# Wondering if someone can look at my grounding



## mkeller (Mar 20, 2014)

see below


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## mkeller (Mar 20, 2014)

mkeller said:


> Hooking up my vm. I have 220 going to my 20 hp rotary phase converter going to my vm.
> At the power box 220 white is grounded.
> I drove a 8 foot copper rod in the ground at the phase converter and grounded the convertor panel and generator.
> generator wiring white ground goes to panel and ties into ground rod wire.
> ...


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## Tony Wells (Mar 20, 2014)

The condensed answer, if I understand your question correctly, is that earth ground and bonding to the neutral only is permitted at the service panel. Equipment ground, like to a frame or chassis is done at the machine, but not with the neutral. The neutral can be a current carrying conductor in some cases, and positively is in others and should never be connected to the machine frame or chassis. It may seem counter intuitive, but electrically, the earth ground and the neutral are only at exactly (hopefully) the same potential at the service panel only. That is even if they are two separate wires in the same conduit running from the same box to the same equipment. The ONLY point where they are common is at the entrance panel.

Now all the real electricians can correct me and explain in more detail.


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## xalky (Mar 20, 2014)

Tony is correct in his description of the neutral and ground should only tie together back at the main service entrance or sub panel. The bare copper wire or Green sheathed wire should be designated as your ground wires for bonding boxes and machinery.

In your photo, you are showing the ground wire hooked up as your third leg on the 3ph circuit. For safety sake change that. This probably means that you'll have to change it at both ends of your wire. The white wire should be carrying voltage in a 3ph circuit. Whit only carries neutral in a single phase circuit. Neutral is not used in a 3ph circuit.

Marcel


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## Dave Smith (Mar 20, 2014)

The main entrance service panel from the power company is the only place that white(neutral) wires are connected to the ground--in all other sub panels and on machines-- neutral wires have their own separate bar and the screw to connect the neutral to the box is removed and the grounds have their own bar--neutrals are always kept separately from the ground wires and carry any voltage back to the main panel only---hope this clears it up for you---any ground rods would only be connected to the grounding wires------Dave
**I agree with Marcel that in three phase the white wire is used as the third leg of power.


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## jim18655 (Mar 20, 2014)

It looks like non-metalic sheathed cable feeding the converter control box. That should have had a bare ground wire in it that should be connected to the equipment ground terminal at the converter and the ground or ground/neutral bar in the service panel depending on how your service is arranged. Do not connect the white neutral wire to the frame of the machine as it could create an unsafe condition. Shocks or fires are possible. The ground rod you installed must also be connected to the equipment ground. You can't just drive a ground rod and use it as a ground without bonding it to the service ground. The earth has too much resistance to reliably carry fault currents or protect you from a shock. Shocks are caused by a difference in potential between two points not necessarily voltage. Also *NEVER* use the green as a current carrying conductor. Tape the white wire blue or better yet cover it with shrink tube. If that is the "manufactured" phase it is supposed to be identified with it's own color by code similar to using orange on the "high" leg of a 240v delta service. Connect the green in that cable to the frame of each machine or grounding lugs in the cabinets.


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## rdhem2 (Mar 21, 2014)

After I read all the posts three times through to be sure of what I was reading I must remark, all you guys trying to help Mkeller are correct.  Well correct in your own way and intentions best I can tell.

Let me throw a term at you electricians use to separate out what you are trying to say so they can understand it. *BONDING*.  *Bonding* is the term used when you make physical hard wire connections to ensure the electrical path to ground through devices in the path to the point of ground.  When the fellow connected to the ground rod at the RPC he bonded it, not grounded it.  When you join two enclosure together with ground wire, grounding locknuts, or grounding bushings you are *BONDING* the enclosures together not grounding them.  The neutral bar in the main service panel is *BONDED* to the enclosure.  Use this term to explain what you are up to and any electrician you talk to will know exactly what you are talking about.  This applies to the point that each of you was trying to make in your own way.

BOY!  I used to take for granted the green wire was either connected to a grounding point or hanging free so never checked it for voltage.  After seeing this I will change my habits.  I ALWAYS check for the presence of voltage on anything I intend to lay my pinkies on.  I always say "I would not even trust my mother if she said the circuit is off!"  Yes, definitely, identify that white conductor and disconnect that green one from the disconnect lug.  Remember the other end too!

One last nit pick.  A five wire circuit is rather common place.  Mostly in industrial establishments.  Three phase conductors, neutral, and ground. Cords, cord ends, plugs, receptacles etc are all readily available from the electrical supply warehouse.  Common configurations 480/277v Wye, 240/120v Delta, and 208/120v Wye. The good book clearly (almost) lays out the use and application of this type circuitry.

You can not ground anywhere you choose as you will create ground loops which will cause more trouble then anyone needs.  This is when the electricity, as usual, takes the path of least resistance to ground and that may not be the electrical system ground.  If you are working in a panel that does not have a meter directly ahead of it, you are more than likely in a sub-panel and the neutrals and grounds shall remain separated.  Only in the service entrance panel do they come together.

Confused enough for one night?  Good, my work is done.


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## mkeller (Mar 21, 2014)

Well i guess we know why im a tool and die maker and not an electrician.   I will go back to square one. with a little more help from the site here.   
My power is a 200 amp service to my house and a wire runs underground to my shed to a smaller service box.
heres the shed service box
wire running the machine is the top right




The shed had existing 220 wire run


So first new question, Is the 220 wire correct for what im doing?  its probaly 30 35 feet long. Should it be in conduit(sp)  I would like to do this correctly(without paying a professional)

if it is ok then question 2
how should i hook it up to L1 and L2

going to call the rotary phase people as well and see if they can help.
Thanks again and your welcome for the noobie humor
Mike

- - - Updated - - -


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## John Hasler (Mar 21, 2014)

If your shed is a seperate building the panel there is a service entrance and should be bonded and grounded as such.

If you use a white wire to carry voltage mark it at both ends.  I like to color all exposed parts of the wire with magic marker.  You want to minimize the risk that someone in the future will mistake it for a grounded conductor.


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## rdhem2 (Mar 21, 2014)

Good Sir:
From the pictures in your post of the sub panel in your shed you need to move a few wires.  Get a separate ground bar from SqD.  It will look just like the neutral bar sans the insulating block.  Screw this ground bar directly to the box.  Scraping paint off the box where the bar lands is good practice also.  Now move all the bare wires from the neutral bar to the ground bar.  Include the big green wire, where ever it comes from.  Check to see that there is NOT a screw going through the neutral bar into the enclosure.  If there is, remove it.  This is what is called the neutral bonding screw and should only be installed in a main service entrance panel.  All other places the grounds and neutrals must be kept isolated from each other.

The neutral is the electrical ground and carries the unbalance in the circuit between the phase conductors.  The ground is the equipment safety ground and is only meant to carry fault current for indefinite short periods of time.

Have FUN, be SAFE!


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## John Hasler (Mar 21, 2014)

rdhem2 said:


> Good Sir:
> From the pictures in your post of the sub panel in your shed you need to move a few wires.  Get a separate ground bar from SqD.  It will look just like the neutral bar sans the insulating block.  Screw this ground bar directly to the box.  Scraping paint off the box where the bar lands is good practice also.  Now move all the bare wires from the neutral bar to the ground bar.  Include the big green wire, where ever it comes from.  Check to see that there is NOT a screw going through the neutral bar into the enclosure.  If there is, remove it.  This is what is called the neutral bonding screw and should only be installed in a main service entrance panel.  All other places the grounds and neutrals must be kept isolated from each other.
> 
> 
> Have FUN, be SAFE!



His shed is a seperate building.  That means that the panel in it is the building service entrance and must be bonded and grounded, with its own ground rod.  He should not remove the bonding screw.


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## jim18655 (Mar 21, 2014)

Check 250.32 Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s)
I don't want to quote what may be copyrighted material but that isn't always the case. If there is a ground run with the feeders then it is not bonded to the neutral at the remote building and is required to have a grounding electrode at the building. There are few exceptions if the feeder was installed under previous versions of the code without a grounding conductor. 
250.32 (B)(1) now require a grounding conductor to be installed with the feeder.
NFPA 2011 Latest version I have at home.

I can't tell from the pictures which way his panel is fed.


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## John Hasler (Mar 21, 2014)

jim18655 said:


> Check 250.32 Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s)
> I don't want to quote what may be copyrighted material...



Quoting a brief passage to illustrate a point is fair use.  See http://en.wikipedia.org/wiki/Fair_use


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## Dave Smith (Mar 21, 2014)

John Hasler said:


> His shed is a seperate building. That means that the panel in it is the building service entrance and must be bonded and grounded, with its own ground rod. He should not remove the bonding screw.




John--if he is bringing in a neutral from his main panel(near meter) it is a sub panel--- then I would not connect it or bond it with the grounds--neutral bar should not be bonded and ground wires should be on separate bar---Dave


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## rdhem2 (Mar 21, 2014)

jim18655 has it nailed.  Perfect reference too.  I was and still am under the assumption that the shed's panel is a sub panel fed from the house main service entrance panel.  Why would you separate the grounds and neutrals then leave the bonding screw installed?  Where is the power company metering located?  The first disconnecting means after the metering equipment is considered the main service entrance gear.

The latest code interpretations say you must include a ground wire in the run to a separate building and also drive two ground rods not closer than six feet apart.  That is the way the lords of Washington State enforce it. So may it be!

I don't write this stuff I only read it and try to understand it.  As Dad always said "The code is a book written by lawyers for lawyers to understand.  Just learn to use it, but don't waste your time trying to memorize it, because in a couple years they will  change it anyway."

You may disregard me but pay attention to *jim18655*.

Stay safe, have fun.


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## jim18655 (Mar 22, 2014)

John Hasler said:


> Quoting a brief passage to illustrate a point is fair use.  See http://en.wikipedia.org/wiki/Fair_use


  250.32 Buildings or Structures Supplied by a Feeder(s) or Branch Circuit(s). (A) Grounding Electrode. Building(s) or structure(s) supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with Part III of Article 250. The grounding electrode conductor(s) shall be connected in accordance with 250.32(B) or (C). Where there is no existing grounding electrode, the grounding electrode(s) required in 250.50 shall be installed. Exception: A grounding electrode shall not be required where only a single branch circuit, including a multiwire branch circuit, supplies the building or structure and the branch circuit includes an equipment grounding conductor for grounding the normally non–current-carrying metal parts of equipment. (B) Grounded Systems. (1) Supplied by a Feeder or Branch Circuit. An equipment grounding conductor, as described in 250.118, shall be run with the supply conductors and be connected to the building or structure disconnecting means and to the grounding electrode(s). The equipment grounding conductor shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The equipment grounding conductor shall be sized in accordance with 250.122. Any installed grounded conductor shall not be connected to the equipment grounding conductor or to the grounding electrode(s). Exception: For installations made in compliance with previous editions of this Code that permitted such connection, the grounded conductor run with the supply to the building or structure shall be permitted to serve as the ground-fault return path if all of the following requirements continue to be met: (1) An equipment grounding conductor is not run with the supply to the building or structure. (2) There are no continuous metallic paths bonded to the grounding system in each building or structure involved. (3) Ground-fault protection of equipment has not been installed on the supply side of the feeder(s). If the grounded conductor is used for grounding in accordance with the provision of this exception, the size of the grounded conductor shall not be smaller than the larger of either of the following: (1) That required by 220.61 (calculation for neutral size) (2) That required by 250.122 (Table 250.122 Minimum Size Equipment Grounding Conductors for Grounding Raceway and Equipment)  250.32(C) refers to ungrounded systems ( not applicable here)


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## John Hasler (Mar 22, 2014)

They've changed it.  The very old version I have available makes it clear that a panel in an outbuilding was to be treated as the service entrance to that building (and grounding conductors were not to be run between buildings).  The new version is clear as mud.


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## jim18655 (Mar 22, 2014)

John Hasler said:


> They've changed it.  The very old version I have available makes it clear that a panel in an outbuilding was to be treated as the service entrance to that building (and grounding conductors were not to be run between buildings).  The new version is clear as mud.


  1999 and earlier versions allowed either way. If you didn't run a ground, such as an overhead tri-plex, it was considered a service  and service rules applied. If you ran a branch circuit then it was a sub-panel. We still don't know how his panel is fed and which connection would be correct.


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## rdean (Mar 22, 2014)

In 1975 and 76 I taught NEC at a vocational college along with motor relay control.  After nearly 40 years as an electrician working with NEC I have found it to be confusing and contradicting.   (maybe I am just getting old)  
Usually you end up doing what the electrical inspector requires for your location.

Good post jim18655

Ray


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## John Hasler (Mar 22, 2014)

rdean said:


> In 1975 and 76 I taught NEC at a vocational college along with motor relay control.  After nearly 40 years as an electrician working with NEC I have found it to be confusing and contradicting.   (maybe I am just getting old)
> Usually you end up doing what the electrical inspector requires for your location.
> 
> Good post jim18655
> ...



Nothing I do ever gets inspected (inspectors are thin on the ground in our rural jurisdiction) and I have confidence in my engineering judgement so I treat the code as a standard, not a law.  It's useful for that.  When I worked at Univ. of Mich. Hospital the code was an important reference but it often didn't apply.  When it comes to grounding I've always relied on the IEEE Green Book.


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## rdhem2 (Mar 23, 2014)

Mr. rdean says _Usually you end up doing what the electrical inspector requires for your location.

This is quite possibly the best answer I have seen through any of our efforts.  Many times I did things I did not understand at the time, could find no reference to and did not believe in, but completed the job in the manner I was told to get inspector's approval.  What I liked best was to get a different inspector at a later date who would completely disagree with the method of installation.  When I explained the circumstances to them and the source of information they no longer wanted to discuss the matter.  Right or wrong, real meaning to the term "Thick as thieves".
__
Russell Dean to rdean-- great point & quote!!!!!!!!!!_


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## Tony Wells (Mar 23, 2014)

Pretty much as I have always observed. NEC is a National Code.....fine, but whatever the locals require is what counts. As long as they are happy, your insurance company will be.


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## mkeller (Mar 23, 2014)

Thanks for all the help guys.  To answer a few questions, 
Yes i would call it a sub panel in my shed there is a  wire comming from my main panel in my house to feed it.
I got the 3 phase wiring changed around  and marked the white wire green. 
The grounding and bonding is getting a little over my head so i think i may just bring in a electrition to see what i have going on.
Ill let you know what i come up with
Mike


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## John Hasler (Mar 23, 2014)

mkeller said:


> I got the 3 phase wiring changed around  and marked the white wire green.
> Mike



That's the only color you *should not* use.  Change that to red or black or blue.  Green is reserved for the non-current-carrying safety grounding conductor.

Having an electrician look at the panel is a good idea.  He'll know what your local inspector requires.


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## rdhem2 (Mar 23, 2014)

Good discussion guys and a special thanks to Tony Wells for stealing "MY" usual line.  HA!  LOL!   :roflmao:


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## Dave Smith (Mar 23, 2014)

John Hasler said:


> That's the only color you *should not* use. Change that to red or black or blue. Green is reserved for the non-current-carrying safety grounding conductor.
> 
> Having an electrician look at the panel is a good idea. He'll know what your local inspector requires.




John and others--I'm not an electrician--but It sure looks like the big white wire is the neutral that is coming from the main panel with a black and a red and bare ground wire so I don't know why you would want to change the color or connect it to the bonded ground bar in a sub panel..I will be happy to know how this all comes out, and I pray no one gets hurt.---one thing to learn--if you don't understand electricity--then don't do wiring and definately do not throw the power to it untill it is inspected by the inspector------just my concerns-------Dave


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## John Hasler (Mar 23, 2014)

Dave Smith said:


> John and others--I'm not an electrician--but It sure looks like the big white wire is the neutral that is coming from the main panel with a black and a red and bare ground wire so I don't know why you would want to change the color or connect it to the bonded ground bar in a sub panel..I will be happy to know how this all comes out, and I pray no one gets hurt.---one thing to learn--if you don't understand electricity--then don't do wiring and definately do not throw the power to it untill it is inspected by the inspector------just my concerns-------Dave



I understood him to be saying that he had used a white wire for the "synthetic phase" going from his converter to his three-phase motor and then had painted it green.  The panel is another issue.  I think he should have an electrician look at that.  For one thing, we don't know how the feeder is hooked up at the other end.


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## mkeller (Apr 7, 2014)

All right;
Took a while but i got everting ironed out and the machine is running.  Had a electrion come in and things were mostly ok.    At the 3 phase panel i had the neutral tiheed in to the earth ground.  I also had the "manufactureed" leg of the 3 phase power comming into the wrong lug  at the machine panel.
Thanks for all the help.  I mentioned the replys here to the electrition and he said that its all different depending where in the state/world your are.
Got to get back to the shop and get parts running.
Thanks again.
Mike


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