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

[Sodo]

My welder has a 3-prong plug, the generator has a 4-holer. I guess someday I'll make an adapter but today I want to weld so the only way is to put a 3-hole outlet in the 4-hole generator.

I have two questions:

1) Can I do this?

2) What do I do with the gray wire? Can I simply isolate it?

 

[oldnslo]

Does the green / yellow go to frame ground while the grey attaches to a terminal ground? I believe they are both grounds but not sure how they are connected to the generator and if not using one will mess up the electronics in some fashion.

 

[davesl708]

Hi. I would not recommend wiring from 4 to 3. But if you are so inclined you can just swap out the plug. the (gray)white wire should be neutral, just tape it off and leave it in the box. the reason for the 4 wire plug is so that appliances can use the neutral from the circuit box to tap off half the 220v and get 110v for internal motors or controls. That is not needed for a welder.

 

[Sodo]

Ok I will isolate the gray wire.

 

[davesl708]

Just remember if you use the gen for equipment that need the neutral you will need to change it back.

 

[George2615]

In your pics you show the 4 prong receptacle wiring as red/black/gray/green w/yellow. The red & black are the hot leads, gray is neutral and green / y is ground.
Temporarily connect the red /black /and green w yellow to your 3 hole receptacle and wire nut and tape off the gray.
Later after you reconnect the 4 prong outlet, make an adapter with a 4 prong male to 3 prong female to plug in the welder. Just don't use the gray wire in the adapter.

 

[Dave M7040]

Most generators have a label affixed to them that say "Neutral bonded to frame" or "Neutral not bonded to frame." For portable generators it is usually the former while for permanent backups like Generac sells the neutral is not bonded. You need to be certain you have not compromised this by taping off the grey.
Do you see any wire connected to the bare frame of the generator usually with a proper lug and screw into the frame.
If you are not familiar with the bonded vs unbonded or floating this link may help.
GenTran Accessory for Neutral Bonded Generators

What does yours say?
Dave M7040

 

[Industrial Toys]

The generator will actually like this arrangement as it will run perfectly balanced leg to leg. I run all my generators into an auto transformer when feeding the buildings 110/220 so all the gensets see is a nice balanced 220 load.

 

[Sodo]

Dangit Dave I didn't chase down the gray wire, just taped it off and put it all together, so I could get back to my welding project. I agree the generator should be restored to 4-wire. I'll probably add a 3 wire (50R) outlet (in its own box, but tapped off the terminals of the 4-wire) if I can find a space for it.

All done, generator's running the welder now. Thanks for all the help.

 

[Industrial Toys]

Why not make a nice conversion/adapter cable for future use?

 

[Sodo]

Like a dongle? Then I have to buy a plug too, and a section of cord. I will do that if I can't find a good place to hard-mount the box. I'd like to have both on the generator (3-holer and 4-holer).

 

[Industrial Toys]

I have made up a bunch of adapters like that over the years. If you are going to do that, try and avoid plugs or receptacles that are made of bakalite or such similar material. You drop it once and the things break. Certain Leviton stuff is really bad for that.

 

[Jim in ICT]

The generator puts out single phase, correct? Could this be a universal receptacle that accepts both types of single phase plugs?

 

[Tractor Seabee]

Your Gen Set should work fine on a 240 single phase with no neutral. Looks like that is a 30 Amp Receptacle; is that right? Just get a 4 wire Dryer cord and replace the one on your welder and tape off the neutral. If it is 50 Amp get a 4 wire Range cord and do the same. That is what I did so now it works anywhere. I also have made many adapter cords to use various things in various ways. Not hard to do. The yellow plastic cord ends available at RV stores are practically indestructible. I like the twist lock type, which your Gen Set has over the standard pushin for 20 and 30 Amp. I bought RV extension cords for my Gen Set also. Prices are better at the big box stores than at RV dealers also.

Ron

 

[Sodo]

Most generators have a label affixed to them that say "Neutral bonded to frame" or "Neutral not bonded to frame." For portable generators it is usually the former while for permanent backups like Generac sells the neutral is not bonded. You need to be certain you have not compromised this by taping off the grey.
Do you see any wire connected to the bare frame of the generator usually with a proper lug and screw into the frame.
If you are not familiar with the bonded vs unbonded or floating this link may help.
GenTran Accessory for Neutral Bonded Generators

What does yours say?
Dave M7040

Thank you Dave this is the answer and the link you provided is a good one.

Why not make a nice conversion/adapter cable for future use?

OK IToys, it's looking like the Dongle would have been the better option, where within the dongle, the neutral is bonded to ground. And when the dongle is unplugged, then the Generator is back to a GFCI-compatible unit (which I don't need but,,,). This is easy if dongle outlet box is bolted/grounded to the generator - but its 4-wire supply can be unplugged to access the ORIGINAL 4-prong outlet, which will then un-bond the neutral.

Pretty simple, and is the GOOD way. Not sure when I can get to it.

 

[Gary Fowler]

My welder has a 3-prong plug, the generator has a 4-holer. I guess someday I'll make an adapter but today I want to weld so the only way is to put a 3-hole outlet in the 4-hole generator.

I have two questions:

1) Can I do this?

2) What do I do with the gray wire? Can I simply isolate it?

I recently burned up a transfer switch on my motorhome when plugging it in to a 4 prong 50 Amp outlet that I was using for my welding machine (220V). After removing the welding machine plug from the wall, I found that it was wired exactly like your photo (black, red and ground but with the grey missing) so it was only using 2 hot and a ground with the grey prong not attached to anything. It works fine for my 220v welding machine but sure let a lot of smoke out of my motorhome electrical box. My motorhome required the grey neutral wire to be hooked up thereby making two 110V legs of 25 amps each rather than 220v. Many electricians have made the mistake of wiring in 220v to a 4 prong outlet (like my welding machine hookup) and hooking it to their campers 50 amp service 4 prong power cord.
I cant explain it as to how it works because it measures 110v in both hot legs when going from red to green and black to grey buy you don't get 220v in the camper. Must be something in how they are wired.

 

[Sodo]

I hear ya. Gonna get this dongle hooked up so it's back to normal on the 4-holer, and Neutral-bonded when the 3-holer is hot. And in the meantime won't plug anything that 3-holer but the welder.

 

[Arc weld]

Couldn't copy a link but all you need is a Miller full KVA adapter cord (4 pin male by 3 pin female), part #300517.

 

[Sodo]

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.

 

[BukitCase]

If you get lazy...
miller4less.com

...Steve

BTW, they are usually cheaper on anything Miller - only downside is their site sucks, can't find SQUAT without a miller pn#...