"ground"

[mechanic416]

"Ground", I hear this term a lot on all the forums welding, automotive, etc. and a lot of the time its not used in the proper context.

I am not going into all the technical terms of what, when and why but this should help people understand.

Electric systems AC uses a ground you have power wires and ground wires. If for some reason you lose your ground you lose your power.

DC power systems use positive and negative there is no ground. Like the battery in your car or truck lose the positive or negative its dead won't start or nothing in it will work.

Now as far as welders and plasma cutters there is a ground. The ground is on the inside and is used to ground everything machine case, PCB,s, etc. to the AC power system.

The cable with the clamp on it that you put on the metal to be welder or cut is "NOT" a ground. It is the work cable and clamp, it goes to the work piece (metal). The work cable and clamp can be positive or negative depending on the process being used as DCEP or DCEN.

Now it is recommend by a lot of welding and plasma cutter makers to ground the unit to the welding table or cutting table this is done with a wire say 10 gauge or what ever is recommend in the manual from the unit case screw or ground terminal to the table or even the building if its metal.

I know we all have been using the word ground. But maybe the next time you may thing about what you really mean when say did you "GROUND"
it.

[Flat_Bastard]

Electric systems AC uses a ground you have power wires and ground wires. If for some reason you lose your ground you lose your power.

I hate to be pedantic, but if you want to educate folks.

In AC systems you have, current "carrying conductors" ("hots"/black, red(120/240v 1phase), blue for 120/208V 3 phase, and brown, orange, yellow for 120/208v 3 phase and up), "grounded conductor" ("neutral"/white 120/240V 1 phase, gray 120/208V 3phase and up), and the "ground conductor" ("ground"/green 1phase/3phase).

If you loose the grounded conductor, you no longer have a path back to ground, or an open circuit. So no path for the electrons to flow.

If you loose the ground conductor, you still have a closed circuit, and a path back to ground. So the electrons will still flow.

In a balanced 240V circuit you don't need the grounded conductor for a return path. But if your machine has anything inside that runs off of 120V (think, the clock on your oven/range) you do need the grounded conductor, for the return path. So loosing your grounded conductor may very well shut the machine down. Though I am unaware of any welding/cutting machines setup like this, but I'm sure there are some out there.

[mwshaw]

Automobiles in the early 50's were positive ground 6 volt systems. Meaning the positive cable on the battery was connected to the car frame and body. In the later 50's everything changed to 12 volt, negative ground. What this allowed is that only one wire had to be run to any electrical load to supply power and then the other side of light bub, radio etc was just connected to ground, the metal chassis of the car. Ground is not the same as neutral in a 120/240 electrical service, ground is a safety protection to keep any voltage/current to be available to shock/kill the un-insulated animal, human or otherwise. Neutral wires are current carrying conductors and should not measure any voltage but complete the circuit to provide 120 volt current to use. Neutral wires should not ever show voltage as they should be bonded to ground, plumbing, ground rods and system neutral supplied by power company. Any time a neutral has voltage to ground, its connection to the power company is defective and can cause a lot of damage as 120 volt phases are not equal and could show anywhere from 0 to 240 volts depending on how bad the connection is. This condition is called a floating neutral meaning it can change depending on what is connecting on the circuit. IF the ground is not bonded in an older three wire 240 volt appliance can energize the ground and create a shock hazard on any ground connector in any wall plug. For instance a 240 volt dryer on three wire, could energize the ground as it's motor is designed to run on 120 volt, one phase to neutral , heating elements are connected to both phases and run on 240 volts . This is the reason code now is 4 wire appliances with both current carrying neutral and safety ground as separate wires.

[Insaneride]

This video explains open or floating neutral




Ground is a term used loosely for return path. Usually understood but not always used correctly. As mentioned, 240 volts ac doesn't need a ground but is required for safety any phase. Sometimes it gets used as a neutral for return on 120 volts ac but as the video shows, it can cause problems.

Grounding a weldin bench is a bad idea turning your whole building grounding into the welding circuit. Example: connecting work lead to building ground makes every grounded device on that circuit part of weld circuit. A grounded air compressor wether 120v or 240 volt will light up if the stinger or torch inadvertently comes in contact.

[mechanic416]

Automobiles in the early 50's were positive ground 6 volt systems. Meaning the positive cable on the battery was connected to the car frame and body. In the later 50's everything changed to 12 volt, negative ground. What this allowed is that only one wire had to be run to any electrical load to supply power and then the other side of light bub, radio etc was just connected to ground, the metal chassis of the car. Ground is not the same as neutral in a 120/240 electrical service, ground is a safety protection to keep any voltage/current to be available to shock/kill the un-insulated animal, human or otherwise. Neutral wires are current carrying conductors and should not measure any voltage but complete the circuit to provide 120 volt current to use. Neutral wires should not ever show voltage as they should be bonded to ground, plumbing, ground rods and system neutral supplied by power company. Any time a neutral has voltage to ground, its connection to the power company is defective and can cause a lot of damage as 120 volt phases are not equal and could show anywhere from 0 to 240 volts depending on how bad the connection is. This condition is called a floating neutral meaning it can change depending on what is connecting on the circuit. IF the ground is not bonded in an older three wire 240 volt appliance can energize the ground and create a shock hazard on any ground connector in any wall plug. For instance a 240 volt dryer on three wire, could energize the ground as it's motor is designed to run on 120 volt, one phase to neutral , heating elements are connected to both phases and run on 240 volts . This is the reason code now is 4 wire appliances with both current carrying neutral and safety ground as separate wires.

You have a positive and negative there is no ground. Its just a term people started using.

[bigb]

I hate to be pedantic, but if you want to educate folks.

In AC systems you have, current "carrying conductors" ("hots"/black, red(120/240v 1phase), blue for 120/208V 3 phase, and brown, orange, yellow for 120/208v 3 phase and up), "grounded conductor" ("neutral"/white 120/240V 1 phase, gray 120/208V 3phase and up), and the "ground conductor" ("ground"/green 1phase/3phase).

If you loose the grounded conductor, you no longer have a path back to ground, or an open circuit. So no path for the electrons to flow.

If you loose the ground conductor, you still have a closed circuit, and a path back to ground. So the electrons will still flow.

In a balanced 240V circuit you don't need the grounded conductor for a return path. But if your machine has anything inside that runs off of 120V (think, the clock on your oven/range) you do need the grounded conductor, for the return path. So loosing your grounded conductor may very well shut the machine down. Though I am unaware of any welding/cutting machines setup like this, but I'm sure there are some out there.

Agreed except for the one you call the "ground" conductor is technically the "grounding" conductor. That's all I can say without risking the secrecy of the secret electrician's terminology lingo.

[FlaJoe]

You have a positive and negative there is no ground. Its just a term people started using.

The proper term is "chassis ground". In electronics there's even different symbols for a chassis ground and an earth ground. Old radios and TVs frequently had both and they usually weren't tied together. The earth ground was used as the return path for the antenna (and often connected to a steel water pipe in the house) and, all too often, they used the chassis as the return path for the AC power and the chassis would be tied directly to one side of the AC power plug. They nearly always used a two wife AC plug with no "ground" as we know it in AC power systems today. With the old two wire power systems, if you turned the power plug half way around it would tie the chassis to the hot side of the AC line. If you touched the chassis or it it had metal knobs you would got a tingle. If you were wet or bare foot or touched another metal object at the same time you could get quite a jolt!


An automobile isn't tied to "the ground" so using the term "ground" when referring to an automobile electrical system is just nonsense but it's long been commonly called that, regardless of the polarity.

*Tying the earth ground and chassis ground together in radios and TVs isn't a good idea. It usually introduces more electrical noise into the received signal. However, it is cheap so many later model radios and most TVs did that before the days of three wire AC power plugs.

[ronsii]

The proper term would "chassis ground". In electronics there's even different symbols for a chassis ground and an earth ground. Old radios and TVs frequently had both. The earth ground was used as the return path for the antenna (and often connected to a steel water pipe in the house) and, all too often, they used the chassis as the return path for the AC power and the chassis would be tied directly to one side of the AC power plug. They nearly always used a two wife AC plug with no "ground" as we know if in AC power distribution today. With the old two wire power systems, if you turned the power plug half way around it would tie the chassis to the hot side of the AC line. If you touched the chassis or it it had metal knobs you would got a tingle. If you were wet or bare foot or touched another metal object at the same time you could get quite a jolt!

Oh yeah!!!!, remember it all too well I still work on a lot of old stuff like that.

[Willie B]

I hate to be pedantic, but if you want to educate folks.

In AC systems you have, current "carrying conductors" ("hots"/black, red(120/240v 1phase), blue for 120/208V 3 phase, and brown, orange, yellow for 120/208v 3 phase and up), "grounded conductor" ("neutral"/white 120/240V 1 phase, gray 120/208V 3phase and up), and the "ground conductor" ("ground"/green 1phase/3phase).

If you loose the grounded conductor, you no longer have a path back to ground, or an open circuit. So no path for the electrons to flow.

If you loose the ground conductor, you still have a closed circuit, and a path back to ground. So the electrons will still flow.

In a balanced 240V circuit you don't need the grounded conductor for a return path. But if your machine has anything inside that runs off of 120V (think, the clock on your oven/range) you do need the grounded conductor, for the return path. So loosing your grounded conductor may very well shut the machine down. Though I am unaware of any welding/cutting machines setup like this, but I'm sure there are some out there.

It still isn't ground. It is grounded. At the transformer, and again at the service disconnect the center tap conductor is connected to earth ground.

Without that connection to earth, it'd still work. In single phase systems all three conductors connected to the transformer winding are live. the center tapped conductor carries only the imbalance of the current, but make no mistake, IT IS LIVE! The worst shock of my life was from this center conductor called neutral, or grounded.

[Willie B]

Agreed except for the one you call the "ground" conductor is technically the "grounding" conductor. That's all I can say without risking the secrecy of the secret electrician's terminology lingo.

No secrets, just intentionally confusing. Ground means little. Grounded conductor might be white, or grey. Grounding conductor is green or bare. Been a lot of people confused by that detail.

In a welder neither lead is intentionally connected to earth ground, or utility transformer. Work lead is a better term for less confusion.

Lots of disagreement as to whether a welding table should be connected to earth.

[Insaneride]

No secrets, just intentionally confusing. Ground means little. Grounded conductor might be white, or grey. Grounding conductor is green or bare. Been a lot of people confused by that detail.

In a welder neither lead is intentionally connected to earth ground, or utility transformer. Work lead is a better term for less confusion.

Lots of disagreement as to whether a welding table should be connected to earth.

The factory doesn't intentionally connect ground but some end users insist on it when they intentionally ground welding bench. MILLER suggests it to create a Faraday cage when hi frequency is a nuisance but it just doesn't make sense. Using a 10gauge wire to ground a welding table leaves the 12 or 14 gauge wire in the walls vulnerable . Theoretically, the 12 or 14 gauge could blow open behind the walls with no visible damage or breaker trip. This would leave the circuit using that ground unprotected or un grounded.

[whtbaron]

Ok... while we're on the topic of grounds... I have a question. I'm in a farm yard (240, single phase ) and where the power comes in at the yard pole, there is a ground (literally a galvanized rod driven into the earth). Both houses and three sheds all have grounds (galvanized rods driven into the earth). Some of these rods are getting older and are no doubt corroded /eaten by moisture and electricity. Will the ability of these rods to transmit electricity affect my power availability or my power bill in any way, or are these simply there to accept the power from the green wire ground in the event of a failure? I know I have touched the steel door sill in one shed with the ground from my welder and saw sparks , so I cabled it to the ground rod to prevent that. Now I'm wondering if that was a good move, or is this an indication that it might be time to start replacing those ground rods?

[Willie B]

Driven grounds are primarily to attain equipotential. Imagine a cow. She is chained to a steel stantion, standing on a urine soaked floor, with concrete & rebar. The vacuum line is a conductor, as is the milk pipe, and the water bowl. Lots of conductors! She must be between two conductors to receive a shock. If we connect (bond) all this to everything else, the stray voltage present in most barns is not an issue. In some barns we use a high impedance bond to transformer center tap, others a low impedance to make the conductive surfaces one electrically. It reduces the risk of shock. Cattle are highly sensitive. .1 volt gives them measurable medical symptoms.

Some argue to bond welder table to equipment ground, others say isolate. There will be incidental grounding.

[Insaneride]

Ok... while we're on the topic of grounds... I have a question. I'm in a farm yard (240, single phase ) and where the power comes in at the yard pole, there is a ground (literally a galvanized rod driven into the earth). Both houses and three sheds all have grounds (galvanized rods driven into the earth). Some of these rods are getting older and are no doubt corroded /eaten by moisture and electricity. Will the ability of these rods to transmit electricity affect my power availability or my power bill in any way, or are these simply there to accept the power from the green wire ground in the event of a failure? I know I have touched the steel door sill in one shed with the ground from my welder and saw sparks , so I cabled it to the ground rod to prevent that. Now I'm wondering if that was a good move, or is this an indication that it might be time to start replacing those ground rods?

It sounds like your ground rods are there for a ground fault/safety. There shouldn't be any current flowing thru them at all. I don't see how it could effect your bill unless there's some leakage from an appliance or whatever to ground.

As for your door; its grounded. Was your work clamp connected to grounded work bench because what you described is exactly why I say it's a bad idea to connect your weld bench to mains ground. Good thing you didn't hit a compressor.

Seriously people, why do you need your weld bench connected to your main electrical ground?

[whtbaron]

I'm aware of the stray voltage issues but I'm out of livestock (5 cats and a dog and the old lady is not receptive to the milking machine attachments) so that isn't an issue. I'm more concerned with maintaining effective voltage and not paying for more than I have too. I didn't connect the welder's working ground or the bench to the door frame, I connected the building's ground rod into the earth to the door frame. Still a bad idea? My bench is metal and sits on the concrete floor about 8 ft away from the building's ground rod. The sparks occur if I accidentally drag the welder's ground clamp across the door sill, and also occurred when I was connecting the door sill to the building's ground rod. If there was a current differential to create that spark, should I be changing the building's ground rod?

[Sedanman]

I had to wrap my head in duct tape to keep it from exploding after reading some of the misinformation presented here.

[Meltedmetal]

I'm aware of the stray voltage issues but I'm out of livestock (5 cats and a dog and the old lady is not receptive to the milking machine attachments) so that isn't an issue. I'm more concerned with maintaining effective voltage and not paying for more than I have too. I didn't connect the welder's working ground or the bench to the door frame, I connected the building's ground rod into the earth to the door frame. Still a bad idea? My bench is metal and sits on the concrete floor about 8 ft away from the building's ground rod. The sparks occur if I accidentally drag the welder's ground clamp across the door sill, and also occurred when I was connecting the door sill to the building's ground rod. If there was a current differential to create that spark, should I be changing the building's ground rod?

I would guess that you have a problem with the wiring on somewhere at your location. your building should not be hot to the ground rods. I'd check the voltages in the various outlets in the building looking for an imbalance between the 2 sides of the split phase and check the neutral to ground in each outlet. Check the voltage from the door sill to the ground rod. Or get a good electrician to check it out soon. Just my opinion and I'm not an electrician so value it accordingly.

[Flat_Bastard]

Agreed except for the one you call the "ground" conductor is technically the "grounding" conductor. That's all I can say without risking the secrecy of the secret electrician's terminology lingo.

Right you are, and thank you.

I proof read my post several times, let it sit for a bit, proof read it again to be sure, hit post.

I better lock those words down in my head if I ever expect to pass these tests.

Secrecy of the secret, hidden in technical jargon, spoken softly between the GC, the Fm, the JW and AHJ.

[Fast Leroy]

I hate to be pedantic, but if you want to educate folks.

In AC systems you have, current "carrying conductors" ("hots"/black, red(120/240v 1phase), blue for 120/208V 3 phase, and brown, orange, yellow for 120/208v 3 phase and up), "grounded conductor" ("neutral"/white 120/240V 1 phase, gray 120/208V 3phase and up), and the "ground conductor" ("ground"/green 1phase/3phase).

If you loose the grounded conductor, you no longer have a path back to ground, or an open circuit. So no path for the electrons to flow.

If you loose the ground conductor, you still have a closed circuit, and a path back to ground. So the electrons will still flow.

In a balanced 240V circuit you don't need the grounded conductor for a return path. But if your machine has anything inside that runs off of 120V (think, the clock on your oven/range) you do need the grounded conductor, for the return path. So loosing your grounded conductor may very well shut the machine down. Though I am unaware of any welding/cutting machines setup like this, but I'm sure there are some out there.

In a couple of the plants I've worked in we had "High Resistance Grounding Systems" where the X0 on the Substation Transformer was connected to ground through a very large resistor that limited the current flow to ground to about 5 amps. If a 3 phase motor shorted to ground a light on the MCC would come on but the breaker for that motor would not trip and the motor would continue to run. This kept a $500 motor from shutting down a $10,000 / hr process. Of course if another phase shorted you had a phase to phase fault and the breaker would trip.

[Insaneride]

I'm aware of the stray voltage issues but I'm out of livestock (5 cats and a dog and the old lady is not receptive to the milking machine attachments) so that isn't an issue. I'm more concerned with maintaining effective voltage and not paying for more than I have too. I didn't connect the welder's working ground or the bench to the door frame, I connected the building's ground rod into the earth to the door frame. Still a bad idea? My bench is metal and sits on the concrete floor about 8 ft away from the building's ground rod. The sparks occur if I accidentally drag the welder's ground clamp across the door sill, and also occurred when I was connecting the door sill to the building's ground rod. If there was a current differential to create that spark, should I be changing the building's ground rod?

Metal buildings and framing including Timely or other metal doors are bonded to electrical mains so that's not a bad idea. What's weird is when you connected the metal jam to the ground rod and got the same sparks. That is spooky. Do you have a metal roof? What are the walls made of? As mentioned, you have a differential. I see your concern of wasted electricity. Not to sound outlandish because what your saying is outa my keyboard commando league but; it maybee possible to discharge it. I would check for potential with all power off. Ok that was outlandish.

Edit: I can't say I've ever seen a door bonded with a shunt but I just thought metal doors were grounded thru metal framing. As mentioned, measure voltage and resistance between door and rod. Use welding leed as a volt meter extension to measure over a distance or discharge. The hi resistance resistor was also mentioned, between ground rod and door???

Btw, the reason I wouldn't use 10 gauge to ground a weld table is; because 12 ,14 and even 16 gauge are typical for 120 volt service. The lighter gauge ground wire is going to burn out first if you stick your stinger to any grounded equipment when the work clamp is on bench.

Grounding a bench doesn't make it a Faraday cage. Bonding a bench is Detrimental to building wiring and serves no useful purpose imvho.


Edit: edit: using a ground wire as a return like the the floating open neutral or whatever you call it carries current thru the ground. Sub panels are not supposed to have neutral bonded to earth ground for that reason. Ground wire should only carry current for a moment during a fault.

Wheatbaron, sounds like you may have an open neutral.

[Willie B]

Metal buildings and framing including Timely or other metal doors are bonded to electrical mains so that's not a bad idea. What's weird is when you connected the metal jam to the ground rod and got the same sparks. That is spooky. Do you have a metal roof? What are the walls made of? As mentioned, you have a differential. I see your concern of wasted electricity. Not to sound outlandish because what your saying is outa my keyboard commando league but; it maybee possible to discharge it. I would check for potential with all power off. Ok that was outlandish.

Edit: I can't say I've ever seen a door bonded with a shunt but I just thought metal doors were grounded thru metal framing. As mentioned, measure voltage and resistance between door and rod. Use welding leed as a volt meter extension to measure over a distance or discharge. The hi resistance resistor was also mentioned, between ground rod and door???

Btw, the reason I wouldn't use 10 gauge to ground a weld table is; because 12 ,14 and even 16 gauge are typical for 120 volt service. The lighter gauge ground wire is going to burn out first if you stick your stinger to any grounded equipment when the work clamp is on bench.

Grounding a bench doesn't make it a Faraday cage. Bonding a bench is Detrimental to building wiring and serves no useful purpose imvho.


Edit: edit: using a ground wire as a return like the the floating open neutral or whatever you call it carries current thru the ground. Sub panels are not supposed to have neutral bonded to earth ground for that reason. Ground wire should only carry current for a moment during a fault.

Wheatbaron, sounds like you may have an open neutral.

I'll concur. An open neutral (a bad spot in the center tap conductor) is the most likely cause of your problem. It'll manifest in imbalance of voltage split on 120 volt equipment. If your lighting is the multivolt electronic variety, you may not have noticed the imbalance. If you had incandescent, half the bulbs would be burned out, the other half dim.

[whtbaron]

It's a wooden structure without much metal... the angle iron protecting the door sill at the concrete is one of the few pieces of structural metal in the building. Not much for outlets either... 5 110 plugins and 2 240's . I'm thinking I'll check the 240's first to make sure they are grounded to the white and not the green, but I'm sure they are. Lighting is just 2 big 200 watt incandescents since the building isn't heated in winter. Hmmm.... possibly the bare ground cable ( to the rod) is touching the circuit to the white grounds in the box? I'll have to look at it closer, but it's been that way for over a year. In the middle of seeding right now.

[walker]

If you are a welder and cant figure out what somebody means when they say your ground clamp came off, then you have troubles. Improper terminology sure, but becomes proper terminology when used that way for a hundred years.

[Willie B]

If you are a welder and cant figure out what somebody means when they say your ground clamp came off, then you have troubles. Improper terminology sure, but becomes proper terminology when used that way for a hundred years.

I've always believed there would be less fouling up the grounded, and grounding conductors in premise wiring if we used different names for them. Then, when welders call one lead ground it implies that it too is the same. They are three different things.

[walker]

I've always believed there would be less fouling up the grounded, and grounding conductors in premise wiring if we used different names for them. Then, when welders call one lead ground it implies that it too is the same. They are three different things.

True, but you are not generally wiring a house and welding at the same time.