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-   -   interesting question: what if there is no bonding between ground and neutral? (https://www.electriciantalk.com/f2/interesting-question-what-if-there-no-bonding-between-ground-neutral-160497/)

mike883 05-28-2016 01:07 PM

interesting question: what if there is no bonding between ground and neutral?
 
we all know we need to bonding the ground and the neutral in the system, either inside the transformer or at the first service point, in this way, the ground can use the bonding point then return to the transformer as a loop

an interesting question is what if there is no bonding between ground and neutral, then the ground can return to the transformer, then there is no complete loop

in this situation, if the ground touch the hot, what will happen? ground fault, short circuit?

don't forget there is no complete loop of the ground

RePhase277 05-28-2016 01:10 PM

All the toilets in the building begin swirling the other direction.

MTW 05-28-2016 02:15 PM

If the ground is not connected back to the source somehow (via the neutral), then there is no fault path back to the source. In the event of a fault, the ground would then simply float with a lethal voltage on it until someone gets shocked and notices it, or something much worse happens.

Majewski 05-28-2016 05:47 PM

Muder death kill. Complete anarchy....unless you never ever touch it or metal connected to it.

Majewski 05-28-2016 05:48 PM

Quote:

Originally Posted by InPhase277 (Post 2843913)
All the toilets in the building begin swirling the other direction.

Also this, like in the Simpsons.

macmikeman 05-28-2016 06:10 PM

Whatever the you do, don't push the doorbell button. It is a danger beyond belief, a two wire and no ground hazard. Remember it only takes .006 amps of stray current to fib the heart muscle. All them current and past code panel members should be shot and then tossed into prison for allowing this tragedy to continue.

MikeFL 05-28-2016 07:35 PM

That ground rod is to return a lineside transient back to the POCO and keep it out of your house. Open that connection and you your house starts smoking.

macmikeman 05-28-2016 07:38 PM

Quote:

Originally Posted by MikeFL (Post 2844921)
That ground rod is to return a lineside transient back to the POCO and keep it out of your house. Open that connection and you your house starts smoking.

Gee I'm sorry to tell you this but electricity follows all paths back to the source. I don't agree with you're statement.

emtnut 05-28-2016 09:06 PM

Quote:

Originally Posted by mike883 (Post 2843889)
we all know we need to bonding the ground and the neutral in the system, either inside the transformer or at the first service point, in this way, the ground can use the bonding point then return to the transformer as a loop

an interesting question is what if there is no bonding between ground and neutral, then the ground can return to the transformer, then there is no complete loop
Do you mean the ground can't return to the Tx ?

in this situation, if the ground touch the hot, what will happen? ground fault, short circuit?

don't forget there is no complete loop of the ground

Apart from the earth ?


What do you think would happen ?

Would some current make it back to the Tx ?
Is the soil moist/do we know the resistance of the ground ?
Are there ground rods at the service AND the Tx ?
What voltage are we talking about ?
You mentioned ground fault .... Is this an ungrounded system ?

sbrn33 05-28-2016 09:49 PM

Once again, a decent question from the OP and a bunch of asshole responses from the supposedly "smart" guys.

Big John 05-28-2016 10:00 PM

Quote:

Originally Posted by MikeFL (Post 2844921)
That ground rod is to return a lineside transient back to the POCO and keep it out of your house. Open that connection and you your house starts smoking.

Eh? Utility already grounds their trannys. Opening the customer ground doesn't change how the transformer operates, it just increases the local neutral-earth potential.

Even if it were to completely float an ungrounded system isn't gonna automatically smoke anything.

spinninwheels 05-28-2016 10:19 PM

Quote:

Originally Posted by mike883 (Post 2843889)
we all know we need to bonding the ground and the neutral in the system, either inside the transformer or at the first service point, in this way, the ground can use the bonding point then return to the transformer as a loop

an interesting question is what if there is no bonding between ground and neutral, then the ground can return to the transformer, then there is no complete loop

in this situation, if the ground touch the hot, what will happen? ground fault, short circuit?

don't forget there is no complete loop of the ground

So I presume this is a grounded system that has had the grounding conductor disconnected from the xo in the xfmr, or disconnected from the grounded conductor in the main panel. Yes?

Is the bonding system still complete to the neutral bus in the main panel, or the xo still connected to the bonding system?

When you say the ground touches the hot, do you mean the bonding conductor, or part of the bonded system; or do you mean the grounding conductor?

I remember when I was in school, and the instructors would always give these scenarios of possibly faults, and shock potential hazards.

MikeFL 05-28-2016 10:50 PM

Quote:

Originally Posted by Big John (Post 2845321)
Eh? Utility already grounds their trannys. Opening the customer ground doesn't change how the transformer operates, it just increases the local neutral-earth potential.

Even if it were to completely float an ungrounded system isn't gonna automatically smoke anything.

I don't see the word transformer in my post.

MikeFL 05-28-2016 10:57 PM

Quote:

Originally Posted by macmikeman (Post 2844929)
Gee I'm sorry to tell you this but electricity follows all paths back to the source. I don't agree with you're statement.

Pretty bizarre interpretation there Pineapple.

Where in my post did I say it's the only path? The noodle is the primary path. A basic DC circuit shows us electricity takes all paths.
So where's your magic?

macmikeman 05-28-2016 11:06 PM

Quote:

Originally Posted by MikeFL (Post 2844921)
A neutral conductor is to return a lineside transient back to the POCO and keep it out of your house. Open that connection and you your house starts smoking.

There will be multiple paths back to the poco and each will carry current according to its impedance, ground being one path provided the voltage is high enough to overcome impedance of earth. . If an ungrounded line conductor is delivering the surge it will follow all connected loads throughout the building and return on the neutral conductor (smoking the house in the process as it were...). If there is a good quality grounding system it will also deliver a portion of the current at elevated voltage thru the earth if the voltage is high enough to overcome the impedance of the earth medium. If there is metal water piping connected to the service neutral , that path also will deliver current back to the poco thru the other connected neutral wires of closeby connected electrical services.

macmikeman 05-28-2016 11:09 PM

And since you call me pineapple, may I in return call you gladiolus flower?

Bad Electrician 05-28-2016 11:17 PM

If there is no neutral ground bond, assuming there is no utility grounded neutral such as in a SDS

You have an ungrounded system.

So the first fault is free. Fault to ground on A phase and you have a grounded A phase no harm no foul. Seen it done several times by hacks.

A-Gnd 0 VAC
B-Gnd 208
C-Gnd 208
A-N 120
B-N 120
C-N 120
A-B 208
B-C 208
C-A 208

If there is no fault the voltage to ground floats based on the impedance of the loads.

MTW 05-28-2016 11:25 PM

Quote:

Originally Posted by Bad Electrician (Post 2845649)
If there is no neutral ground bond, assuming there is no utility grounded neutral such as in a SDS

You have an ungrounded system.

So the first fault is free. Fault to ground on A phase and you have a grounded A phase no harm no foul. Seen it done several times by hacks.

A-Gnd 0 VAC
B-Gnd 208
C-Gnd 208
A-N 120
B-N 120
C-N 120
A-B 208
B-C 208
C-A 208

If there is no fault the voltage to ground floats based on the impedance of the loads.

I don't think the OP is talking about a genuine ungrounded system, I think he's talking about having a grounded system but not bonding the neutral and ground together.

Bad Electrician 05-28-2016 11:51 PM

Quote:

Originally Posted by MTW (Post 2845705)
I don't think the OP is talking about a genuine ungrounded system, I think he's talking about having a grounded system but not bonding the neutral and ground together.

Assuming no metallic connection between the main service and the utility transformer the same would apply.

MTW 05-29-2016 12:04 AM

Quote:

Originally Posted by Bad Electrician (Post 2845777)
Assuming no metallic connection between the main service and the utility transformer the same would apply.

:rolleyes::rolleyes:


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