Strange AC Power Issue

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rshayes
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Post by rshayes » Sat Aug 18, 2007 5:55 pm

The code is quite clear.

Additional grounds from neutral to ground are expressly forbidden on the LOAD side of the disconnect device with three possible exceptions. "Harmonic currents" are not one of the exceptions.

The "line" or "supply" side has different rules that do not apply to the load side.

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Chris Smith
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Post by Chris Smith » Sat Aug 18, 2007 6:08 pm

Not even close.

Not even on planet earth.

Grounded Neutral Conductor. Where the system bonding jumper is installed at the secondary system .....

And then well, the equipment bonding, how you going to avoid that one.

There is not one single mention of the word FORBIDDEN + neutral grounds, so do try again, cant wait to read it, Im sure you know where that was exactly?

Good luck.

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Chris Smith
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Post by Chris Smith » Sat Aug 18, 2007 6:48 pm

..

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haklesup
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Post by haklesup » Sat Aug 18, 2007 6:52 pm

I had a little trouble with the term "Standard Practice" as this has a very specific meaning in the technical community. Just to be clear:

Common Practice = Many people do it but it says nothing about its technical merit. In some cases it works in others its just black majic.

Standard Practice = An accepted way of doing things that has been standardized by a universally accepted body. In this case it would be the NEC and local code ammendments.

Best Practice = A way of doing things that is generally better than standard practice. All aspects of standard practice are applied then one can exceed specifications such as using larger wire or higher quality components. You generally can't negate anything that is spec'd in the NEC or component installation instructions.

I don't have a 20 year old copy of the NEC but I suspect Chris's ground spike solution may have been standard practice at one time, it definately is not now. A city inspector would probably ignore it since it would not be subject to any current permits and thus grandfathered. If Chris were to get a permit for a complete rewire, that solution would not pass today. A home inspector would possibly note the condition as an anomaly but unless there is more wrong than discussed, wouldn't require a change.

For a shop (I guess is an outbuilding) the solution is fine but a better practice does exist.

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Chris Smith
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Post by Chris Smith » Sat Aug 18, 2007 7:04 pm

I wont debate "Grey" areas, and I wont debate the newer codes.

They make laws, .....end of story. [there is a reason, make it better]

What I can say is the system isnt perfectly sound even today as a requirement.

[Im sure its still not?]

Im sure the laws and codes want to move on, thus they expect the situation to be perfect at sales, or better than yesterday.

BUT.....as nothing is perfect....

IT Only makes sense.

My last work in Hollywood and other locations was in the 90s not the 80s, so the code hasn’t changed that much.

Hi rise building such as SONY still needed “neutrals to groundâ€

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Post by avatar_d » Sat Aug 18, 2007 8:36 pm

It's guys like Chris that drove me from usenet a few years ago. Having to wade through senseless babble like that is a waste of time and bandwidth.
His rantings are...well...just that.
Anyway, from my 25 years experience, the ground rod driven into the ground is a reference point for the transformer feeding the residence, equipment, etc. As has been previously stated, this ground rod is a relatively poor conductor of electricity - measuring in the 10's to 100's of ohms, depending on soil conditions and moisture. This is precisely the reason that NEC does not want load current flowing through this connection as any appreciable current flowing through this ground rod will raise the voltage on that ground connector. (Chris, this is an application of Ohm's law, if you're interested) If there is a fault current present on the ground wire due to a shorted motor, damaged wiring or some other abnormal condtion, the current must return to its source, i.e. the transformer. (Chris, this is the definition of a circuit. Be sure to google it). In returning to the transformer, no appreciable current will flow through the ground rod - causing a rise in voltage on the ground conductor. If the ground rod were not present or the neutral and ground jumper missing as was the original post, then the neutral would "float" with respect to anything that was grounded such as a water pipe or concrete floor. This is a dangerous situation which could allow a person to receive a nasty shock if they came into contact with a "real" ground and the "floating ground".

I think that Chris's solution is inheritantly dangerous as it ignores the real problem and allows the possibility of someone receiveing a possibly lethal shock should a fault occur in an applience, cable, or other device.

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Chris Smith
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Post by Chris Smith » Sat Aug 18, 2007 9:46 pm

Instead of calling it rants,.... try calling it the truth.

[The clique calls you]

Instead of giving us rhetoric,.... try a spice model, Thevenin’s theory, CAD, or any other method will do.

Dont cry either when you fall on your face.

#####

Some specific conditions are provided where grounding connections to grounded conductors are permitted, but they are restrictive.

Ask any translator?

All I hear is opinions, .....not one iota of actual reasons it cant or wont work, BS codes that isnt even close, smoke screens, and well, garbage.

I don’t give a flying **** what you think, its simple,... learn or shut up.

Extra ground connections are like two seat belts, stop pretending we have rocket science here and wake up, learn, and then move on.

Any one can be ignorant, whats your excuse here?

Its not even a debate.

Other threads are a joke because their negativity is allowed to thrive despite the evidence to the contrary.

Its no wonder we are right up there with Albania and its education.

Wake up, your haven’t even begun to think.

Having been in soo many dozens of class rooms, Negativity always tries to teach and take over.

And it called ignorance.

Im insecure, you stick with me.

DUHHH [Go away]

Let it take charge, and your just another fool.



What is the old saying....Go pee in some one else’s ear and tell them its raining.

Nothing you do or say will change history, the code, or the law.

Get used to it.

IF you must pee, [Actual words or evidence to the contrary, not just more misreadings] print it in Black and White and stop wasting every ones time and just do it, and save the talk for the some one who cant learn.

The concept that negativity and ignorance is the way to learn went out with the church and Galileo, Copernicus, and soo many others.

There is ZERO on your side, [other than a clique] so abandon ship ASAP.

When are you going to wake up, when Philba says so?

rshayes
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Post by rshayes » Sat Aug 18, 2007 10:19 pm

"All I hear is opinions, .....not one iota of actual reasons it cant or wont work, BS codes that isnt even close, smoke screens, and well, garbage."

Are you sure that this is what the Lassen County building inspector would say if I asked them?

The National Electrical Code is an opinion?
It is a BS Code?
The NEC is a smoke screen?
The NEC is garbage?

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Chris Smith
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Post by Chris Smith » Sat Aug 18, 2007 10:44 pm

Lets consider Rshayes post to Nuts and volts forum, VS his amateur status and speculations?

Im sure he was in print at least 60 times over in the last decade or so,.... so much so that his word is equal to mine or better on all these subjects?

[were waiting for any claim by you,...no?]

Then aside from the simple facts, He has worked construction, he has advised, and he has retro fitted all sort of construction jobs, meaning he has the upper hand, and he is not just full of hot Air?

Waiting?

Any one can read a book, few can understand it, you being in the latter of both.

You have no experience in the electrical trade, nor have you even been accepted into a magazine like NV for a single answer in their forum, and even if you have tried, try 60 plus?

Im sure you wanted to say?

But no one listened?

In short both examples show that your HOT air is just a balloon on its way to some where else.

And PS, nothing in the NEC contradicts me, only you.

And before you decide to waste every ones time, just print where it says “forbiddenâ€

rshayes
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Post by rshayes » Sun Aug 19, 2007 3:26 am

Quoting Chris:

"Lets consider Rshayes post to Nuts and volts forum, VS his amateur status and speculations?

Im sure he was in print at least 60 times over in the last decade or so,.... so much so that his word is equal to mine or better on all these subjects?

[were waiting for any claim by you,...no?] "

My word is certainly better than yours on this subject. I happen to be an Electrical Engineer. I am quite capable of reading and understanding the National Electrical Code. You do not apppear to be capable of this, based on your posts on this subject.

I have not published anything in Nuts & Volts in the last decade. I have, however, been granted several US patents in that time.

I think that this covers my "amateur status and speculations".

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MrAl
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Post by MrAl » Sun Aug 19, 2007 7:31 am

Chris Smith wrote: <snip>
Some specific conditions are provided where grounding connections to grounded conductors are permitted, but they are restrictive.
<snip>
Hi again,


Chris and/or rshays, just what are the 'restrictions' they are talking
about here?
LEDs vs Bulbs, LEDs are winning.

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Chris Smith
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Post by Chris Smith » Sun Aug 19, 2007 7:46 am

Pure fantasy writings and wishful thoughts, no where in the code 250.24(A)(5). does it say “forbiddenâ€

rshayes
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Post by rshayes » Sun Aug 19, 2007 2:06 pm

"Pure fantasy writings and wishful thoughts, no where in the code 250.24(A)(5). does it say “forbiddenâ€

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Chris Smith
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Post by Chris Smith » Sun Aug 19, 2007 2:44 pm

Were still waiting.

You said you could read the code, how about producing it, or was that extra points when you did your exam?

Any Apprentice who becomes a Journey Man, then a E.E. that is worth his weight in salt wouldn’t be wasting everyone time with fantasy, they would pull out their book or go to the web and as they say, “put up or shut upâ€

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MrAl
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Post by MrAl » Sun Aug 19, 2007 2:49 pm

Hi again,

I hate to interrupt this now interesting discussion, but i was thinking
about what Robert had said about the relatively high ground resistance.

Back when i was 10 years old or so, we used to go back in the garden
(fairly large) early in the morning when the grass was still wet.
We would use one of those devices for getting big worms to come
up to the surface so you can grab them by hand and later use them
for bait for fishing. The device was simply two poles with insulating
handles and two copper rods attached to two wires that had a 120vac
plug on the other end. You stick the two rods into the ground
(maybe about 12 to 24 inches depth) and then plug the unit into
a 120vac receptical, which was a very long extension cord.

Point is, even when the two rods are stuck into the ground only
24 inches apart or so and the unit is plugged in, the breaker does
not trip. At the time we had 15 amp breakers, so that means that
less than 15 amps was flowing, which in turn means that the
total resistance between rods was around 8 ohms (given some
10 volts drop in the long extension cord and 14 amps max).
Using simple math, this means the resistance from one rod to
ground was 4 ohms, given that the ground rod for the house
was very poorly installed, or 8 ohms if it happened to be good
that early in the morning when the ground was damp.
Even with 4 ohms however, that would be quite a high resistance
for a neutral wire i think, and it was probably higher than that
because im sure that thing didnt draw anything near 14 amps.

In any case, there is good reason to believe that any ground rod
installation can be or become a rather high resistance depending
on water table and even how the ground water changes over time.
Sometimes areas get wetter but some areas (like the very location
i was talking about) become drier over the course of 20 or so years.
This would basically say that the ground fix for a neutral wire would
be a temporary fix, with the life expectancy to be determined by
the geographical location as well as the change in moisture content
over time and any change in rod diameter based on possible
small asymmetric current flow from an apparatus in the ground wire
or just loss of material from plain rusting.
LEDs vs Bulbs, LEDs are winning.

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