good?
The recommendation I and others made is pretty straightforward: remove the 4 wire receptacle, and install the 3 wire receptacle of a similar voltage and current rating. If this part gets confusing let's go into some detail... His equipment is already wired, and for the hell of it let's just assume it's been done correctly. The 3 wire receptacle is the part that is in the wall. It has 3 terminals on it and they are for connecting the two hots and the ground (green or bare) wire. So the use of the existing circuit wires to wire this 3 wire receptacle correctly leaves the white (neutral) wire without a terminal. That's why it would be abandoned and safe-ended for possible future use. Enough detail?
Now why would you be using the ground wire instead of the netural?



Mike2... you've got 18 and a half thousand posts in less than 3 years. When have you had time to learn electrical work?
I don't know. I tell ya...I bearly have time to take a shit making 20 posts a day

Steve83
04-17-2007, 08:02 PM
...create a second bonding point within a cord and plug connected equipment. Is that correct or not?Yep - now we're reading each other.
That is the part that is unsafe and forbidden by the NEC. There are many reasons, but I'd rather not give a grounding and bonding class...Now that I'm sure you understood what I was suggesting, I'm perfectly content to agree to disagree. I don't have the NEC memorized, and I don't doubt that you know it better than I, but that's still how I'd convert a 3-prong device to work in a 4-prong socket. And I think we both know it would NEVER set anything on fire or shock anyone, no matter how many rules it breaks.

BTW
How do you think a 220V welder originally built & UL-certified with a 4-prong plug is wired internally? Are the neutral & ground circuits isolated somehow? Or are they tied together? For that matter: how is ANY appliance with a 4-prong plug wired internally? Every one I've ever opened has those 2 wires tied together. And I'm not 100% sure on this, but it seems like the instructions that come with a 4-prong cord (like for a new dryer or stove) say to tie them together.

78bronco460
04-17-2007, 09:00 PM
Yes there is confusion...

I'm refering to a netural as the center prong on a 3 prong 240 plug. It appears you are calling it a ground.



Now why would you be using the ground wire instead of the netural?

That right there is the problem, Mike. The old way of wiring ranges and dryers with SE cable using the neutral for ground is over and done. The code no longer allows it. With plastic water pipes and meter main services feeding subpanels in the homes there are just too many ways for that installation to go wrong.

I don't know. I tell ya...I bearly have time to take a shit making 20 posts a day
LMAO

78bronco460
04-17-2007, 09:27 PM
Yep - now we're reading each other.
Now that I'm sure you understood what I was suggesting, I'm perfectly content to agree to disagree. I don't have the NEC memorized, and I don't doubt that you know it better than I, but that's still how I'd convert a 3-prong device to work in a 4-prong socket. And I think we both know it would NEVER set anything on fire or shock anyone, no matter how many rules it breaks.
If I hadn't seen so many "nevers" happen, I'd see no harm in it either. But consider what the situation would be if the service neutral failed open (it happens), or the water bond was cut by a brush axe (seen that too). These are examples of why the rules are the rules, you see.
The reality is this stuff gets people killed. Really killed really dead. I have often suggested in the past people hire a competent electrician for this reason, but we all know how that goes over. So if I seem too serious then forgive me, but it's serious business.

BTW
How do you think a 220V welder originally built & UL-certified with a 4-prong plug is wired internally? Are the neutral & ground circuits isolated somehow? Or are they tied together?
Yes, they are isolated. The neutral gets used for 110v pilot lights and fan motors, control circuits, that kind of stuff. The ground is just the ground.

MikE2
04-17-2007, 09:36 PM
That right there is the problem, Mike. The old way of wiring ranges and dryers with SE cable using the neutral for ground is over and done. The code no longer allows it. With plastic water pipes and meter main services feeding subpanels in the homes there are just too many ways for that installation to go wrong.


OK then let me ask you this.....Why is the netural any different then the ground?
The ground is grounded at the meter, the netural is grounded at the transformer...?

78bronco460
04-17-2007, 09:41 PM
The neutral is intended to carry circuit load, the ground is intended to keep exposed metal of equipment at zero potential, and to facilitate the operation of the circuit breakers in case of a fault.
My kid's an apprentice... I should have him type all this stuff for extra credit.

MikE2
04-17-2007, 09:44 PM
Ok so then why would you be using a ground as a netural on a 3 prong 240 recepticle? There is going to be 120 volt things putting a load on that ground

78bronco460
04-17-2007, 10:00 PM
Ok so then why would you be using a ground as a netural on a 3 prong 240 recepticle? There is going to be 120 volt things putting a load on that ground
A 3 prong 240 plug/receptacle is for 240 volt loads. It says so right on it. 2 hots and a ground. That's all you get. One prong HAS to be a ground in a cord and plug connection. A 4 wire receptacle says 120/240 on it. That's what you use if there is a neutral required.
When a welder has "120v things" in it they are usually run from an internal transformer that has no need for an external neutral. It is internally derived and part of the equipment. This is a lot more common on 480v welders than on 240v welders, but that's the way they're built.

MikE2
04-17-2007, 10:20 PM
If I remember right, here it was Jan 1st 2000 when the 4 prong 240 plugs were code in non-modular homes. Before that, how many times was there a problem with 3 prong 240 plugs that had 120 volt things running on that plug too? Like how many people got killed or houses burned down that wouldn't have happened if it was a 4 prong plug?


And you didn't answer my other question clearly
Why is the netural any different then the ground?
The ground is grounded at the meter, the netural is grounded at the transformer
I know you said one is for load...Whats the actual difference between them? Why can't one or the other be used for the load? Whats the difference between the ground rod under the box and the ground rod under the transformer or at the bottom of the pole?

InfoFord
04-17-2007, 10:34 PM
see I told ya you should have gotten rid of that welder Plug look at all this frenzy over a outlet LOL

easy fix build a extension cord using 6 or 8 guage 4 wire
put the male four prong plug on one end hooking up the two hots nuetral and ground as they should be in it
put a 3 prong female plug on the other in a metal box
wire the two hots and nuetral to the female plug and wire the ground wire to the metal box

no code violations and no molesting of the welder

78bronco460
04-17-2007, 11:03 PM
If I remember right, here it was Jan 1st 2000 when the 4 prong 240 plugs were code in non-modular homes. Before that, how many times was there a problem with 3 prong 240 plugs that had 120 volt things running on that plug too? Like how many people got killed or houses burned down that wouldn't have happened if it was a 4 prong plug?


And you didn't answer my other question clearly

I know you said one is for load...Whats the actual difference between them? Why can't one or the other be used for the load? Whats the difference between the ground rod under the box and the ground rod under the transformer or at the bottom of the pole?
In my experience, the only reason they change the rules is somebody(s) got killed. I had a service call where a granny had got nailed by turning the stove knob with one hand and reached and grabbed the kitchen faucet handle with the other. Both were metal. KHA. It was a bad service ground that did it. This was not an isolated incident.

see I told ya you should have gotten rid of that welder Plug look at all this frenzy over a outlet LOL

easy fix build a extension cord using 6 or 8 guage 4 wire
put the male four prong plug on one end hooking up the two hots nuetral and ground as they should be in it
put a 3 prong female plug on the other in a metal box
wire the two hots and nuetral to the female plug and wire the ground wire to the metal box

no code violations and no molesting of the welder

You've told him to do exactly what he shouldn't Trent, just extended the bad wiring to the outside of the wall.

Trying to help out here is getting ridiculous, I'll move on.

PM me if you need any help, Mr. Ugly. Best of luck and congrats on the new house.

plug ugly
04-17-2007, 11:32 PM
ok, so as I am thinking more about this, Im not crazy about the location of the 220 plug, and since it needs a bigger amp breaker anyway, maybe I will just pull new line and put a new, correct plug. Is this something a dumbass like myself can do, or should I just spend the money and get an electrician? It will be a short run of maybe 10 feet from the panel to the plug.

plug ugly
04-17-2007, 11:35 PM
PM me if you need any help, Mr. Ugly. Best of luck and congrats on the new house.

thanks, Ill keep you in mind

InfoFord
04-17-2007, 11:51 PM
4 prong plug is not bad wiring

and the nuetral and ground is not tied together the metal box that the welder plug is in would be grounded through the forth wire (the ground) thus effectivly would be the same as having a correctly wired 3 prong outlet that should be in a metal and grounded box in the wall

InfoFord
04-17-2007, 11:56 PM
however if you are not confident in wiring you really should just have a electrician put your new plug in for you

to many things that can and do go wrong
and listening to a bunch of yahoos telling you how to do it on the internet is prolly not the best way to learn electrical 101

jam0o0
04-19-2007, 12:48 AM
for the record i wired my 220 extension like 78bronco460 suggested and it works fine.


w . . o . -------green-------------- . o . . . . w
a . . l . l -------red, black---------- .l . l . . . e
l . . . L . -------white----------x . . . . . . . . l
l . . . . . . . . . . . . . . . . . . . . . . . . ^ . . . . d
. . . ^ . . . . . . . . . . . . . . . . . . . . l . . . . .e
. . . male . . . . . . . . . . . . . . . . .female . . .r

shovelhead
04-20-2007, 01:22 AM
guys just cause something works doen't mean it is done right when it comes to electrical installation.like someone said the onlt place where the grounding conductor is bonded to the grounded conductor is at the service.this is not negotiable its a hard rule the reason is rather involved and doesnt make it more or less so.all flexible cords are required to carry a grounding as in green conductor always.ive never seen a welder that has a use for a neutral conductor unless its a 110 volt machine. regards shovelhead electrician by trade but motorhead at heart

Chuck
04-24-2007, 02:32 PM
Wow, there is a lot of VERY bad and dangerous information in this thread. Don't even consider any information given by anyone other than 78bronco460, LoneGunman, shovelhead, and doc, since they're the only ones in this thread who are providing good, safe info.

I think there's some confusion here, as usual, so let's go over this again...
The problem is there is a 4 wire receptacle that the brother wants to be able to use his 3 wire equipment from. Are we all good with that so far?
The 4 wire receptacle would be fed from a (?)amp 2 pole breaker: 2 hots, a neutral and a ground feeding the 4 wire receptacle. Still good?
The recommendation I and others made is pretty straightforward: remove the 4 wire receptacle, and install the 3 wire receptacle of a similar voltage and current rating. If this part gets confusing let's go into some detail... His equipment is already wired, and for the hell of it let's just assume it's been done correctly. The 3 wire receptacle is the part that is in the wall. It has 3 terminals on it and they are for connecting the two hots and the ground (green or bare) wire. So the use of the existing circuit wires to wire this 3 wire receptacle correctly leaves the white (neutral) wire without a terminal. That's why it would be abandoned and safe-ended for possible future use. Enough detail?
There are instructions in the operators/installation manual of every welding machine I have ever wired...
"Install equipment in accordance with the US National Electrical Code, local electrical codes, and manufacturer's recommendations"
"Ground the equipment in accordance with the US National Electrical Code and manufacturer's recommendations"
The NEC does not permit the use of the groundED (neutral, identified, white or natural gray) conductor as an equipment ground. It also forbids any load side (of the service bond) connection of the groundED (neutral, identified, white or natural gray) conductor to the groundING (green, green/yellow stripe, bare) conductor. That's the reason why I say DON'T DO IT!
Mike2... you've got 18 and a half thousand posts in less than 3 years. When have you had time to learn electrical work?

This is the only safe answer if you're only planning to use this outlet for a welder.

If you want to be able to switch back and forth between your welder and a 4-prong dryer, build an adapter. Get two feet of 10-3 SJOW cable, a male four prong plug, and a female three prong that matches your welder. Wire the female end like you normally would -- hots to hots, ground to ground. Do the same in the male end plug, but do not connect the neutral prong to anything, and certainly do NOT connect it to the ground! Problem solved.

Bonding the neutral to the ground anywhere except the main panel ranges from poor sense to downright dangerous depending on the situation. The case of the equipment should NEVER be bonded to the neutral instead of an equipment ground, because this creates a situation where a loose neutral between the equipment and the panel box will energize the case of the equipment at 120V. Might as well just bond the damn case to a hot and be done with it.

I was talking about the ground on a 4-wire cord being installed on the old 3-wire welding machine. They should be tied together. There's nothing wrong with RE-connecting the ground & neutral circuits. The only time it could ever be a problem is if you were disconnecting the mains with the breakers still installed & the welder switched on. Then you MIGHT end up with the whole house grounding thru the welding machine, but that's a ridiculously slim chance.

Why bond them together when the solution that's acceptable by code works just as well? :scratchhe I swear, the code is pretty damn simple, I've never been able to figure out why people come up with all these weird solutions for problems that don't exist. If you're not using the neutral, don't connect it to anything. Simple.

also found out its a 30A breaker, can i bump that up to a 50?

Only if the circuit was wired with oversize wire. Breaker size is determined by wire size.

Yep - now we're reading each other.
Now that I'm sure you understood what I was suggesting, I'm perfectly content to agree to disagree. I don't have the NEC memorized, and I don't doubt that you know it better than I, but that's still how I'd convert a 3-prong device to work in a 4-prong socket. And I think we both know it would NEVER set anything on fire or shock anyone, no matter how many rules it breaks.

BTW
How do you think a 220V welder originally built & UL-certified with a 4-prong plug is wired internally? Are the neutral & ground circuits isolated somehow? Or are they tied together? For that matter: how is ANY appliance with a 4-prong plug wired internally? Every one I've ever opened has those 2 wires tied together. And I'm not 100% sure on this, but it seems like the instructions that come with a 4-prong cord (like for a new dryer or stove) say to tie them together.

Most 220V welders do not NEED a neutral, they run on straight 220V -- NOT a combination of 220V and 110V like an electric range. My Shopmaster 300 runs on straight 220V, there is no neutral connection. Just an 8AWG equipment ground that connects from my panel ground bar to the case of the welder, and nothing else. You forget welders are nothing but a big transformer. The 110V accessory outlet on the front of my welder is stepped down to 110V from 220V by the welder's transformer, and does not use a supply neutral.

If I remember right, here it was Jan 1st 2000 when the 4 prong 240 plugs were code in non-modular homes. Before that, how many times was there a problem with 3 prong 240 plugs that had 120 volt things running on that plug too? Like how many people got killed or houses burned down that wouldn't have happened if it was a 4 prong plug?


And you didn't answer my other question clearly

I know you said one is for load...Whats the actual difference between them? Why can't one or the other be used for the load? Whats the difference between the ground rod under the box and the ground rod under the transformer or at the bottom of the pole?

For the first, here's the scenario. You have a 220V range with a timer that runs on 110V, using the ground as a neutral for the timer and a case ground, which was the usual scenario. The ground becomes faulty between the range and the panel (not uncommon). Now the range case is electrified at 110V, and if someone happens to hit the light switch or any other grounded object while they're leaning on the range they get the shit zapped out of them.

Now, as for the difference. The two systems (neutral and ground) are tied together in the panel box, and are both grounded there (or at the meter, only one or the other). The ground is designed to never have current on it, because if it's carrying any load and the wire gets cut it will energize the cases of ALL the equipment connected to it.

On top of that, the neutral is only guaranteed to be zero voltage at the panel. Any other part of the house your neutral can show a voltage if the circuit is under load. You remember voltage drop in wires under heavy load, like the headlight circuit? Guess where that voltage goes? If you have an outlet at the far end of your house under heavy enough load that you get two volts of drop on the neutral, that means anything connected to the neutral there will be at +2V compared with ground. If you're out in a detached garage and you touch that piece of equipment while you're on damp concrete, you get zapped. Even though the voltage is low, the circuit can still deliver some current in the wrong circumstances.

see I told ya you should have gotten rid of that welder Plug look at all this frenzy over a outlet LOL

easy fix build a extension cord using 6 or 8 guage 4 wire
put the male four prong plug on one end hooking up the two hots nuetral and ground as they should be in it
put a 3 prong female plug on the other in a metal box
wire the two hots and nuetral to the female plug and wire the ground wire to the metal box

no code violations and no molesting of the welder

Very close. Wire the two hots and GROUND to the female plug and the metal box. Connect the neutral to nothing and cap it with a wire nut. The welder doesn't need a neutral, it needs the safety ground.

Davids78Bronco
05-06-2007, 11:32 PM
well ****, my adapter's been wired wrong for the last three years :doh0715:

http://inlinethumb30.webshots.com/1757/1092234658030334069S200x200Q85.jpg

That's what' I did :brownbag I assume I'm to replace the neutral with the ground, and everything will be OK??

plug ugly
05-07-2007, 03:41 PM
i capped the white, rand black and red to the blade terminals and the green to the round terminal. Working fine now, just not in the location I would like.

topdawg1700
05-10-2007, 10:26 AM
OK, heres one I need a little help on. I had a home built last year and requested a single phase 208 /230 receptacle in the garage for an air compressor. Just now getting around to hooking up the air compressor. The builder installed a 30 amp 125/250 4 wire 3 phase receptacle. I do have a plug to fit the receptacle, but I am not sure how to go about wiring it up.


Thanks

Paul

78bronco460
05-11-2007, 01:15 AM
OK, heres one I need a little help on. I had a home built last year and requested a single phase 208 /230 receptacle in the garage for an air compressor. Just now getting around to hooking up the air compressor. The builder installed a 30 amp 125/250 4 wire 3 phase receptacle. I do have a plug to fit the receptacle, but I am not sure how to go about wiring it up.


Thanks

Paul

If it looks like either of these, it's good:
http://www.hubbellcatalog.com/wiring/images/b30_2710a_diagram.JPG
http://www.hubbellcatalog.com/wiring/images/9430a_diagram.jpg
THese are 3 POLE 4 wire grounding type receptacles, not three PHASE. THere's a big difference.
The correct wiring will depend on the equipment you're connecting. If you aren't sure what to do, I'd recommend calling an electrician (Union of course). It shouldn't be over an hour for the service call, and if your machine smokes or your house burns down it's on him not you. Cheap insurance.

topdawg1700
05-11-2007, 09:13 AM
Yes you are right it is not three phase, the receptacle looks like the bottom picture HBL 9430A. My problem is the air compressor I have has only three terminations I am guessing two hot wires and a ground with no neutral since the compressor only ghas these terminals. Should I disconnect the neutral on the receptacle?

78bronco460
05-11-2007, 10:56 PM
Yes you are right it is not three phase, the receptacle looks like the bottom picture HBL 9430A. My problem is the air compressor I have has only three terminations I am guessing two hot wires and a ground with no neutral since the compressor only ghas these terminals. Should I disconnect the neutral on the receptacle?
Just omit the neutral in the cord and plug. No need to rewire the receptacle.

elmo_4_vt
05-15-2007, 12:49 PM
Just one thing that I didn't see anyone specifically answer...

The reason you only connect the ground and neutral at the service entrance is for isolation. If they connect at an additional location, it can cause circulating currents between the two lines, and in the end, heat or fire can result if there is a large enough difference in potential. between the two points.

Don

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