# Ungrounded systems are safer



## dielectricunion

My coworker was telling me that his teacher in trade school had once told them that he thought old ungrounded systems were actually safer than the modern grounded system.

His school days were a long while back and he couldn't remember much else about that teachers statements.

Anyone have any idea what this might pertain to? Kind of a random stab in the dark but it got me curious.


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## papaotis

apparently he was never shocked enough:whistling2:


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## ponyboy

Ungrounded systems are better for some industrial settings since they provide a continuity of service that grounded systems don't. More or less you get a free ground fault condition in an ungrounded service but you must have ground fault indication systems in place to alert of the fault. When a fault is observed proper procedures can be taken to correct the fault in a safe and timely manner. If a second fault occurs then there's much bigger problems since you're phase to phase now. Ungrounded systems have their place but it takes qualified people to maintain them


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## JW Splicer

Some industrial facilities and utilities use them for reliability, not safety. Comes back to the almighty dollar. But that is also starting to change, most installs now are grounded systems for safety, and protection of equipment.


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## chicken steve

dielectricunion said:


> My coworker was telling me that his teacher in trade school had once told them that he thought old ungrounded systems were actually safer than the modern grounded system.
> 
> His school days were a long while back and he couldn't remember much else about that teachers statements.
> 
> Anyone have any idea what this might pertain to? Kind of a random stab in the dark but it got me curious.


Pertaining to interior wiring methods, the introduction of a 3rd bare grounding conductor was originally viewed as a potential uninsulated_ lethal_ path by the trades then pundits.

There are still 1/2 century old installs ticking along where improper , or no terminations of said conductor can be seen. It's like they had _no clue_ what do do with it:no:

As pertains to an incoming service , a comparative analysis of TT, TN and IT systems characteristics would be apropos 

~CS~


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## macmikeman

First - get the definition of ungrounded system correct. Doesn't mean you don't bond all metal equipment in the system together and do a single join to the neutral return path at the first disconnect. It means no earth connection. I sit on the fence about this one, and personally consider that IF I was the former chairman of Oracle and owned the entire island of Lanai, I would have made that place a testing ground for undgrounded wiring, so we could settle this chit once and for all. ''Stabilizes the voltage to ground during a fault'' my ass.


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## Zog

JW Splicer said:


> Some industrial facilities and utilities use them for reliability, not safety. Comes back to the almighty dollar. But that is also starting to change, most installs now are grounded systems for safety, and protection of equipment.


Right, what is being used now where ungrounded systems used to be used are HRG systems, best of both worlds.


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## chicken steve

macmikeman said:


> IF I was the former chairman of Oracle and owned the entire island of Lanai, I would have made that place a testing ground for undgrounded wiring, so we could settle this chit once and for all. ''Stabilizes the voltage to ground during a fault'' my ass.


I wish it for you Mac :thumbup:

I'd also wager enough _earthing_ of noodles on Lanai would result in a reduced population of ocean life in the channel over to Molokai.....:whistling2:~CS~:laughing:


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## LGLS

macmikeman said:


> First - get the definition of ungrounded system correct. Doesn't mean you don't bond all metal equipment in the system together and do a single join to the neutral return path at the first disconnect. It means no earth connection. I sit on the fence about this one, and personally consider that IF I was the former chairman of Oracle and owned the entire island of Lanai, I would have made that place a testing ground for undgrounded wiring, so we could settle this chit once and for all. ''Stabilizes the voltage to ground during a fault'' my ass.


Won't work. The data b!tches installing your LAN cabinet will *still* demand an isolated ground.


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## dmxtothemax

dielectricunion said:


> My coworker was telling me that his teacher in trade school had once told them that he thought old ungrounded systems were actually safer than the modern grounded system.
> 
> His school days were a long while back and he couldn't remember much else about that teachers statements.
> 
> Anyone have any idea what this might pertain to? Kind of a random stab in the dark but it got me curious.


A wide open subject !
You need to be more specific
There are some situations where un grounded systems can be beneficial
But on the other side there are situations where grounding IS beneficial


grounding is a very complex subject with many aspects to it
So please be a bit more specific ?


So let the arguments begin !

:whistling2:


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## macmikeman

IslandGuy said:


> Won't work. The data b!tches installing your LAN cabinet will *still* demand an isolated ground.


Damn, you are right. I hadn't thought about that........:thumbsup:


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## 51360

dielectricunion said:


> My coworker was telling me that his teacher in trade school had once told them that *he thought old ungrounded systems were actually safer than the modern grounded system.*
> 
> *His school days were a long while back *and he couldn't remember much else about that teachers statements.
> 
> Anyone have any idea what this might pertain to? Kind of a random stab in the dark but it got me curious.


I agree that the original poster should have been more specific, ( seems to be happening a lot lately ). 

When I first read this thread, I thought the teacher was referring to branch circuits in homes without a ground, ( bond ), wire.  As did others, I think that's what chicken was getting at. 

Now I am just tired! :laughing:

Borgi


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## fdew

Some early electric codes prohibited grounding. Some even required a couple of lights wired between each incoming conductor and earth ground so the building owner would be alerted if the system became grounded


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## dielectricunion

I was under the impression that the teacher was saying that old systems that did not use an EGC were safer, and that's how my coworker had taken it.

It makes much more sense that he was talking about a system that didn't use a connection to earth and GEC.

It was an incredibly vague post, sorry about that


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## varmit

All types of power distribution have their uses IF SELECTED AND MAINTAINED PROPERLY. 

Ungrounded systems are mostly to allow service to continue on an initial ground fault. Of course if multiple phases are shorted, you have a phase to phase fault that can have a very high fault current, possibly damaging equipment. One negative safety consideration of ungrounded systems is the possibility of improperly bonded equipment becoming energized and a potential shock hazard between other equipment with a different potential to ground.

Nothing in life is perfect.


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## cabletie

The only time I came across an ungrounded system was on a navy training ship. As already mentioned it was safer to have ground fault indicators, rather than having a grounded system. This would allow operation of the faulted equipment until it could be repaired or the fault got worse. In some cases it is imperative that the equipment continues to work, in the worst conditions, with a single fault.


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## excelblue

Grounded systems get their safety from the fact that breakers trip during a ground fault. If you can rely on your breakers, then everything's good. However, if the breakers don't trip fast and reliably, there's an energized ground and an electrical fire.

The tradeoff is: when can you rely on the circuit breakers more than you can rely on a fault not occurring in the first place? That's what's changed: breakers are critical safety equipment.


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## macmikeman

excelblue said:


> Grounded systems get their safety from the fact that breakers trip during a ground fault. If you can rely on your breakers, then everything's good. However, if the breakers don't trip fast and reliably, there's an energized ground and an electrical fire.
> 
> The tradeoff is: when can you rely on the circuit breakers more than you can rely on a fault not occurring in the first place? That's what's changed: breakers are critical safety equipment.


Let's go back to whAt I said earlier, an ungrounded system does not mean there is a lack of equipment bonding. Both systems need equipment bonding.


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## 51360

macmikeman said:


> Let's go back to whAt I said earlier, an ungrounded system does not mean *there is a lack of equipment bonding. * Both systems need equipment bonding.


Agreed! Not sure about the NEC but, the CEC distinguishes the two, ( grounding and bonding ), at the main source of supply. 

Borgi


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## JRaef

Ungrounded / HRG systems are the #2 killer of VFDs (after excessive heat) and other power electronics systems. So although the reliability factor was true back in the day, it no longer is, unless you have a facility with NO power electronics equipment. That would be very rare now. Sure, there are steps you can take to protect your power electronics, but few people do because it co$t$. They just gripe about how unreliable power electronics are.


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## Vintage Sounds

JRaef said:


> Ungrounded / HRG systems are the #2 killer of VFDs (after excessive heat) and other power electronics systems. So although the reliability factor was true back in the day, it no longer is, unless you have a facility with NO power electronics equipment. That would be very rare now. Sure, there are steps you can take to protect your power electronics, but few people do because it co$t$. They just gripe about how unreliable power electronics are.


If I may ask, what is it about these systems that kills VFDs?


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## Jerome208

JRaef said:


> Ungrounded / HRG systems are the #2 killer of VFDs (after excessive heat) and other power electronics systems. So although the reliability factor was true back in the day, it no longer is, unless you have a facility with NO power electronics equipment. That would be very rare now. Sure, there are steps you can take to protect your power electronics, but few people do because it co$t$. They just gripe about how unreliable power electronics are.


I am intrigued, please expand....


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## AMP_Electric

Jerome208 said:


> I am intrigued, please expand....


I believe what he's talking about is the propensity of HRG systems to pop components on the control circuitry and the like. This is usually due to installation issues though (not converting it to unfiltered by pulling the Y cap, no output choke, not rated as use on an HRG, etc...) that are usually found in a short time, hence the blaming it on the HRG.


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## telsa

EUSERC moved against ungrounded Services (1945) only after discovering the huge downside: *failing* transformers ( and autoformers ) can back feed astounding voltages -- transients -- up into the Poco grid.

If such customer equipment never misbehaved, then ungrounded Services wouldn't be problematic for the Poco.

BONDED systems save people... by establishing an equipotential voltage.

Bonded and grounded systems protect against lightning -- _by not attracting the jolts in the first place._ 

This principle is best illustrated with van de Graaff generator design, famed for astounding voltages. The charge is invariably collected by a sphere or something like it -- with an extremely even, smooth conducting surface. Such a ball is a model for the entire planet Earth. It also is able to attain astounding voltage -- relative to the upper atmosphere. 

The whole point of bonding and grounding a structure is to place it at the SAME potential as the surrounding ground... very much like smoothing the ball of the van de Graaff machine. 

If a lightning bolt were to hit a home -- it is going to be trashed. No home is ever wired to pass the energy of a lightning bolt.

To see what it takes -- note the rocket pads in Florida. They have four huge towers -- taller than the rockets -- to shunt lightning bolts. 

Ben Franklin's old lightning protection system -- unwittingly -- worked on the basis that he was bonding the whole structure to local ground potential. Like magic, lightning bolts were no longer attracted to the church steeple. 

{ In the 18th Century, church steeples [ tallest thing in town ] were getting zapped all over Europe. Naturally, such zaps were taken as a sign from God. Heh. }


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## macmikeman

telsa said:


> EUSERC moved against ungrounded Services (1945) only after discovering the huge downside: *failing* transformers ( and autoformers ) can back feed astounding voltages -- transients -- up into the Poco grid.
> 
> If such customer equipment never misbehaved, then ungrounded Services wouldn't be problematic for the Poco.
> 
> BONDED systems save people... by establishing an equipotential voltage.
> 
> Bonded and grounded systems protect against lightning -- _by not attracting the jolts in the first place._
> 
> This principle is best illustrated with van de Graaff generator design, famed for astounding voltages. The charge is invariably collected by a sphere or something like it -- with an extremely even, smooth conducting surface. Such a ball is a model for the entire planet Earth. It also is able to attain astounding voltage -- relative to the upper atmosphere.
> 
> The whole point of bonding and grounding a structure is to place it at the SAME potential as the surrounding ground... very much like smoothing the ball of the van de Graaff machine.
> 
> If a lightning bolt were to hit a home -- it is going to be trashed. No home is ever wired to pass the energy of a lightning bolt.
> 
> To see what it takes -- note the rocket pads in Florida. They have four huge towers -- taller than the rockets -- to shunt lightning bolts.
> 
> Ben Franklin's old lightning protection system -- unwittingly -- worked on the basis that he was bonding the whole structure to local ground potential. Like magic, lightning bolts were no longer attracted to the church steeple.
> 
> { In the 18th Century, church steeples [ tallest thing in town ] were getting zapped all over Europe. Naturally, such zaps were taken as a sign from God. Heh. }




'' after discovering the huge downside: *failing* transformers ( and autoformers ) can back feed astounding voltages -- transients -- up into the Poco grid." :roll eyes:


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## MTW

Vintage Sounds said:


> If I may ask, what is it about these systems that kills VFDs?


Offhand, I would guess that high capacitance found in ungrounded systems is what kills VFD's.


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## CharlieCarcinogen

I know a lot about this stuff so if you need to know anything just ask.


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## CharlieCarcinogen

macmikeman said:


> '' after discovering the huge downside: *failing* transformers ( and autoformers ) can back feed astounding voltages -- transients -- up into the Poco grid." :roll eyes:


My supply house has those for $20. So I go to Home Depot to pick them up for $11. But the contractor pack with same transformer also comes with a push button and chime for... $11.

They cray cray.


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## macmikeman

CharlieCarcinogen said:


> My supply house has those for $20. So I go to Home Depot to pick them up for $11. But the contractor pack with same transformer also comes with a push button and chime for... $11.
> 
> They cray cray.


Same deal over here. But from now on I won't be putting any in because I don't want to send crazy high voltage transients back to the poco when they start failing.


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## telsa

Wall warts and such.... Heh.

BTW, until they 'scoped' it out... no-one suspected nothing.

Back in 1944 everyone held your opinion...

Then they got kicked in the a$$ [ with fatalities ] and founded EUSERC.

It's PRIMARY original target was ungrounded systems -- industrial accounts, of course.

Doorbell transformers... that's a good one... and L-N loads at that. Heh.


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## CharlieCarcinogen

macmikeman said:


> Same deal over here. But from now on I won't be putting any in because I don't want to send crazy high voltage transients back to the poco when they start failing.


Jobs and lives man, jobs and lives.


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## macmikeman

telsa said:


> Wall warts and such.... Heh.


Same laws of physics apply to all ac transformers. But in my experience, those ungrounded transformers do not set the world on fire when they start failing.


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## CharlieCarcinogen

Telsa, can you explain to me the point of the neutral? I would like to know what it does, but no one seems to know.


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## telsa

macmikeman said:


> Same laws of physics apply to all ac transformers. But in my experience, those ungrounded transformers do not set the world on fire when they start failing.


Failing transformers in an ungrounded environment end up producing goofy transforms -- in effect creating their own taps.

While they [ cooked transformers] killed some Southern California Edison employees ( IBEW ) until the EEs pulled everything apart -- using power quality tests -- nothing was making any sense.

No-one could mentally imagine what was going on.

IIRC, the focus of this effort was a war-critical defense plant. It was on an ungrounded Service precisely because the War Department didn't want unscheduled downtime.

AFTER the 'scopes showed that peak voltages were off the charts -- the EEs backed into what had happened. They even tracked the faulting circuits down to the specific transformers/ autoformers.

It was after all of this -- that teams of EEs sat down and resolved: ungrounded Services are vulnerable to weird voltages -- when transformers fail -- and internally rewire themselves to craft wholly new transforms. 

( The turns ratio jumps all over the lot. The most common mode of failure is a puddled, smoking, stinking transformer. That's no problem at all, not a threat. 

What no-one expected was that flawed transformers with strange connections were able to weirdly replicate the discharges typical in an automobile coil. 

Modern electronics has changed the automobile. Up until the electronic era, spark plugs were fired by a pulse from a 'coil' -- aka a transformer that sucked in 12 VDC ( actually only 6 VDC -- but that's another story ) and boosted that to 25,000 VDC -- PULSED -- to fire the spark plug. ( it had only the one polarity and is THE classic example of impedance in DC circuits. The intense voltage increase is due to the fact that it's an *UN*-grounded circuit. The collapsing magnetic field will take the EMF to astonishing voltages -- until it's discharged. 

The energy is not so great, the voltage is sky high. )

In the actual case history, the faulting system was cranking out well over 2,000 peak volts where 208 was expected... shooting right back up the line. Fatalities and casualties occurred.

This whole travail was written up EXTENSIVELY ages ago. I wish I still had the link.

All of the Poco EEs in greater LA sat down and concluded that ungrounded Services have risks previously never conceived. In fact, the only time to provide such a Service is when other safety factors kick in. ( paper mills, etc. ) 

PG&E and Southern California Edison founded EUSERC (1945) to address this issue and all of the sloppy Services that had been thrown together during the WWII super-boom.

Don't take aim at me. Take aim at EUSERC and all of its EEs and Pocos. 

Have fun. Do correct them. They are _waiting_ for your critique. :thumbsup:

BTW, you'll find that even non-EUSERC Pocos are now reluctant to initiate ungrounded Services. Out here, they require a special pleading.

EUSERC Pocos just LOVE the uniformity of Service designs -- and the extra wire room that's in them.

EUSERC standards effectively eliminate EC 'value engineering' of Services. The Poco is NOT interested in how clever you might be in value engineering. They HATE screw-ball set-ups.

The photos of eastern Services freak us western (EUSERC) boys out.


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## telsa

CharlieCarcinogen said:


> Telsa, can you explain to me the point of the neutral? I would like to know what it does, but no one seems to know.


Transformer circuits are ultimately so complicated that they are a sub-specialty even for EEs.

The very term "neutral" is consequent to the Wye wound transformer/ three phase alternator.

It stands 'neutral' [ ie even ] to all of the three hot phases.

The term migrated to the mid-point tap of 240//120 residential Services. 

Obviously, a center tap is equally between both hots, and is 'even' to all two legs of power.

The reason Wye -- grounded Wye -- distribution is so popular is that it uses the Earth as a titanic 'snubber' // absorber // buffer of electro potential. It's the perfect target to dump weird transients/ voltages/ energies.

Since I'm constantly critiqued for over-long posts --

You are going to have to tackle physics texts and EE handbooks.

1) We ALL think in idealized terms. We are instructed in idealized electric laws.

2) We are ALL instructed that A/C power has impedance, DC power has resistance. 

But that is FALSE.

Without DC impedance, our computers would not run. Indeed, most of modernity is built upon DC impedance.

3) DC impedance is TIME dependent. It's gone in a blink. That's why -- all through the 19th Century -- even the brightest minds did not know that DC had impedance. All that they could ever measure was resistance. Transient states were too brief to witness.

Such idealization is why Mike is struggling to imagine seriously fouled up transformers. The human mind can't imagine all of the weird voltages that messed up transformers can kick back up into the system. 

Healthy transformers == no problem.

Bizarre shut-down jolts -- wow I never thought that turning the dang thing OFF would kick back that extreme voltage from a collapsing magnetic field.

6 VDC ==> 25,000 VDC pulsed -- you say.... 

Yep, 

None of this weirdness occurs in GROUNDED systems. 

Which is what most all of us deal with. 

Very, very, few electricians ever face this screw-ball situation. They don't know what they're missing !


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## CharlieCarcinogen

That's wrong, it's all wrong. The neutral takes the power back so electrical things work.


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## telsa

CharlieCarcinogen said:


> That's wrong, it's all wrong. The neutral takes the power back so electrical things work.


Heh. :laughing:


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## RIVETER

JW Splicer said:


> Some industrial facilities and utilities use them for reliability, not safety. Comes back to the almighty dollar. But that is also starting to change, most installs now are grounded systems for safety, and protection of equipment.


An ungrounded system is safe these days. It is important to know that even in "ungrounded" systems all of the electrical system metal enclosures still have to be bonded at the service. An UNGROUNDED electrical system is simply an electrical system that a PHASE conductor is not INTENTIONALLY grounded. Now it may be time for more questions.


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## MTW

telsa said:


> Failing transformers in an ungrounded environment end up producing goofy transforms -- in effect creating their own taps.
> 
> While they [ cooked transformers] killed some Southern California Edison employees ( IBEW ) until the EEs pulled everything apart -- using power quality tests -- nothing was making any sense.
> 
> No-one could mentally imagine what was going on.
> 
> IIRC, the focus of this effort was a war-critical defense plant. It was on an ungrounded Service precisely because the War Department didn't want unscheduled downtime.
> 
> AFTER the 'scopes showed that peak voltages were off the charts -- the EEs backed into what had happened. They even tracked the faulting circuits down to the specific transformers/ autoformers.
> 
> It was after all of this -- that teams of EEs sat down and resolved: ungrounded Services are vulnerable to weird voltages -- when transformers fail -- and internally rewire themselves to craft wholly new transforms.
> 
> ( The turns ratio jumps all over the lot. The most common mode of failure is a puddled, smoking, stinking transformer. That's no problem at all, not a threat.
> 
> What no-one expected was that flawed transformers with strange connections were able to weirdly replicate the discharges typical in an automobile coil.
> 
> Modern electronics has changed the automobile. Up until the electronic era, spark plugs were fired by a pulse from a 'coil' -- aka a transformer that sucked in 12 VDC ( actually only 6 VDC -- but that's another story ) and boosted that to 25,000 VDC -- PULSED -- to fire the spark plug. ( it had only the one polarity and is THE classic example of impedance in DC circuits. The intense voltage increase is due to the fact that it's an *UN*-grounded circuit. The collapsing magnetic field will take the EMF to astonishing voltages -- until it's discharged.
> 
> The energy is not so great, the voltage is sky high. )
> 
> In the actual case history, the faulting system was cranking out well over 2,000 peak volts where 208 was expected... shooting right back up the line. Fatalities and casualties occurred.


Yeah, that sounds completely plausible. :no::no:


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## Meadow

telsa said:


> The reason Wye -- grounded Wye -- distribution is so popular is that it uses the Earth as a titanic 'snubber' // absorber // buffer of electro potential. It's the perfect target to dump weird transients/ voltages/ energies.


No, simply no, its because it lets you use single bushing cans and reduced insulation on the HV windings. 

Most distribution systems around the world are 3 wire, half ungrounded, and nothing needs dumping of transients. 

Most older systems in the US before the 50s were ungrounded.

As for POCO transformers wye-wye is most common only when stepping 12kv to 208 or 480. When stepping 138kv to 12kv Delta wye is the most common. Delta wye is also the most common for GSUs. In some cases POCOs may alternate between a grounded transmission system, ungrounded sub-transmission and then grounded distribution. 









> Since I'm constantly critiqued for over-long posts --


Its not the length, but mountains of false information everyone knows to be untrue. 






> You are going to have to tackle physics texts and EE handbooks.
> 
> 1) We ALL think in idealized terms. We are instructed in idealized electric laws.
> 
> 2) We are ALL instructed that A/C power has impedance, DC power has resistance.
> 
> But that is FALSE.


Ive tackled many EE books, and they all contradict what you say. 







> Without DC impedance, our computers would not run. Indeed, most of modernity is built upon DC impedance.
> 
> 3) DC impedance is TIME dependent. It's gone in a blink. That's why -- all through the 19th Century -- even the brightest minds did not know that DC had impedance. All that they could ever measure was resistance. Transient states were too brief to witness.


Resistance is a form of impedance. So what you are then saying is DC did not even have resistance. 



> Such idealization is why Mike is struggling to imagine seriously fouled up transformers. The human mind can't imagine all of the weird voltages that messed up transformers can kick back up into the system.


True, even if solidly grounded. 





> Healthy transformers == no problem.
> 
> Bizarre shut-down jolts -- wow I never thought that turning the dang thing OFF would kick back that extreme voltage from a collapsing magnetic field.


Unlikely. In any cases grounded or ungrounded the earth isnt going to stop it. 





> 6 VDC ==> 25,000 VDC pulsed -- you say....
> 
> Yep,
> 
> None of this weirdness occurs in GROUNDED systems.


So your saying if I took an HID fixture and applied it to a grounded system the ignitor wont work? :laughing:




> Which is what most all of us deal with.
> 
> Very, very, few electricians ever face this screw-ball situation. They don't know what they're missing !


Plenty of electricians deal with both grounded and ungrounded systems.


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## Meadow

telsa said:


> EUSERC moved against ungrounded Services (1945) only after discovering the huge downside: *failing* transformers ( and autoformers ) can back feed astounding voltages -- transients -- up into the Poco grid.


A failing transformer is going to dump high voltage into the low voltage service if anything, not the other way around. Also, I have never heard of an auto transformer being used in a step down bank feeding a 600 volt and under customer. 



> If such customer equipment never misbehaved, then ungrounded Services wouldn't be problematic for the Poco.


Customer equipment has nothing to do with it. POCOs left delta secondaries because they wanted wye primaries. A wye primary with a delta secondary will pass zero sequence currents during primary faults which can blow cutouts on the banks. The solution was wye secondaries which most customers took anyway. 





> BONDED systems save people... by establishing an equipotential voltage.


Of course, grounding the neutral to that is relevant. Thats why article 250 requires ungrounded systems to have an EGC. 





> Bonded and grounded systems protect against lightning -- _by not attracting the jolts in the first place._


 

Do you have any links to back this up?




> This principle is best illustrated with van de Graaff generator design, famed for astounding voltages. The charge is invariably collected by a sphere or something like it -- with an extremely even, smooth conducting surface. Such a ball is a model for the entire planet Earth. It also is able to attain astounding voltage -- relative to the upper atmosphere.



Static charge vs AC power used to describe bonding  








> The whole point of bonding and grounding a structure is to place it at the SAME potential as the surrounding ground... very much like smoothing the ball of the van de Graaff machine.



The structure will not get the soil to equal potential. Everything inside might, but anything else (like a water spigot) will still have potential to earth soil. Grounding is not equal potential. 


In so far your vandy graph analogy leads me to believe that your idea of grounding and bonding is having the earth provide zero potential by soaking up electricity, not the case. 








> If a lightning bolt were to hit a home -- it is going to be trashed. No home is ever wired to pass the energy of a lightning bolt.
> 
> To see what it takes -- note the rocket pads in Florida. They have four huge towers -- taller than the rockets -- to shunt lightning bolts.
> 
> Ben Franklin's old lightning protection system -- unwittingly -- worked on the basis that he was bonding the whole structure to local ground potential. Like magic, lightning bolts were no longer attracted to the church steeple.
> 
> { In the 18th Century, church steeples [ tallest thing in town ] were getting zapped all over Europe. Naturally, such zaps were taken as a sign from God. Heh. }


We were on AC power and grounded vs ungrounded, how did we get to lightening protection? :blink:


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## Meadow

telsa said:


> Wall warts and such.... Heh.
> 
> BTW, until they 'scoped' it out... no-one suspected nothing.
> 
> Back in 1944 everyone held your opinion...
> 
> Then they got kicked in the a$$ [ with fatalities ] and founded EUSERC.
> 
> It's PRIMARY original target was ungrounded systems -- industrial accounts, of course.
> 
> Doorbell transformers... that's a good one... and L-N loads at that. Heh.



What are you trying to say? Im confused? :blink:


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## telsa

Get on the horn IMMEDIATELY.

EUSERC needs to hear your pitch.

You've proved thousands of EEs wrong -- and 70 years of PoCo studies.

We have a genius on our hands.


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## telsa

You WERE the same fella that diss'd the notion that a European complex machine just MIGHT be bonded neutral to chassis -- so check it out.

Yeah, it's on the record here.

You were TOTALLY wrong on that one, too.

The IEC manufacturer didn't meet your expectations -- so your feelings were hurt -- AFTER having diss'd me.

At least your vanity is consistent.

Just stop.

Stop embarrassing yourself.

You don't have the maturity, education or the temperament to be the opinion lord hereabouts.

The stuff you're not aware of does, indeed, fill libraries.

I remember stuff, I don't ever need to make stuff up out of whole cloth.

Stop opining -- and start googling -- ...


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## macmikeman

We still haven't answered what happens when the doorbell xfmr breaks down, to the wiring of the system or anything about the million volts of surge that doesn't happen. How do I know this? Well...... I have been a homeowner for bout thirty years. Lots of em. Seen my share of burnt out doorbell xfmr's and no explosions back at the power plant. I'm not trying to be rude, just practical. No big back surges of dc component either. The doorbell transformers don't have a built in fuse like wall warts do. When they fail it is always windings on coils that give out. By your reasoning, there should be at least ten thousand volts on the primary side of the circuit, which would melt the romex feeding the device, and trip a plug in breaker as well. Dudn't happen. Nope. Not today Junior, google or no google....


----------



## Meadow

telsa said:


> Get on the horn IMMEDIATELY.
> 
> EUSERC needs to hear your pitch.
> 
> You've proved thousands of EEs wrong -- and 70 years of PoCo studies.
> 
> We have a genius on our hands.



Millions of ungrounded systems still exist, you tell me whats up with that.


----------



## Meadow

telsa said:


> You WERE the same fella that diss'd the notion that a European complex machine just MIGHT be bonded neutral to chassis -- so check it out.



Yahhh, I nixed that one because I knew already what "PE" meant, and that fact TN-C is not allowed for conductors under 10mm2 which I doubt that machine took. Here it is again:

http://www.electrical-installation.org/enwiki/Definition_of_standardised_earthing_schemes


Rather then try to see where I was coming from and read the links which clearly would have been of help you just took it at face value and left. 








> Yeah, it's on the record here.


That you are incorrect. Wave physics does not explain an open neutral. 



> You were TOTALLY wrong on that one, too.


Show me. 



> The IEC manufacturer didn't meet your expectations -- so your feelings were hurt -- AFTER having diss'd me.


Thats how it looks to you when I knew the rules ahead of time. 





> At least your vanity is consistent.
> 
> Just stop.
> 
> Stop embarrassing yourself.


Yahhh, ok 






> You don't have the maturity, education or the temperament to be the opinion lord hereabouts.
> 
> The stuff you're not aware of does, indeed, fill libraries.
> 
> I remember stuff, I don't ever need to make stuff up out of whole cloth.
> 
> Stop opining -- and start googling -- ...



I think the saying that applies to might be 'their are none so deaf as those who refuse to see, none so blind as those who refuse to hear'

Rather then saying everyone is always wrong, why dont you try to show us why we are wrong.


----------



## telsa

meadow said:


> I think the saying that applies to might be 'their are none so deaf as those who refuse to see, none so blind as those who refuse to hear'
> 
> [ Preach it brother. ]
> 
> Rather then saying everyone is always wrong, why dont you try to show us why we are wrong.


At my rate of pay...

Nope.

I've actually shown fools their errors -- in person -- and when they FINALLY figure it out -- they are NOT happy campers -- let me tell you.

This forum needs more arrogance; yes, you are a blessing.

%%%

For the general readership:

*Circuit elements that can handle 392 VAC PEAK voltages all day long -- for decades -- ie a 277 VAC RMS system -- suddenly experience excessive voltages when their neutral is cut.*

Yet, absent wave physics, there is absolutely no voltage source available beyond that which existed before -- still the same old 392 VAC PEAK voltage. (consequent to the A/C sine wave form) All that has changed is that the draining conductor is now missing, aka, the neutral.

_Over voltages_ that burn out electronic ballasts ( from open neutrals ) can't be 
explained without wave physics. :no:

The neutral was never placed in contact with another hot phase -- to lift the voltage to 480 VAC RMS. (up from 277VAC) :no:

_With wave physics, the over voltages are simple Simon... as in straight out of the textbook -- as in all of them. Sheesh._ :thumbsup:

Brainiac here, STILL can't figure out that wave physics is the source of ALL of the harmonics that are discussed -- endlessly -- whenever high tech power manipulations are effected by solid state circuits. :blink:

It takes a particular density between the ears to dance around a fact that EVERYBODY else can dope out via Google, via an upper division physics text, or chatting it up with a graduate student in physics. :thumbsup: Chatter and laughter must be the result.

%%%

As for the rest of the riposte -- it's off at some remove from the facts advanced. As an attorney would put it: it's non-responsive. Political-speak, even.

{ You ask a politician about Mars -- and he jumps to Venus, the planet he really wants to talk about. }


----------



## Meadow

telsa said:


> At my rate of pay...
> 
> Nope.
> 
> I've actually shown fools their errors -- in person -- and when they FINALLY figure it out -- they are NOT happy campers -- let me tell you.
> 
> This forum needs more arrogance; yes, you are a blessing.


I sense some projection. :whistling2:



> For the general readership:
> 
> *Circuit elements that can handle 392 VAC PEAK voltages all day long -- for decades -- ie a 277 VAC RMS system -- suddenly experience excessive voltages when their neutral is cut.*
> 
> Yet, absent wave physics, there is absolutely no voltage source available beyond that which existed before -- still the same old 392 VAC PEAK voltage. (consequent to the A/C sine wave form) All that has changed is that the draining conductor is now missing, aka, the neutral.


Ummm, yahhh. The peak voltage of 277 is 392, you said that already. 

Of course circuit elements can handle peak voltage all day long, or the equivalent DC RMS from a dielectric stand point. 

However a magnetic circuit does not rely on peak alone, it relies on RMS as well. When the RMS voltage rises the core is driven into saturation, which means their is not enough counter EMF on the windings resulting in more winding current and thus substantially more I2R heating. 

The laws of induction come into play here. 






> _Over voltages_ that burn out electronic ballasts ( from open neutrals ) can't be
> explained without wave physics. :no:


Please define wave physics, you are using that term incorrectly. 






> The neutral was never placed in contact with another hot phase -- to lift the voltage to 480 VAC RMS. (up from 277VAC) :no:


Of course, under an open neutral the loads simply become in series. 

_






With wave physics, the over voltages are simple Simon... as in straight out of the textbook -- as in all of them. Sheesh. :thumbsup:

Click to expand...

_No, its not "wave physics", rather the impedance of the loads now in series is un-equal. One encounters an over voltage the other under voltage. 

The correct terms would be ohms law, kirchhoff's voltage law and thevenin's theorem for beginners. All 3 have nothing to do with wave physics. 






> Brainiac here, STILL can't figure out that wave physics is the source of ALL of the harmonics that are discussed -- endlessly -- whenever high tech power manipulations are effected by solid state circuits. :blink:


Harmonics have nothing to do with loads in series or the voltage drops associated across an impedance. 






> It takes a particular density between the ears to dance around a fact that EVERYBODY else can dope out via Google, via an upper division physics text, or chatting it up with a graduate student in physics. :thumbsup: Chatter and laughter must be the result.


At this point you are just beginning to sound like a bully. You can 
explain yourself without dragging the other person down. 




> %%%
> 
> As for the rest of the riposte -- it's off at some remove from the facts advanced. As an attorney would put it: it's non-responsive. Political-speak, even.
> 
> { You ask a politician about Mars -- and he jumps to Venus, the planet he really wants to talk about. }


As you do! :laughing:


----------



## Almost always lurkin

I politely request links. My google-fu is above average but I haven't found relevant material yet with a range of searches like "transformer backfeed transient" and others. And yes, I understand what -L dI/dt means.


----------



## chicken steve

telsa said:


> The collapsing magnetic field will take the EMF to astonishing voltages -- until it's discharged.
> 
> .


Decaying Magnetic Flux............can't even google it....~CS~


----------



## telsa

chicken steve said:


> Decaying Magnetic Flux............can't even google it....~CS~


https://www.google.com/search?q=aut...oTCIXqqbfKp8cCFUc6iAodUCkPBg&biw=1245&bih=835

Diagrams include modern and classic circuits.

Squib explanations of the circuit, too.

The collapsing magnetic field of an automotive coil forces a pulse of EMF out at extreme voltage ( tiny energy ) because it's the ONLY PATH possible. All others are prevented by dielectrics.

The exact same dynamic occurred when the load was cut to DEFECTIVE autoformers that were components of an UNGROUNDED Service.

This voltage boost is quite impossible if the Service is grounded. Said grounded conductor merely bleeds the back-EMF -- the decay energy -- away. 

The long tale told above comes directly from the foundational history of EUSERC -- as reported in one of the industry's trade rags. Sorry, lost the link.

One fine day, I'll stumble upon it, again.

The entire, strange affair was so _odd_ that it's been written up more than once.

And for the last time: it was the LAST thing the EEs expected. It surprised the entire power industry. 

Now-a-days you find that across the planet, ungrounded systems are wholly out of favor. You've gotten the story. You just can't believe it. :blink:

http://www.euserc.com/members/our-members?limit=15&start=45

It's high time you genius experts get on the phone and straighten out the eighty utilities that are members of EUSERC. 

They REALLY need to hear it, as they've been wholly mistaken for seventy-years.


----------



## MTW

telsa said:


> And for the last time: it was the LAST thing the EEs expected. It surprised the entire power industry.
> 
> Now-a-days you find that across the planet, ungrounded systems are wholly out of favor. You've gotten the story. You just can't believe it. :blink:
> 
> http://www.euserc.com/members/our-members?limit=15&start=45
> 
> It's high time you genius experts get on the phone and straighten out the eighty utilities that are members of EUSERC.
> 
> They REALLY need to hear it, as they've been wholly mistaken for seventy-years.


:sleep1:


----------



## MTW

meadow said:


> Millions of ungrounded systems still exist, you tell me whats up with that.


Every old mill building, machine shop and manufacturer in my area was ungrounded delta and was that way for many decades before the wye system took over. 

There's even one totally oddball 600 volt open delta serving a small machine shop still operating that I drive by on occasion. I'll be the poco will be happy when they can eliminate that service. :laughing:


----------



## JW Splicer

2) The ungrounded circuit historically has been selected for those systems where service continuity is of primary concern. See Fig. 3. for examples. The perception is that ungrounded systems have higher service continuity. This is based on the argument that the ground fault current is small and that negligible burning or heating will occur if the fault is not cleared. Therefore line-to-ground faults can be left on the system until it is convenient to find and clear them. This perception has some validity if one limits the criterion to “bolted” or “hard” faults. However, in industrial electrical systems, the vast majority of all faults start as low level arcing ground faults. When arcing ground faults are considered, the following conditions surface—but are seldom addressed.
• Multiple ground faults
• Transient overvoltages
• Resonant conditions
Multiple ground faults can and do occur on ungrounded systems. While a ground fault on one phase of an ungrounded system does not cause an outage, the longer the ground is allowed to remain the greater is the likelihood of a second ground occurring on another phase because the unfaulted phases have line-to-line voltage impressed on their line-to- ground insulation. The insulation is overstressed by as much as 73 percent. Also, there is an accelerated degradation of the insulation system due to the collective overvoltages impinged upon it, through successive ground-faults over a period of several years.
Transient overvoltages due to restriking or intermittent ground faults can and do develop substantial overvoltages on ungrounded electrical systems with respect to ground. There have been many documented cases within industry where multiple equipment failures (e.g.-motors) over an entire 480 V system have occurred while trying to find and locate a ground fault. Measured line-to-ground voltages of 1200 V or higher in these instances have been reported. In all instances, the cause has been traced to a low-level intermittent arcing ground fault on an ungrounded system.
The mechanism explaining how this occurs is best explained in conjunction with Fig. 4. Under worst case conditions, there is an energy exchange between the system inductance and the shunt capacitance to ground resulting in significant voltage escalation with respect to ground.

http://www.eaton.com/ecm/idcplg?IdcService=GET_FILE&dID=167373

Is this what you're talking about?


----------



## Meadow

MTW said:


> Every old mill building, machine shop and manufacturer in my area was ungrounded delta and was that way for many decades before the wye system took over.
> 
> There's even one totally oddball 600 volt open delta serving a small machine shop still operating that I drive by on occasion. I'll be the poco will be happy when they can eliminate that service. :laughing:



And the majority were fine and will those still in place will continue to be. Nothing is shooting our lightening bolts or sending 100s of thousands of volts into the grid.


The only risk in a few cases is an intermittent arc fault which can cause voltage spikes L-G (from cable capacitance) which can puncture weak insulation, but generally it doesn't happen that often in real life.


----------



## Meadow

JW Splicer said:


> 2) The ungrounded circuit historically has been selected for those systems where service continuity is of primary concern. See Fig. 3. for examples. The perception is that ungrounded systems have higher service continuity. This is based on the argument that the ground fault current is small and that negligible burning or heating will occur if the fault is not cleared. Therefore line-to-ground faults can be left on the system until it is convenient to find and clear them. This perception has some validity if one limits the criterion to “bolted” or “hard” faults. However, in industrial electrical systems, the vast majority of all faults start as low level arcing ground faults. When arcing ground faults are considered, the following conditions surface—but are seldom addressed.
> • Multiple ground faults
> • Transient overvoltages
> • Resonant conditions
> Multiple ground faults can and do occur on ungrounded systems. While a ground fault on one phase of an ungrounded system does not cause an outage, the longer the ground is allowed to remain the greater is the likelihood of a second ground occurring on another phase because the unfaulted phases have line-to-line voltage impressed on their line-to- ground insulation. The insulation is overstressed by as much as 73 percent. Also, there is an accelerated degradation of the insulation system due to the collective overvoltages impinged upon it, through successive ground-faults over a period of several years.
> Transient overvoltages due to restriking or intermittent ground faults can and do develop substantial overvoltages on ungrounded electrical systems with respect to ground. There have been many documented cases within industry where multiple equipment failures (e.g.-motors) over an entire 480 V system have occurred while trying to find and locate a ground fault. Measured line-to-ground voltages of 1200 V or higher in these instances have been reported. In all instances, the cause has been traced to a low-level intermittent arcing ground fault on an ungrounded system.
> The mechanism explaining how this occurs is best explained in conjunction with Fig. 4. Under worst case conditions, there is an energy exchange between the system inductance and the shunt capacitance to ground resulting in significant voltage escalation with respect to ground.
> 
> http://www.eaton.com/ecm/idcplg?IdcService=GET_FILE&dID=167373
> 
> Is this what you're talking about?



Which is mitigated by inserting a resistor with a pass through current higher then the capacitive leakage current. In most high resistance systems the ground fault current is a few amps, but you can make and break a fault all day long without a single voltage spike. Only a 1.73 L-G increase on the un-faulted phases, but that makes no difference. 

But still, IMO its not as common as its made out to be. Virtually ever mill in my area used to have 240 or 480 ungrounded delta, without issue. The electrical rooms would have incandescent lamps wired in series and connected in wye. When one lamp went dim or out and the others bright that would indicated a ground fault. Procedure was to either turn circuits on and off, or to drop a load to the panel ground from an unfaulted phase. Using an amp loop or meter around all 3 phases would indicated which feeder or circuit was faulted if the net current was high. 

I think this, if anything killed of ungrounded and HRG systems, few know how to find a missing ground fault, or even know what the ground detector is trying to say.


----------



## JW Splicer

Yeah, I've seen a butt load of delta services out there... Most older than I, still cookin'. In fact, sometimes we still hook em up that way. The only thing around here that's actually officially dead is two phase services and DC services, but I hear there are still a few out there in San Fran.


----------



## macmikeman

There are still a handful of 120 volt services around Honolulu metro area. You will find a two circuit edison fuse ''service'' up on the exterior header over the side door of said shacks. Two 20 amp fuses. And they daisy chained the service drop from the pole to the closest shack, then eave to eave to serve the next three or four in line up the side of a hill, all duplicates with two circuit 120 volt services. Some things here remind me of rural Puerto Rico.


----------



## telsa

There was a time when working hot was considered normal procedure.

You'll get your a$$ sued into oblivion if you're on the wrong side of luck, today.

%%%

The EUSERC crowd has LEGACY ungrounded Services.

If you pick up PG&E's Green book -- they make it explicit -- NO WAY will they install ANY ungrounded Services -- unless a thorough engineering study validates the need.

This attitude is a embedded in their conditions of service, in black letter ink.

You Canadian// east coast fellas... your Poco has its own standards. Naturally.

{

http://www.electriciantalk.com/f30/3-phase-transformer-3-single-phase-transformers-120017/

qsiguy is being compelled to install a GROUNDED SDS -- to meet UK standards. IMAGINE that. The UK authorities won't accept any other scheme. This demand was the PRIMARY reason why qsiguy even posted up. His original query revolved around how to make his scheme properly grounded. That's all. 

It took JRaef to question why he was not using L-N 230V @ 50 Hz straight off.

I originally queried as to where he was even getting 400 VAC. He never admitted that the install was in England in his OP. (!) I would've thought that such a detail would be up front and center.

But that's typical with all OP. Critical details are ALWAYS missing. This makes most of our responses real poke-in-the-dark stabs. 

Stuff that wouldn't take a minute in person are transformed into real puzzles.

}

I've NEVER made the argument that ungrounded Services don't work. I've never stated that they still don't exist.

I've relayed the considered opinions of the EUSERC crowd that they'd rather have their wisdom teeth pulled than grant an ungrounded Service.

For mills, and the rest, they have NO COMPELLING need for ungrounded service.

Neither did the US military during WWII. They just thought they did. So they spec'd it everywhere -- whereas ungrounded Services only really can be justified for paper mills and other rotary mass production transfer machines -- and chemical plants.

Saw mills don't need ungrounded services. Experience has proven that. 

Then again, new sawmills are a very rare thing.

%%%

The tale was related because it's EUSERC history -- and because ever more Pocos refuse to hook up ungrounded Services. THEY don't think they are safer. :no:

Take it up with the Poco. :thumbsup:

I certainly won't be stopping you from such a request. :laughing:

The OP was the query: ungrounded safer or ...

The Pocos have answered: they now loathe ungrounded Services... Apparently, across the planet. 

Equipment lasts longer, failing components bleed energy into the earth, everything becomes more systematic.

Ungrounded has been voted down.


----------



## Meadow

telsa said:


> There was a time when working hot was considered normal procedure.
> 
> You'll get your a$$ sued into oblivion if you're on the wrong side of luck, today.
> 
> %%%
> 
> The EUSERC crowd has LEGACY ungrounded Services.
> 
> If you pick up PG&E's Green book -- they make it explicit -- NO WAY will they install ANY ungrounded Services -- unless a thorough engineering study validates the need.
> 
> This attitude is a embedded in their conditions of service, in black letter ink.
> 
> You Canadian// east coast fellas... your Poco has its own standards. Naturally.
> 
> {
> 
> http://www.electriciantalk.com/f30/3-phase-transformer-3-single-phase-transformers-120017/
> 
> qsiguy is being compelled to install a GROUNDED SDS -- to meet UK standards. IMAGINE that.
> 
> }
> 
> I've NEVER made the argument that ungrounded Services don't work. I've never stated that they still don't exist.
> 
> I've relayed the considered opinions of the EUSERC crowd that they'd rather have their wisdom teeth pulled than grant an ungrounded Service.
> 
> For mills, and the rest, they have NO COMPELLING need for ungrounded service.
> 
> Neither did the US military during WWII. They just thought they did. So they spec'd it everywhere -- whereas ungrounded Services only really can be justified for paper mills and other rotary mass production transfer machines -- and chemical plants.
> 
> Saw mills don't need ungrounded services. Experience has proven that.
> 
> Then again, new sawmills are a very rare thing.
> 
> %%%
> 
> The tale was related because it's EUSERC history -- and because ever more Pocos refuse to hook up ungrounded Services. THEY don't think they are safer. :no:
> 
> Take it up with the Poco. :thumbsup:
> 
> I certainly won't be stopping you from such a request. :laughing:



You said ungrounded system reach thousands of volts and send surges into the utility. 

Also its already explained why POCOs dont.

Further the US military is far from dumb. They know what they are doing in terms of technology.


----------



## telsa

macmikeman said:


> There are still a handful of 120 volt services around Honolulu metro area. You will find a two circuit edison fuse ''service'' up on the exterior header over the side door of said shacks. Two 20 amp fuses. And they daisy chained the service drop from the pole to the closest shack, then eave to eave to serve the next three or four in line up the side of a hill, all duplicates with two circuit 120 volt services. Some things here remind me of rural Puerto Rico.


My old buddy Ray had a cottage along the slopes of Punchbowl.

His Service was 120 VAC -- which at first I couldn't believe. (~1927)

For Mainland guys, they can't imagine how LOW the electric demand is for a cottage that needs only lights -- and -- of late -- a simple refrigerator. Plus a dinky receptacle run -- that doesn't get much use. ( The oven uses SNG. ) The home has no heat, no air conditioning, no insulation. (!)

THAT'S IT. :laughing:


----------



## telsa

meadow said:


> You said ungrounded system reach thousands of volts and send surges into the utility.
> 
> Also its already explained why POCOs dont.
> 
> Further the US military is far from dumb. They know what they are doing in terms of technology.


Wrong, wrong, wrong.

THEY said that they detected astounding voltages kicking back up the line.

THEY said that they lost an IBEW lineman to such shocks.

You are shooting the messenger.

I was never an eye witness. I'm only reporting what trades reporters established as the foundational rationale for EUSERC. 

It got started with this... and then expanded to Service standards, generally. 

Take ALL of your logic up with EUSERC. It's THEIR tale. Not mine. :thumbsup:

Until I read it, I never would've imagined it. :blink:

No, I don't come up with these things on my own. Keep that in the back of your head. :no:

Now a days, by their terms of service, it's BRUTALLY difficult to get any EUSERC Poco to provide ungrounded Service. 

Since you're not a west coast guy... it figures to be all new to you.

So?


----------



## telsa

EUSERC was never founded because the Pocos wanted more wire-bending space.

It was founded because line men were being killed. That was not happening with dead Service hook-ups.

It was happening because voltages not expected were zapping them, dead.


----------



## Meadow

telsa said:


> Wrong, wrong, wrong.
> 
> THEY said that they detected astounding voltages kicking back up the line.
> 
> THEY said that they lost an IBEW lineman to such shocks.
> 
> You are shooting the messenger.
> 
> I was never an eye witness. I'm only reporting what trades reporters established as the foundational rationale for EUSERC.
> 
> It got started with this... and then expanded to Service standards, generally.
> 
> Take ALL of your logic up with EUSERC. It's THEIR tale. Not mine. :thumbsup:



And how do you know their correct? Tell you what, if you can show me evidence then I will say you are right. 






> Until I read it, I never would've imagined it. :blink:
> 
> No, I don't come up with these things on my own. Keep that in the back of your head. :no:


Ok, thats nice to know :thumbsup:



> Now a days, by their terms of service, it's BRUTALLY difficult to get any EUSERC Poco to provide ungrounded Service.
> 
> Since you're not a west coast guy... it figures to be all new to you.
> 
> So?


That part is true.


----------



## Almost always lurkin

I politely request clarification on one point. OK, I've got the picture of a shorting transformer rewiring itself and putting sudden current spikes on the secondary causing voltage surges on the primary. Those surges are going to be phase-to-phase, not common mode like, for example, a lightning strike. How does connecting the system to dirt help with a phase-to-phase voltage spike?


----------



## telsa

Almost always lurkin said:


> I politely request clarification on one point. OK, I've got the picture of a shorting transformer rewiring itself and putting sudden current spikes on the secondary causing voltage surges on the primary. Those surges are going to be phase-to-phase, not common mode like, for example, a lightning strike. How does connecting the system to dirt help with a phase-to-phase voltage spike?


In a Wye (grounded system) the excess energy has a path to ground.

Back-EMF is fighting the forward flow of the voltage all the time.

It only jolts back the line when it has NO WHERE ELSE TO GO.

The coil circuit in the post above is a classic design that forces the current to high voltage and forces it to jump // spark. That action is the only way that the energy of the collapsing field can be discharged.

So now imagine that an alternate path -- a second lead -- is tapped off of the automotive coil -- and bonded to the chassis of the motor. Yep, the spark plug will NEVER fire. The voltage coming out of the coil never even rises in the first place.

It's similar to having a staggering leak in a hydraulic system. Its pressure can't build, either. The energy // pressure takes the easy way out.

%%%

The energies are LOW. They occur as jolts, just the one burst. Just like an automobile coil that only fires once. 

In that sense, they are like having an alien power source stacked on top of the infinite bus.

It's the voltages that spike high... and only when the devices are failing. 

Correctly functioning transformers // autoformers were not the problem.

This is a real tail wags dog situation. 

In a Wye system, such jolts -- mathematically -- look just like an unbalanced load. 

The actual math is daunting - -a headache, really -- see:

2-48 Fink & Beaty :: Standard Handbook for Electrical Engineers.

Back-EMF pulses are identical in circuit impact to an unbalanced load. 

( As the jolt provides alien energy that removes load from the infinite bus -- but only for the once. Transient conditions bring on the worst mathematical puzzles. And you never get paid to resolve them. )

Remember that wave forms are additive. So that -- conceptually -- you can forget the infinite bus and just ask: if a pulse of energy // voltage existed around a grounded Wye system where would it go?

Say juice is coming back on X1 and X3... a phase to phase jolt.

Answer: it'd drain straight into the Earth... via X0 which would be linking both.

{ The entire basis of Fourier calculations is based upon adding wave forms. }

%%%

BTW, not only is EUSERC against ungrounded Services...

It's hard to get new center-tapped delta Services out of them, either. 

They've standardized on Wye Services and are tearing out every other type at every opportunity. It's a fixation with EUSERC.

Such a fetish makes life very easy and predictable for their line crews.

IBEW line crews love EUSERC standards so much that no utility has ever left the standards committee. It just keeps expanding like the blob. :laughing:


----------



## chicken steve

telsa said:


> IBEW line crews love EUSERC standards so much that no utility has ever left the standards committee. It just keeps expanding like the blob. :laughing:


That's just another poco doctrine Telsa

you can ring many up, big whoop....

The thing about parallel paths and/or subsequent AIC really boils down what earthing system is being utilized.

Now ask why.....

Then ask how a SWER factors in

~CS~


----------



## MTW

telsa said:


> In a Wye (grounded system) the excess energy has a path to ground.
> 
> Back-EMF is fighting the forward flow of the voltage all the time.
> 
> It only jolts back the line when it has NO WHERE ELSE TO GO.


Please do us all a favor and stop pretending that like you know what you're talking about. Nobody is buying your act.


----------



## macmikeman

telsa said:


> My old buddy Ray had a cottage along the slopes of Punchbowl.
> 
> His Service was 120 VAC -- which at first I couldn't believe. (~1927)
> 
> For Mainland guys, they can't imagine how LOW the electric demand is for a cottage that needs only lights -- and -- of late -- a simple refrigerator. Plus a dinky receptacle run -- that doesn't get much use. ( The oven uses SNG. ) The home has no heat, no air conditioning, no insulation. (!)
> 
> THAT'S IT. :laughing:


And that house doesn't have any ''grounding'' either. Unless somebody added it on later. The old 120's are a billion volt counter emf nightmare waiting to happen..................


----------



## chicken steve

*Is there a Brit in the house?*

Methinks the term '_grounded'_ & '_ungrounded'_ isn't expressed well here.

For instance, we have a noodle common to _both_ sides of the poco Xformers all the way back to their substations inclusive of every ground rod & water pipe along the way.

There is_ nothing_ SDS about it, it isn't how (for ex) any of us would install the average step down 480/277 --208/120

To my understanding (_admittedly fledgling at best_) the evolution from poco deltas to wye was due to exponential use imposing on ailing infrastructure

Which brings me to the Britt's , and their system(s) . They known their systems because they have to deal with, _monitor_ and _meter_ their systems

We _rarely_ do ....

The epiphany follows along with colorful colloquialisms when our aforementioned 'merican poco grounding system is revealed to them

~CS~


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## Big John

I work on a lot of ungrounded systems, I agree with _ponyboy _that they aren't for personnel safety, they just offer more continuity of service if qualified people maintain them.

The problems are that half the time qualifed folks aren't maintaining them, and they are running with a constant ground fault.

The other problem is during some types of faults, called "restriking faults" you can develop high transient voltages on the system. Only ever seen it once, but it blew out a whole bunch of equipment windings and was really expensive to fix. HRG would have been a much better solution


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## hardworkingstiff

MTW said:


> Please do us all a favor and stop pretending that like you know what you're talking about. Nobody is buying your act.


He claims to be a polymath and I tend to believe him. Granted he gets a bit carried away but I bet that's a common trait among these type of people.

I'm glad he's here, and you always have the "ignore" option.


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## Meadow

hardworkingstiff said:


> He claims to be a polymath and I tend to believe him. Granted he gets a bit carried away but I bet that's a common trait among these type of people.
> 
> I'm glad he's here, and you always have the "ignore" option.




You Shouldn't believe him. 2/3 the stuff he posts is incorrect. He may be able to fool you but not others. Im still waiting for an explanation how wave physics explain an open neutral and ungrounded systems send power back into 13800 volt distribution.


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## Meadow

telsa said:


> In a Wye (grounded system) the excess energy has a path to ground.
> 
> Back-EMF is fighting the forward flow of the voltage all the time.
> 
> It only jolts back the line when it has NO WHERE ELSE TO GO.
> 
> The coil circuit in the post above is a classic design that forces the current to high voltage and forces it to jump // spark. That action is the only way that the energy of the collapsing field can be discharged.
> 
> So now imagine that an alternate path -- a second lead -- is tapped off of the automotive coil -- and bonded to the chassis of the motor. Yep, the spark plug will NEVER fire. The voltage coming out of the coil never even rises in the first place.
> 
> It's similar to having a staggering leak in a hydraulic system. Its pressure can't build, either. The energy // pressure takes the easy way out.
> 
> %%%
> 
> The energies are LOW. They occur as jolts, just the one burst. Just like an automobile coil that only fires once.
> 
> In that sense, they are like having an alien power source stacked on top of the infinite bus.
> 
> It's the voltages that spike high... and only when the devices are failing.
> 
> Correctly functioning transformers // autoformers were not the problem.
> 
> This is a real tail wags dog situation.
> 
> In a Wye system, such jolts -- mathematically -- look just like an unbalanced load.
> 
> The actual math is daunting - -a headache, really -- see:
> 
> 2-48 Fink & Beaty :: Standard Handbook for Electrical Engineers.
> 
> Back-EMF pulses are identical in circuit impact to an unbalanced load.
> 
> ( As the jolt provides alien energy that removes load from the infinite bus -- but only for the once. Transient conditions bring on the worst mathematical puzzles. And you never get paid to resolve them. )
> 
> Remember that wave forms are additive. So that -- conceptually -- you can forget the infinite bus and just ask: if a pulse of energy // voltage existed around a grounded Wye system where would it go?
> 
> Say juice is coming back on X1 and X3... a phase to phase jolt.
> 
> Answer: it'd drain straight into the Earth... via X0 which would be linking both.
> 
> { The entire basis of Fourier calculations is based upon adding wave forms. }
> 
> %%%
> 
> BTW, not only is EUSERC against ungrounded Services...
> 
> It's hard to get new center-tapped delta Services out of them, either.
> 
> They've standardized on Wye Services and are tearing out every other type at every opportunity. It's a fixation with EUSERC.
> 
> Such a fetish makes life very easy and predictable for their line crews.
> 
> IBEW line crews love EUSERC standards so much that no utility has ever left the standards committee. It just keeps expanding like the blob. :laughing:



Show us the math please. Dont be afraid of me not understanding it, that we will figure out latter.


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## hardworkingstiff

meadow said:


> You Shouldn't believe him. 2/3 the stuff he posts is incorrect.


Wow, I guess that does not speak well of me.


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## Meadow

hardworkingstiff said:


> Wow, I guess that does not speak well of me.



Ok, then you must know how an ungrounded secondary sends high voltages into a 13800 volt primary.


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## hardworkingstiff

meadow said:


> Ok, then you must know how an ungrounded secondary sends high voltages into a 13800 volt primary.


No, but I was referring to the 2/3 incorrect comment you made.


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## Meadow

hardworkingstiff said:


> No, but I was referring to the 2/3 incorrect comment you made.



Ok, 100% of the time :laughing:


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## Almost always lurkin

Big John said:


> snip
> The other problem is during some types of faults, called "restriking faults" you can develop high transient voltages on the system.
> snip


Big John, Is a "restriking fault" the same things as https://en.wikipedia.org/wiki/Transient_recovery_voltage? What's the mechanism by which being connected to a planet prevents the problem? 

I second Meadow's request for math. I can easily have someone with a physics degree look it over.


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## Big John

Almost always lurkin said:


> Big John, Is a "restriking fault" the same things as https://en.wikipedia.org/wiki/Transient_recovery_voltage? What's the mechanism by which being connected to a planet prevents the problem...?


 You're getting outside my pay grade, I can't swear those are the same thing.

My basic understanding of what is happening with a restriking fault is that the system capacitance is creating a voltage relative to ground each time the arc extingishes, so when the sine wave of the utility voltage starts climbing again, the system voltage is now utility plus capacitance. By grounding the system you are ensuring the voltage can never be higher than what is present across the supplying transformer winding.

As far as TRV the only thing I know that sounds similar is there is a problem with vacuum interrupters where the can open so quickly that the reactive power in the circuit does not have time to dissipate through an arc. As a result the voltage across the contacts has a huge rise time and either flashes over or destroys system insulation. This is just a type of "inductive kick" though.


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## RIVETER

chicken steve said:


> Decaying Magnetic Flux............can't even google it....~CS~


It means going down.


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## RIVETER

Zog said:


> Right, what is being used now where ungrounded systems used to be used are HRG systems, best of both worlds.


I am inclined to think that a hi-impedance ground is better than a hi resistance ground because the HRG is a 24/7 I/2R loss.


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## chicken steve

RIVETER said:


> I means going down.


Yes it does Riv...

It was the answer we received after an incident where a disco blew up shutting off a larger 480 motor.

Previously i would have thought equipment does that _closing_, not _opening_ switch gear....

~CS~


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## RIVETER

chicken steve said:


> Yes it does Riv...
> 
> It was the answer we received after an incident where a disco blew up shutting off a larger 480 motor.
> 
> Previously i would have thought equipment does that _closing_, not _opening_ switch gear....
> 
> ~CS~


I have only experienced the phenomena when installing a very large inductive load of lighting. If the system is protected properly it should just trip the protective equipment...not BLOW IT UP..:thumbsup:


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## chicken steve

The entity who imparted it has a lotta alphabet after his name Riv

~CS~


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## MTW

meadow said:


> Show us the math please. Dont be afraid of me not understanding it, that we will figure out latter.


You won't be getting any math or any proof from him because he's just trolling.


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## Meadow

chicken steve said:


> Yes it does Riv...
> 
> It was the answer we received after an incident where a disco blew up shutting off a larger 480 motor.
> 
> Previously i would have thought equipment does that _closing_, not _opening_ switch gear....
> 
> ~CS~



I wonder if the regenerative nature of the load could have also done it? Some motors will act like a generator when power is cut to them.


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## Meadow

MTW said:


> You won't be getting any math or any proof from him because he's just trolling.



I dont think we need any, he has successfully proven his degree in trolling :laughing::thumbsup:


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