Need 220vAC electrical help - change 4 prong outlet to 3-prong

[Arc weld]

http://www.amazon.com/gp/aw/d/B003G...pi=AC_SX110_SY165_QL70&keywords=miller+300517

That would do it ($80) Thx!
But I already have the parts, will probably just build it.

Too funny, that's not even the right picture for the Miller cord. It's more like the cord below it with molded on plugs but shorter.

 

[Sodo]

OK had some time today to work on this. Awhile back I exchanged the 4-hol outle for a 3-holer. I used the ground, but isolated the neutral. This was not right. So today I put back the 4-holer. Nothing special about this pic, it's just the generator restored to OEM. My welder still has a 3-prong plug (50R style). I added a 3-holer, dongle style.

I used 3-wire #8 cord but attached to the 4-wire by "bonding the neutral" inside the dongle male plug. So when it's UN-plugged, the generator is totally original. With the 4-prong plugged in, the neutral gets bonded to ground.

I cut a hole & mounted the 3-holer outlet (NEMA 50R) behind the panel. This is like a Dongle, but permanently mounted to the generator.

TESTED IT and Yes it now runs 120v tools off (one leg of) that 3-holer 240v outlet. If I could do it again I'd move it over so it doesn't impede access to the oil filler.

 

[LDCravey]

The neutral and (safety) ground should never be tied together at the plug or socket. Agreed, ... they are tied together at the main electrical panel, but should not be tied together at the plug. The neutral serves no real purpose when using strictly 220/240 volts from a single appliance since the current enters one hot conductor and returns to the power company via the other hot conductor. However if that appliance has any part inside that runs on 120VAC, then the neutral carries the return current from one leg of the 240 volt lines back to the electrical panel. The (safety) ground should never have current on it except in a fault condition, which should then pass the fault current back to the electrical panel and trip the breaker. When you tie the neutral and the (safety) ground together at the plug, then there could be current flowing on the neutral/(safety) ground as a normal condition. In this case, this neutral/(safety) ground wire could come in contact with your body. Remember the ground wire is usually tied to the metal case of the appliance. If you are earth grounded and you touch the metal case of the appliance. You are now dead. End of story. You have suddenly stopped reading this post.

The NEC (National Electric Code) was changed years ago from requiring a 3 prong plug (hot, hot, (safety) ground) to now require a 4 prong (hot, hot, neutral, (safety) ground). The neutral and (safety) ground has to now be 2 separate conductors, not tied together. To my understanding this was done because certain appliances (like an electric stove or a clothes dryer) sometimes contained small clock motors that ran on 120 volts but the main appliance ran on 240 volts. Because the 120 volt clock motor passed current on the ground conductor on a continuous basis, this was considered a safety hazard that could kill you. The (safety) ground should never normally carry current on this wire except in a fault condition (to save your life). Now that these are tied together in you application, the case of your appliance could be energized with enough current that could kill you. It is strongly suggested that you do not tie these together, if you value your life or other lives that might use your appliance. Consult an electrician that truly understands the difference between neutral and ground. They are not the same even though they are tied to the same point in an electrical panel. They should never be tied to the same point on a plug or socket.

The above can be quickly and easily demonstrated if you want to be the (dead) guinea pig, otherwise, a simple volt meter can tell you that it could kill you. I hate to be a downer, but your wiring methods and NEC violations are serious enough that others should understand why this should never be done.

No, I am not a licensed electrician. I am an engineer.

 

[stuckmotor]

Sodo,
What brand and model welder are you running with the generator? I'm in the thinking stage off buying an outfit.

 

[CNC Dan]

The neutral and (safety) ground should never be tied together at the plug or socket. Agreed, ... they are tied together at the main electrical panel, but should not be tied together at the plug. The neutral serves no real purpose when using strictly 220/240 volts from a single appliance since the current enters one hot conductor and returns to the power company via the other hot conductor. However if that appliance has any part inside that runs on 120VAC, then the neutral carries the return current from one leg of the 240 volt lines back to the electrical panel. The (safety) ground should never have current on it except in a fault condition, which should then pass the fault current back to the electrical panel and trip the breaker. When you tie the neutral and the (safety) ground together at the plug, then there could be current flowing on the neutral/(safety) ground as a normal condition. In this case, this neutral/(safety) ground wire could come in contact with your body. Remember the ground wire is usually tied to the metal case of the appliance. If you are earth grounded and you touch the metal case of the appliance. You are now dead. End of story. You have suddenly stopped reading this post.

The NEC (National Electric Code) was changed years ago from requiring a 3 prong plug (hot, hot, (safety) ground) to now require a 4 prong (hot, hot, neutral, (safety) ground). The neutral and (safety) ground has to now be 2 separate conductors, not tied together. To my understanding this was done because certain appliances (like an electric stove or a clothes dryer) sometimes contained small clock motors that ran on 120 volts but the main appliance ran on 240 volts. Because the 120 volt clock motor passed current on the ground conductor on a continuous basis, this was considered a safety hazard that could kill you. The (safety) ground should never normally carry current on this wire except in a fault condition (to save your life). Now that these are tied together in you application, the case of your appliance could be energized with enough current that could kill you. It is strongly suggested that you do not tie these together, if you value your life or other lives that might use your appliance. Consult an electrician that truly understands the difference between neutral and ground. They are not the same even though they are tied to the same point in an electrical panel. They should never be tied to the same point on a plug or socket.

The above can be quickly and easily demonstrated if you want to be the (dead) guinea pig, otherwise, a simple volt meter can tell you that it could kill you. I hate to be a downer, but your wiring methods and NEC violations are serious enough that others should understand why this should never be done.

No, I am not a licensed electrician. I am an engineer.

All true. but he is talking about a stand alone generator, not house wireing. Some generators come with bonded ground/neutral, some have them seprate. His plug converts his generator from one type, to the other. Not something you would want to hook up to your transfer swich.

Here is a video that shows why you should never use the ground as a neutral.

https://www.youtube.com/watch?v=deArcJtDvhs&feature=youtube_gdata_player

 

[LDCravey]

All true. but he is talking about a stand alone generator, not house wireing. Some generators come with bonded ground/neutral, some have them seprate. His plug converts his generator from one type, to the other. Not something you would want to hook up to your transfer swich.

Here is a video that shows why you should never use the ground as a neutral.

https://www.youtube.com/watch?v=deArcJtDvhs&feature=youtube_gdata_player

The main point I was trying to make was that many people associate neutral and ground as the same since they are tied to the same point in an electrical panel. They believe that if it is tied together at the panel, then it is also acceptable to tie neutral and (safety) ground together at the far end (or at a plug or jack). This is when they create the shock hazard that could potentially kill them or others. Yes, generators may have these bonded together or separate depending on the AHJ (Authority Having Jurisdiction)), but essentially, it is still a power plant that may or may not reference (earth) ground. A power station references earth ground, therefore there are grounding rod on many power poles and the grounding rod at all electrical panels. I am fairly certain that most permanently installed (larger) generators are grounded using a ground rod, therefore they reference earth ground, therefore they would use the (safety) ground wire which is not the neutral wire. If the generator was portable, then earth ground is normally not referenced. Agreed, most portable generators are never inspected by the AHJ, therefore the homeowner's wiring practices are never inspected for safety. Either way, the main point is that the neutral and ground should never be tied together except at the electrical panel (or at the generator), otherwise a safety hazard could be created.

As an FYI to others reading this post, the electrical potential of neutral and (safety) ground at the electrical panel is 0 volts @ 0 amps, (or very very close to this value) however the electrical potential of the neutral and (safety) ground at the far end of a long wire could be an unknown voltage @ an unknown value of amps. It is this "unknown" value that could potentially mess up the day of Mr. Homeowner (or others who use Mr. Homeowner's incorrect wiring methods). It only requires approximately 10ma (.010 Amp) to kill you.

 

[buickanddeere]

OK had some time today to work on this. Awhile back I exchanged the 4-hol outle for a 3-holer. I used the ground, but isolated the neutral. This was not right. So today I put back the 4-holer. Nothing special about this pic, it's just the generator restored to OEM. My welder still has a 3-prong plug (50R style). I added a 3-holer, dongle style.

I used 3-wire #8 cord but attached to the 4-wire by "bonding the neutral" inside the dongle male plug. So when it's UN-plugged, the generator is totally original. With the 4-prong plugged in, the neutral gets bonded to ground.

I cut a hole & mounted the 3-holer outlet (NEMA 50R) behind the panel. This is like a Dongle, but permanently mounted to the generator.

TESTED IT and Yes it now runs 120v tools off (one leg of) that 3-holer 240v outlet. If I could do it again I'd move it over so it doesn't impede access to the oil filler.

Wrong

 

[buickanddeere]

OK had some time today to work on this. Awhile back I exchanged the 4-hol outle for a 3-holer. I used the ground, but isolated the neutral. This was not right. So today I put back the 4-holer. Nothing special about this pic, it's just the generator restored to OEM. My welder still has a 3-prong plug (50R style). I added a 3-holer, dongle style.

I used 3-wire #8 cord but attached to the 4-wire by "bonding the neutral" inside the dongle male plug. So when it's UN-plugged, the generator is totally original. With the 4-prong plugged in, the neutral gets bonded to ground.

I cut a hole & mounted the 3-holer outlet (NEMA 50R) behind the panel. This is like a Dongle, but permanently mounted to the generator.

TESTED IT and Yes it now runs 120v tools off (one leg of) that 3-holer 240v outlet. If I could do it again I'd move it over so it doesn't impede access to the oil filler.

Wrong

 

[aczlan]

Wrong

How about expounding a little on why you feel that he is wrong?

Aaron Z

 

[Sodo]

So when it's UN-plugged, the generator is totally original.

Wrong

He right about this. It's not "totally original". I am interested in whether it's "wrong" (other than morally).


:laughing: :laughing: I made a mistake once (thought I was wrong, but I was right). :laughing: :laughing: