220 volt wiring.

[Phil Tibbetts]

I was wanting to feed my mig welder from the generator so I could use it away from hydro power.

 

[John T]

Phil, another good question, have you read and figured out my explanation and answer below ???

Okay so if I want to make up a 4 prong plug to plug into my generator with a 3 prong welder receptacle on the other end how do I wire the plug and most important the welder receptacle?

THE ANSWER DEPENDS

1) First of all are you sure your genset actually produces 240 VAC which is available at perhaps its Three Pole Four Wire (thats 4 pins) Receptacle ????????????????????????????????????????????????????? and does it have adequate current rating ??? Many Buzz Box 240 Volt welders plug into a 50 Amp 240 Volt Receptacle (Two Pole Three Wire Grounding has 3 pins Hot Hot Ground)

2) If so and you need 240 VAC to power the welder which has a 3 conductor cord designed for Two Hots L1 & L2 at 240 Volts PLUS an Equipment Ground

You feed Three wires IE two Hots L1 & L2 PLUS the Ground (NOT the Neutral) on the Gensets receptacle to a (50 Amp I presume) Two Pole 3 Wire Grounding (thats 3 terminals) Receptacle into which you plug the welder. You can make this yourself with a Plug for your genset and a receptacle for the welder or perhaps a dogbone converter is available???????????

Use the Two Hots PLUS the Ground out of the gensets receptacle to wire up/convert for your 240 Volt welder receptacle THATS EASY PEASEY you can do this provided your genset has 240 and adequate amps to feed your welder.. A typical 240 volt welder receptacle uses 3 wires, 2 hots and a ground and you can get those three wires out of your gensets 4 terminal receptacle PROVIDED it has 240 ???????

Got it ??????? Post back any questions YOU GOT THIS piece of cake lol

John T Live in the RV in Avon Park Florida headed tomorrow to Florida Flywheelers where I exhibit, show starts next Wednesday

 

[John T]

Rich, you state You can use either the neutral or ground

Do as you please (and even if it can work) but I would use the GROUND instead of the Neutral to feed a 240 Volt Welder. Ground (often Bare/Green) is ONLY for fault current while Neutral (White) is for normal 120 VAC return current. If his welder is straight 240 ONLY it wouldn't need or use a Neutral but would use a safety Ground and L1 & L2 for the 240 (provided thats what he has??)

Best wishes Rich take care now

John T

 

[MarkB_MI]

I would tie the ground and neutral from the four-wire outlet together and run that to the ground pin of the three-wire welder plug. That ensures that a short to the welder chassis will fault the generator's circuit breaker.

 

[John T]

Phil, FYI if it applies or may help you understand (there may be some confusion below) THERE CAN BE ONLY ONE NEUTRAL GROUND BOND. Once its established DO NOT DO NOT bond them again later downstream...

If you wire up a 4 pin (3 Pole 4 Wire Grounding) Plug for your genset and a 3 pin (2 Pole 3 Wire Grounding) Receptacle for your welder, use the two Hots (Typical Red n Black 240 across) and the typical Bare/Green Equipment GroundING Conductor (NOT Neutral) DO NOT re bond (if already established) Neutral and Ground
again.......

John T

 

[MarkB_MI]

> Phil, FYI if it applies or may help you understand (there may be some confusion below) THERE CAN BE ONLY ONE NEUTRAL GROUND BOND. Once its established DO NOT DO NOT bond them again later downstream...

> If you wire up a 4 pin (3 Pole 4 Wire Grounding) Plug for your genset and a 3 pin (2 Pole 3 Wire Grounding) Receptacle for your welder, use the two Hots (Typical Red n Black 240 across) and the typical Bare/Green Equipment GroundING Conductor (NOT Neutral) DO NOT re bond (if already established) Neutral and Ground again..... .

John, which is the worse scenario: Multiple neutral-ground bonding points or no bond at all? I think you will agree that the latter is more serious: With no neutral-ground bond, a short-circuit from hot to ground will not fault a circuit breaker. In this particular case, it would leave the chassis of both the welder and generator HOT.

You and I are proposing the same basic solution: A short harness with a 240V four-wire plug at one end and a 240V three-wire receptacle at the other. Where we depart is how to connect the neutral of the four-wire plug: You say to leave it disconnected while I say to tie it to the ground conductor. Tying them together ensures that a hot-to-ground short-circuit will fault the generator's circuit breaker. Using your solution, the circuit breaker will fault only if there's a neutral-to-ground bond inside the generator.

Do 240V generators typically have an internal bond between neutral and ground? I honestly don't know, and my generator is a thousand miles away right now, so I can't check it. But even if the generator has an internal bond, is it such a bad thing to have a second bond a few inches away?

Building a cable as I describe roughly mirrors the situation I have at my home: I have a four-wire cable that runs from the generator to my service disconnect/transfer switch panel. Inside the SD/TS panel, neutral and ground are bonded. If there's another bond inside the generator, I don't see how it is likely to cause an issue. But removing the bond inside the service disconnect would be a BIG NO-NO.

 

[John T]

Mark, you ask: John, which is the worse scenario: Multiple neutral-ground bonding points or no bond at all? I think you will agree that the latter is more serious:

SORRY NOOOOOOOOOO BUT WITH ALL DUE RESPECT I DO NOT AGREE

You are free to your own opinion WITH ALL DUE RESPECT, to each their own, HOWEVER I DO NOT agree and that's in accordance with MAYBE HALF THE GENERATORS PRODUCED (HAVE NO BOND AT ALL) and all the NEC workshops and seminars I attended over my years of practicing power distribution ! Perhaps generator manufacturers who sell gensets WITH NO BOND AT ALL (which are many) are willing to risk injury to buyers I THINK NOT

As an Attorney and an Engineer I just don't envision manufacturers of Generators selling them to the public NOT BONDED (which many indeed are) if that was hazardous, ever hear about the legal theory of STRICY LIABILITY Yikes Imagine all those people buying small portable gensets that come from the factory WITH NO BOND you think if that was hazardous their corporate attorneys would let them out the door ????

There is a place/application where a Genset should be Bonded and place/application where it should NOT. I understand that and could explain it but NOT in a few sentences here yet will try my best to help you if I can. Very briefly FYI multiple NG Bonds can result in the Equipment GroundING Conductor becoming a hot live current carrier and its in contact with outer cases/frames of tools and appliances which you touch and your body could then become another parallel current carrier and as little as 0.050 amps in your heart can cause fibrillation and kill you dead THATS WHY I BELIEVE MULTIPLE NG BONDS TO BE MORE HAZARDOUS THAN A GENSET (of which MANY are) THAT HAS NO BOND AT ALL

BOTTOM LINES: A Cardinal Rule I was taught WAS THERE CAN BE ONLY ON NEUTRAL GROUND BOND,,,,,,,,,,,Gensets come from the factory Bonded others not Bonded,,,,,,,,,,Its my professional opinion multiple Neutral Ground Bonds can be more hazardous than no Bond at all

Of course there can be rare conditions and circumstances where bonding or not bonding can make a difference and its best one way or the other ANYTHING CAN HAPPEN MURPHYS LAW GRRRRRRRRRR

But in the meantime I must advise people NOT TO MAKE MULTIPLE NEUTRAL GROUND BONDS AND UNBONDED GENSETS ARE NOT ALONE HAZARDOUS (It depends on the application)

Given enough time I could explain how when where and why a Genset should be bonded,,,,,,,,,When it should NOT,,,,,,,,,When connection to a Grounding Electrode is required,,,,,,,,,,When it is not required etc but thats beyond the scope of this.

Hope this helps you understand. Best wishes to you Mark, take care and God Bless you and yours

PS heres the answer to another of your questions:

Do 240V generators typically have an internal bond between neutral and ground?

Some gensets are bonded others NOT. If I can find it I have a list of genset makes that tells which are which

John T BSEE,JD Retired Electrical Power Distribution Engineer

 

[MarkB_MI]

Thank you for your response, John. I still would tie the neutral and ground together in a four-to-three wire generator adapter. That would make it equivalent to how I have my home transfer switch wired.

 

[John T]

You're most welcome, glad to help. Hey I support anyones right to wire or configure THEIR Generator however THEY well please, I figure its THEIR right, THEIR risk, THEIR choice.......

Take care now and have a good one !!!!!!!!!

AS PROMISED here is a list (no warranty as to its accuracy) showing which Generators come from the factory WITH NO bond (IE Floating) and those that ARE BONDED..Which to use when/where or how to configure or how to create a Bond if not so equipped would take a lot more explanation !!!!!! In addition OSHA has their own set of rules regarding portable gensets used on construction sites, get this THEY WANT THEM BONDED BUT NOT GROUNDED as best I recall again no warranty, things/codes may have changed since I retired

Just remember the basic general rule THERE CAN BE ONLY ONE NEUTRAL GROUND BOND

John T Live from the Florida Flywheelers here until next Monday in Row 74 far Northwest corner of exhibit field stop n say howdy. Back again in February Good Lord willing
Bonded or Non Bonded Gensets

 

[Dusty MI]

John,

We are at Zephyrhills, FL. until sometime in March.
Dusty

 

[John T]

Im at Fort Meade now.....We like Zephyrhills, had that bad experience however there last month when my wife
had given blood earlier but passed out in the Zephyrhills Moose and the ambulance took her to the hospital
in Plant City......Im not sure if we get back that way this season but will give you a shout if we do

Nice talking to you Dusty

John T

 

[MarkB_MI]

> AS PROMISED here is a list (no warranty as to its accuracy) showing which Generators come from the factory WITH NO bond (IE Floating) and those that ARE BONDED.

It looks like our Honda EM6500 has a bonded neutral. Interestingly, the EU6500 inverter-based generator has a floating neutral. I'm guessing the difference is because the EM6500 is marketed as a contractor generator, while the EU6500 is marketed for home backup.

> John T Live from the Florida Flywheelers here until next Monday in Row 74 far Northwest corner of exhibit field stop n say howdy. Back again in February Good Lord willing

I don't expect to make it over there this time, but thanks for the invitation.