Grounding & Bonding for DIFFERENT Reasons

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Grounding & Bonding for DIFFERENT Reasons

  • Yes this is useful information in my workplace

    Votes: 14 73.7%

  • No this is not useful information in my workplace

    Votes: 5 26.3%
  • Total voters
    19
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nakulak said:
"drain . . .circuit" is a term that in my opinion merely obfuscates and confuses.
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The High voltage and Data/communication/signal electricians use this ?drain circuit? terminology and mindset not me, this is the confusion I?m trying to point out.

nakulak said:
I think your information is well intentioned, and is a good start for a 1-page presentation (if that's what it is).
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No that is not what I intend to convey. I?m not even trying to teach but I am making an observation that over the years has proven to confuse electricians with different backgrounds. My intent is to point out that different types of electricians use and understand grounding and bonding differently causing confusion between others and us.

This is what I meant to say in [or by] my original post:

Even the label ?electrician? is too broad and not descriptive enough causing confusion regarding installations especially grounding and bonding. These different electrical trades DO ground commonly to control lightning and transformer failures but that?s it, they do NOT share common reasons for ground fault control (equipment ground conductors & effective ground fault path) or even unbalance load return path, the grounded conductor (neutral)?
In summary we really have 3 worlds colliding with electricians and their use of grounding:
1 High voltage = return path for the unbalanced load/drain to open circuit/effective ground fault path/lightning & transformer failure control
2 Data/communication/signal = drain to clean circuit/lightning & transformer failure control
3 Premises wiring of 600 volts and less = lightning & transformer failure control ONLY!

My hope is to untangle the broad use for reasons to ground while untangling the broad use of the label ?electrician?
 
Terms that obfuscate.

Terms that obfuscate.

nakulak said:
"drain . . .circuit" is a term that in my opinion merely obfuscates and confuses. Current returns to source. I think your information is well intentioned, and is a good start for a 1-page presentation (if that's what it is). Mike Holt's "Grounding and Bonding" is a great DVD, if you want to provide your workplace with some training, however, and I strongly recommend it (not because this is Mike's forum, but because I bought it and its very informative).
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Nakulak,

Source and drain is an early term used in electronics for basically the input and output of a tunnel diode FET.(Field Effect Transistor)
 
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Grounding subpanel

Grounding subpanel

Hello,

I am installing a 100 amp service to an adjacent building. I see that it is required to run an EGC between the two buildings if there is are conductive paths such as water lines, etc. between the two buildings. In this case I understand that the neutral is not bonded to the panel and EGC. Can I save money by not running an EGC between the two buildings and run the EGC directly to ground rod itself and not back to the main panel in the first building? I know I have to install a ground rod by code anyway.

Thanks
 
Ken 6789 said:
Hello,

I am installing a 100 amp service to an adjacent building. I see that it is required to run an EGC between the two buildings if there is are conductive paths such as water lines, etc. between the two buildings. In this case I understand that the neutral is not bonded to the panel and EGC. Can I save money by not running an EGC between the two buildings and run the EGC directly to ground rod itself and not back to the main panel in the first building? I know I have to install a ground rod by code anyway.

Thanks
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You do need an electrode at the separate building but you cannot use earth as your conductor. You have to install an EGC as per 250-118 & 250-122.
 
1113844523_6.jpg

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I believe the illustration above does explain why we ground to the earth.

If you would look again you will see that there is a build up of 2,200 volts on the secondary system.

This is not to say that the electrical loads hooked to this secondary system would not work.All they need is the 208 or 240 current voltage supplied by the magnetic flux from the primary and their supplied with what they need to run.


The Aurthur of this is seeing a large capacitor the whole secondary all 4 line conductors loads and secondary transformer windings as one capacitor plate and the other capacitor plate being the earth or in this case the metal conduit and metal enclosure as the other plate.


In other words although not on purpose, a large capacitor has been created.

If this system was grounded or electrically bonded to the earth and all the other conductive materials around this capacitor will not be created.

In this case the bonding takes place at the xo or neutral known as the grounded conductor.




Capacitance charging is still theory.But past experience and research has shown this voltage build up can and does take place such as the 2200 volts shown above.This 2,200 volts is a capacitance voltage between the secondary system and the earth.Not between the lines of the secondary they would read normal 208,240,277 etc.

The best way to avoid this is grounding or earthing the system.Doing this you are shorting the capacitor out or really eliminating it.

And if you don't ground eventually it will be high enough to break down the plastic insulation of the conductors and would sooner or later short the secondary out.


And this lets the smoke out of everything,, :D *** :D

This is what the term means when they say the earth ground keeps the system stable.
 
Ron, I am definitely confused.

How can there be 'real' potential between the 'hots' and earth of a system with no connections to earth?

That seems to break all rules of needing a complete circuit.
 
Hi Bob

That is the way I see the illustration.This is just my opinion and its open for discussion.

I now am an old timer. But back in my younger days when other older electricians where my age, that is what they preached to me would happen with a service with no ground to earth.

This was also in the electrical literature in electrical books.

In my work I have worked in Industrial,commercial and residential.You know yourself that all services have a earth ground of some kind.Solid ground,
spark gap or high resistance.


I know there are some special cases where somethings are not grounded to earth but they deal with this in a different way.

I have to be honest with you, as long as I have been in this trade I have never seen this first hand.But when I first got into the trade many,many years ago it was not unusual to use a megger.And the electricians I worked with would stress the point to make sure that I grounded the conductors to ground to bleed the charge on the wire off after putting a high voltage on them for test.

What else would the illustration be talking about other than a charged system acting like a capacitor.If the line that the arrow is pointing at has 2200 volt it wouldn't the other lines?

I will study it again I don't think they where talking about a high voltage transformer system, I just assumed it was a low voltage system like 480 to 208/120.

Any way thats my two cents.
 
Ron,

This may explain how a transformer can act like a capacitor, nicely explained at that! But the confusion about grounding between actual electricians are done for different reasons, it would be great if we can evolve to use different words for these different reasons rather than just ?ground?.

So with this transformer example a premises electrician is grounding for particular and specific reasons yet a data/comm. electrician wouldn?t think of these same reasons but certainly uses the ?grounding? terminology often. Also the premises electrician will ground at the service disconnect but the linemen may not even think of grounding at the service disconnect because he has ground at his transformer.
 
iwire said:
Ron, I am definitely confused.

How can there be 'real' potential between the 'hots' and earth of a system with no connections to earth?

That seems to break all rules of needing a complete circuit.
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Bob this is not a intented situation its just the way capacitance works.

The point of the illustration is that there is no bonding jumper to earth between the XO and earth.And that makes the system unstable. :)
 
I agree

A communication tech. will ground to keep his system noise down.

I think the illustration explains it good if you really study it and think about it like a condenser or capacitor.

You could use lightning as an example ,, its not a two wire circuit its just charged floating atmosphere or clouds with a charge that builds up and finally discharges to earth through closest thing it finds.
 
ronaldrc said:
...I believe the illustration above does explain why we ground to the earth. ......Capacitance charging is still theory.But past experience and research has shown this voltage build up can and does take place such as the 2200 volts shown above. ...
...The best way to avoid this is grounding or earthing the system. ...
...This is what the term means when they say the earth ground keeps the system stable.
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Ron -
Excellent illustration on re-striking, arcing ground faults. Also an excellent quote on earth grounding keeping the system stable.

I looked for your quote the the green book - couldn't find it. However I did find:
"Numerous advantages are attributed to grounded systems, including greater safety, freedom from excessive system overvoltages that can occur on ungrounded systems during arcing, resonant or near-resonant ground faults, and easier detection and location of ground faults when they do occur."
Which is pretty close to what you are advocating - grounding to prevent overvoltage from re-striking, arcing, ground faults.

I would consider this phenomena more than just theory. The research has been around for a while:


"Resonant effects can occur when the ground fault path includes an inductive reactance approximately equal to the system capacitive reactance to ground. Beeman [10], pp. 281-285, discusses this phenomenon in depth."​
([10] Beeman, D., Editor. Industrial Power Systems Handbook. New York: McGraw-Hill, 1955.)


However, rather than saying this why grounded systems are prefered, I would say this is one reason why ungrounded systems are not preferred.

Note: My understanding is this OV is not a problem is other than ungrounded 480.
1. 120/208, 120/240 systems are required to be grounded by NEC - which may not matter anyway, the voltage is pretty low.

2. In 240D systems the voltage is not high enough for the re-striking, arcing fault to occur.

3. Systems above 600V are generally resistance or reactance grounded.

4. Yes, plenty of exceptions exist

As you likely can tell, I am not a fan of solidly grounded 480V systems for industrial use. There are other systems that I believe to be more reliable and equally stable.

carl
 
Carl Thanks for your reply

Good to know there are some on here that understand what we are talking about.

You are right about the 480 systems, I guess thats why the NEC requires
anything over 1000 amps. at 480 to be GFI protected.

And like you are saying even with that sometime the things are so sensitive a 30 amp. arc will shut a 4000 amp.main breaker down and shut the whole plant or what ever off.

And that can be very costly production wise. :)
 
ronaldrc said:
...Good to know there are some on here that understand what we are talking about. ...
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Yes it is. I just wish I was one of them a little more often - especially about this subject. :)

carl
 
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I voted "no" because the information would not be useful 'in my workplace'.

that is to say, maybe 2 out of 50 electricians that i work with understand the difference of 'grounding' for lightning and overvoltage control, and BONDING for overcurrent devices which is what EVERYONE calls Grounding. (and fewer than maybe 15 even CARE)

However, I did find the information Very useful and applicable in my own understanding.
 
izak said:
I voted "no" because the information would not be useful 'in my workplace'.

that is to say, maybe 2 out of 50 electricians that i work with understand the difference of 'grounding' for lightning and overvoltage control, and BONDING for overcurrent devices which is what EVERYONE calls Grounding. (and fewer than maybe 15 even CARE)

However, I did find the information Very useful and applicable in my own understanding.
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I am with you alot of the people I know dont care about this issue and feel it is way to much worry..But now we are back to some interesting terms again..when grounding for overvoltage control (stabilization) does that not consitute a purposeful use of a ground and make that a functional ground? while grounding for lightening protection make the grounding a protectional ground? I know terms that are not liked and a function prohibited by the NEC..
 
izak said:
I voted "no" because the information would not be useful 'in my workplace'.

that is to say, maybe 2 out of 50 electricians that i work with understand the difference of 'grounding' for lightning and overvoltage control, and BONDING for overcurrent devices which is what EVERYONE calls Grounding. (and fewer than maybe 15 even CARE)

However, I did find the information Very useful and applicable in my own understanding.
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Kinda like saying ?neutral? our whole crew knows what it is regardless of phasing. Then say grounded conductor in the same group and lose a few or at least distract em.
 
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