# Why can't you connect Ground/Neutral bus bars on a sub



## secutanudu (Mar 15, 2009)

Subject says it all. I understand that there can only be one point of connection between the neutral system and ground system (in the main panel).

My question is...why? I can't figure it out.

What would happen if you were to have a shared neutral/ground bus in a sub panel?


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## junkcollector (Nov 25, 2007)

secutanudu said:


> Subject says it all. I understand that there can only be one point of connection between the neutral system and ground system (in the main panel).
> 
> My question is...why? I can't figure it out.
> 
> What would happen if you were to have a shared neutral/ground bus in a sub panel?



You would have parallel paths back to your main panel; your ground would be carrying some of the current that your neutral should be carrying. The ground is normally a non current carrying conductor.


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## Bob Mariani (Dec 1, 2008)

The ground must be clean (no current) to be effective to provide a path of least resistance to protect you from errant currents. In a sub panel the neutral carries current from any unbalanced loads. If you connect the neutral and the ground you have current on the ground, thus not a very good grounded system.


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## DownRiverGuy (Nov 24, 2009)

Ok let's explain this with an example...

Let's assume it's a setup with a properly installed subpanel feeding a load that has some return neutral current (electronic equipment etc.).

3A travels from the outlet neutral to the subpanel neutral buss bar (which is isolated from the ground)
3A travels from the subpanel neutral buss bar to the neutral feeder to the main panel neutral buss bar.
3A travels from the main panel neutral buss bar to the main ground.

So at no point can anyone get shocked from that.

Now what happens if it's a setup with a neutral and ground being shared in a subpanel.

3A travels from the outlet neutral to the subpanel neutral buss bar.
The current then will travel to the ground of the system and will energize anything in the system while it travels back to the ground source. 

Thus in the second method you give current a longer path to ground. and something or SOMEONE may interupt that path :-x


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## secutanudu (Mar 15, 2009)

Got it. Thanks.


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## Giles (Jan 25, 2010)

DownRiverGuy said:


> Ok let's explain this with an example...
> 
> Let's assume it's a setup with a properly installed subpanel feeding a load that has some return neutral current (electronic equipment etc.).
> 
> ...


Does the location if the subpanel matter. If the sub is mounted nex to the main panel as opposed to a sub mounted in a separate building?


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## DownRiverGuy (Nov 24, 2009)

Per the code no. The moment you have a subpanel of any type (regardless of distance) it must have a seperate ground bus and an isolated neutral buss.

What happens if a person falls on the little piece of conduit connecting the two panels together and there is 30A flowing thru it? (I know not likely but still).


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## Jim Port (Sep 21, 2007)

The sticky post by Bruto at the top of this forum explains this very well.


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## Stubbie (Jan 7, 2007)

Giles said:


> Does the location if the subpanel matter. If the sub is mounted nex to the main panel as opposed to a sub mounted in a separate building?


It certainly does matter depending on the code cycle your on. In 2008 the NEC withdrew the exception for a 3 wire feeder to panelboards (sub-panels) in detached buildings where no metallic paths other than the feeder existed, no gfpe, and no feeder equipment ground.
Prior to 2008 if you had a three wire feeder consisting of 2 hots and a neutral then you would bond neutral and ground assuming the installation meets the exception requirements. This is very common to see 3 wire feeders to detached structures, neutral and ground bonded. 

Only on 4 wire feeders to any panelboard would you not bond neutral and ground.

So if your area is still working with a code cycle other than 2008 you can use 3 wire feeders to panelboards in detached structures not having the service equipment if all 3 requirements listed earlier are met.

Below is an example I drew for the sticky mentioned by Jim in post #8 showing the unwanted result of combining neutral and ground in any panelboard served by a 4 wire feeder....


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## dougw (Oct 26, 2010)

Stubbie-
If I have a detached subpanel with only a 3 wire(2 hot and 1 ground) hookup with a bonded neutral/ground, do I still need separate ground rods connected to the ground in the subpanel?.....


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## dougw (Oct 26, 2010)

Stubbie-
Disregard my last question I found your diagrams that explained it perfectly...Thanks-Doug


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## brric (Mar 5, 2010)

DownRiverGuy said:


> Ok let's explain this with an example...
> 
> Let's assume it's a setup with a properly installed subpanel feeding a load that has some return neutral current (electronic equipment etc.).
> 
> ...


Current does NOT normally flow on the grounding system. Current flows back to the source which is usually a transformer.


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## a7ecorsair (Jun 1, 2010)

DownRiverGuy said:


> What happens if a person falls on the little piece of conduit connecting the two panels together and there is 30A flowing thru it? (I know not likely but still).


Nothing would happen. Just because there would be 30A of current doesn't mean there is a difference of potential.


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## sky jumper (Nov 16, 2007)

ok so I understand if neutral and ground are connected at an outlet (or device), ground could become a return path for current. my question is so what? since neutral and ground are tied at the service panel, neutral is always at ground potential. this is AC - so it's the hot that varies +/- 170Vpk above and below ground potential, not the neutral. so what if the chassis of the washing machine is tied to neutral? you and the chassis and neutral are all at ground potential anyway, so nothing will happen. your body's resitance is many magnitudes more than a copper wire, so no current will flow through you even if it does flow through the chassis of the washing machine. 

ok now assume there's a fault in the washing machine (or stove top) that shorts "hot" to chassis - it will blow the circuit breaker immediately, even if neutral is tied to hot. no danger there. 

ok now assume that nuetral is somehow open circuited somewhere in the house (so the chassis is not grounded or tied back to panel neutral) AND AT THE EXACT SAME TIME there just happens to be a fault inside the device that shorts hot to chassis (you see, if either happened first the device would harmlessly stop working, so you'd know something was wrong and get it fixed) -- ok with simultaneous faults (VERY unlikely) you now you have the potential for a hot chassis. BUT why would you assume that a separate ground wire would neccesarily prevent this? I would argue that whatever disruptive action caused the neutral to open (e.g. a contractor's recip saw) would also cut the ground connection to the device (and probably the hot too) since they are all run together. for the life of me I can't imagine a scenario where only the neutral would open circuit AND at the same time a device suffers an internal short to chassis. 

if anyone out there has a real world example of this I'd love to hear it.


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## a7ecorsair (Jun 1, 2010)

Equipment ground is there as a safety factor. Years ago, nothing was grounded and drills, clocks, toaster, table saws, you name it, all worked just fine on two wires.
Do you have a spare tire in you car just in case you need it? I want my metal framed tools properly grounded just in case I need it.....


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## sky jumper (Nov 16, 2007)

the one other comment i'd add is that tying ground to neutral is better than leaving ground open. with an open ground you do have a potential for a "hot" chassis. with gnd tied to neutral at least it will trip the ckt breaker. 

also consider conduit states like Illinois where the ground is distributed through the conduit - not a separate ground wire. for devices such as lighting fixtures this system relies on a ground connection being made through the fixture's mounting screws (unless you go out of your way to actually connect the fixture's ground wire to the outlet box - which nobody does). I installed a ceiling fan this week that had a painted mounting bracket with a ground wire attached to the painted surface (presumably the metallic body of the bracket would receive ground through the mount screws from the outlet box/conduit) but then the painted surface would partially insulate the rest of the fixture! this is not a good ground, and in my opinion is more dangerous than tying neutral to ground.


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## kbsparky (Sep 11, 2008)

WE had a situation where the main bonding jumper screw was loose, so the panel box enclosure, and HVAC ductwork, and metal ceiling grid ended up being "hot" ... it was quite a mess!

This is what can happen when current-carrying circuits are connected to your equipment ground: undesirable currents begin flowing across all kinds of things, that normally should not be carrying juice.

The other thing to consider is electricity does _not_ take the path of least resistance. It takes _all _paths, with the majority of current flowing over the path of least resistance. Some of the current will be flowing over other paths of greater resistance. 

IF you happen to come in contact with one of those paths of current flow, some of it may end up flowing through you, which can range from a mild shock to electrocution, depending on the amount of current flowing.

Keeping your grounds (non-current-carrying) separated from the neutrals (current-carrying) can minimize these hazards.


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## Leah Frances (Jan 13, 2008)

sky jumper said:


> for devices such as lighting fixtures this system relies on a ground connection being made through the fixture's mounting screws (unless you go out of your way to actually connect the fixture's ground wire to the outlet box - which nobody does).


This girl does.


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## Jim Port (Sep 21, 2007)

Skyjumper, I hope you are not advocating that tieing the neutral to ground at a receptacle. Doing so could cause someone to receive a seroius shock or worse. This is called a bootleg ground and could have deadly consequences.


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## a7ecorsair (Jun 1, 2010)

Leah Frances said:


> This girl does.


Orange you a good girl:laughing:


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## sky jumper (Nov 16, 2007)

i'm certainly not trying to get people killed -- I am merely questioning the conventional wisdom of the dangers of tying ground to neutral. with due respect to the licensed electricians here, I have not yet heard a convincing explanation that addresses the questions and scenarios i've outlined. I like to base my opinions on science and an understanding of the physical laws that govern the flow of electricity as opposed to what is spelled out in a code book. 

as you may have guessed I am not a licensed electrician - I am an electrical engineer with extensive training in physics, and this code requirement does not make sense to me - to be clear, I do undestand the need to ground the conducting chassis/surface of a device - but I question the need to provide two separate conducting paths back to panel ground/neutral -- and I do understand the argument to separate current carrying circuits from non-current carrying -- but I question the rationale behind that argument (for the reasons stated in my previous posts). I will readily admit that I do not have much experience "in the field" where untrained handymen and homeowners do things that cause fires and death -- i'm just wondering what those mistakes are because to me it seems the risk here is almost non-existent. even with kbsparky's annecdotal story - how did the hot get shorted to the panel/ducting to beging with and why didn't the main breaker trip as a result? how would a ground connection have prevented it?


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## Daniel Holzman (Mar 10, 2009)

I believe skyjumper has made a very good point, one which seems to have been missed completely throughout this discussion. Current flow through a wire in and of itself is not dangerous even if you touch a bare wire. As he pointed out, current will only flow through YOUR body if you are at a different potential (voltage) than the wire. If the wire is the neutral or the equipment ground, it is by definition connected to the ground at the main panel, so the wire should be very close to ground potential, which by the way is taken to be zero BY CONVENTION, not because there is some magic about the ground truly being at zero voltage.

So let's discuss real world dangerous situations that can arise, and how an independent ground wire actually functions.

Case 1, very dangerous: The hot wire becomes disconnected from the device. In the case of AC current, the potential of the hot wire varies between about +170V and -170V 60 times per second. Assuming you are at ground potential, and have a resistance of 1000 ohms (could be higher, could be lower), and you touch the hot wire, you are going to get a shock due to the RMS voltage potential difference of 120V, and in fact you will get I = V/R = approximately 1/8 amp of current through you, which can be quite dangerous. If you are wet, and your resistance is lower, you will get more amperage, and you could die. Bad news. Note that the presence of an independent equipment ground in this case does not help you out a bit, and note that the breaker will not trip either.

Case 2: The hot wire frays a little, and a small hair of wire touches the frame of the appliance. In this case, the frame of the appliance is going to be at an elevated voltage, likely somewhere close to 120V RMS, because the hot wire is touching it. If there is no independent equipment ground, there will likely be only a very small current flow through the frame, because the neutral is typically not connected to the frame of the appliance, and the frame is probably not connected to ground well or perhaps not at all. However, the frame is still at a relatively high voltage, so if you touch the frame, you will get a shock, due to the voltage difference between the frame and you. Current will flow through the frame, through you, and to ground through you, and if the wire hair is large enough, and you are wet, you could get seriously injured or killed. If there is an independent equipment ground, it will provide a low resistance path back to ground, and by Kirchoffs law, there will be very little (not zero, but very little) flow through you, because your resistance is higher than the equipment ground wire.

Note that if the neutral were connected to the frame of the appliance, the neutral would carry the stray current back to ground with lower resistance than you, so again you would sustain only a small amount of current flow through your body. In fact, you might not notice at all that the frame was energized. And if the hair of the wire is small enough, you will not trip the breaker.

So I believe the main reason for the independent equipment ground is to ground the frame of the appliance, since we typically do not use the neutral to ground the appliance frame any longer. However, with dryers we often ground the frame through the neutral, if we have a three wire plug.


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## Saturday Cowboy (Nov 29, 2009)

With all due respect, you have to have a really good understanding of advanced electrical theory(and i have seen far too many sparkies that don't) to understand why it is not a good idea.(ohm's law, AC theory etc.) Yes we will all admit that in a perfectly wired and working system there is little risk. But that is not a good way to design a system(only safe under ideal conditions). Plus it is code required(for most of us that settles the matter weather we like it or not)

The short of it is you will always have current(in the whole house) where it is not soposed to be. It will find a time and place for it to devolop into a problem.


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## jlmran (Feb 8, 2010)

Simple answer to OP: it violates the code.

What you really meant to ask: why is it a code violation?

Sorry...I get hung up on semantics.


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## Saturday Cowboy (Nov 29, 2009)

sky jumper said:


> kbsparky's annecdotal story - how did the hot get shorted to the panel/ducting to beging with and why didn't the main breaker trip as a result? how would a ground connection have prevented it?


Those things are always connected. The problem came when the ground was lost and because there was something using the ground as a return path or neutral if you will, the ground was hot and instead of "draining" the bootleg current to ground, which it couldn't, it sent the current to everything that the ground was connected to.

I'm guessing that the duct and ceiling where connected to building steel which is required to be bonded.

This link from another post shows how some weird stuff can become energized when monkeying with grounds
http://www.youtube.com/watch?v=EQiMr5Xm2sU&feature=player_embedded


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## sky jumper (Nov 16, 2007)

thanks D Holzman. we speak the same language, and your explanations are spot on I believe. 

the only caveat to our premise that no (or very little) current will flow through one's body when touching a bare grounded/neutral wire is in situations where the wavelength of the energy is comparable to the length of the conductor in question. in such cases you can actually realize a votage gradient along the length of a single conductor. however, the wavelength of 60Hz is something like 3k miles, so that is not at all a concern in household. it becomes a problem with radio frequency (which is where i do all my work).


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## jlmran (Feb 8, 2010)

Bonding neutral and ground bars in a subpanel would result in equipment chassis (serviced by main panel) becoming energized, without a conventional 'fault' occurring.

Being energized doesn't necessarily mean it will shock.


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## 1488rob (Mar 10, 2011)

Iknew you werent electrical skyjumper like all us skydivers we allways want to question things ..why we would never make good lawyers..having to refer to someone elses work. Who are you on dropzone .com?

I have a question towards this.. On my mainpanel of the halfbuilt house I bought both the neutral and ground wires are wired to same buss and it passed. All breakers are on that side. when I add breakers to the left side wil I be able to wire both neutral and ground to the ground buss?, if not.it will be alot of rewiring as theres no space to put wires left on nuetral buss:wink:


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## Stubbie (Jan 7, 2007)

I'm not sure why this is so hard for you to understand. All metal likely to be energized in a ground fault must be bonded. All that metal is readily accessible to touch by humans. You are advocating that all metal should be allowed to have current flowing on it by bonding it to the neutral return path and forgo a non current carrying path constructed separate from the neutral.

If you do this .. neutral current has the potential to flow on all sorts of metal devices and appliances via the connection of a power cord or bonding. If a branch circuit neutral would open (very common) then bonded metal would be a viable path for large amounts of current to use to return to the source. If you do not bond the metal to a separate effective fault path then all that metal comes to line voltage if any of it comes in contact with a ungrounded conductor. Now you definitely have a potential voltage ready to push that current thru you so it can return to the source.

So the point is you do not want current flowing on metal that is easily in contact with human touch or where it is unsuspected by the typical unskilled homeowner or person.

You are not correct to think that because a grounded conductor is at zero potential nothing will happen if you come in contact with metal that is carrying neutral current. Fact is nothing is really at zero potentiall just some floating potential that hopefully is close to zero...earth is a good example of this floating reference.

Also remember that AC current is reversing potential rapidly during a complete cycle of the sine wave. Point being if I disconnected a neutral from a panel neutral bar and told you to take the end of that neutral wire (grounded conductor) in one hand and touch the neutral bar in the panel with the other what do you suspect is going to happen ...? My point being you got to go way out of your way to get in contact with neutral current in a system that is grounded. In an system where there are only 2 wires (hot and neutral) in the branch circuits all metal that is easily touched by humans would become energized at line voltage in the event of a fault because you would not bond it to the neutral. You cannot let neutral current use bonded metal as a return path. To do so puts you at a much higher risk of injury or death.
The exception being dryer and range circuits prior to the 1996 code cycle. These are no longer allowed. These 3 wire circuits are actually pretty safe which supports your argument but in the even of an open in the neutral of the branch circuit you just energized the metal of the appliance. Nothing really happens other than think about touching the dryer chassis then touching the washer chassis , I believe you just gave that neutral current a return path to the source and it is going to use you to get there. It only takes milliamps to kill you not amps and milliamps will flow thru you in that event or any event where you put your body in series with two low impedance paths to the source. A 4 wire branch circuit prevents this event as the bond to the dryer metal is removed from the neutral.

So the idea is to keep neutral current off bonded metal and to bond that metal to a separate effective ground fault path that will let a breaker open the circuit in the event of a hot wire (ungrounded conductor) touching that bonded metal. 

It would be true if I connected bonded metal to the neutral that a breaker will still open on fault to a hot wire ... after all it could care less what wire (ground or neutal) allows enough current to flow thru it to trip open. 

Problem is Ive given the neutral current hundreds of more ways to seek the source that are easily touched by humans that may provide that link. 

Given a normally operating system it really is foolish to bond neutral to bonded metal IMO and the NEC. 

Neutral current will kill you it is nothing to allow out of the walls to places it isn't expected or easily touched.

There are always events that can throw all this out the window such as an open service neutral ... regardless I'd rather have neutral current flowing on insulated conductors than over bare metal that I can easily touch in places I do not expect it. Electricity is dangerous we cannot make it completely safe but we have to limit the possibilities of it being less safe.

Remember to that circuit breakers do not monitor what is going on with the neutral. Just ask a plumber or two that has had a near death experience with unwanted or objectionable neutral current on metal water pipes and drains..

So to summarize you have these choices

Bond neutral to ground and energize all your bonded metal that humans readily come in contact. 

Do not bond metal to neutral and risk line voltage on your bonded metal in the event of a phase fault. 

Bond metal to a separate grounding path that is not part of the neutral current carrying system. Doing so keeps neutral current off bonded metal in places you do not expect it to be and the unsuspecting unskilled person cannot easily come in contact with it... part of the reason you only bond neutral to ground in the service equipment.


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## kbsparky (Sep 11, 2008)

sky jumper said:


> -- i'm just wondering what those mistakes are because to me it seems the risk here is almost non-existent. even with kbsparky's annecdotal story - how did the hot get shorted to the panel/ducting to beging with and why didn't the main breaker trip as a result? how would a ground connection have prevented it?


It was not the hot that was shorted, it was the neutral that was not properly bonded, thus creating the parallel paths of current flowing through the building steel components. The same thing can happen with any sub-panel whose neutral and ground wires are not kept separated.

Anyone standing on a concrete floor, and happened to touch something as innocent looking as the metal ceiling grid was getting zapped, since the neutral current was flowing through that, as well as the metal ductwork of the heating system, etc. Touching the frame of a fridge and an adjacent stainless steel sink would have the same result.

This effect is more pronounced when a rather large load of current is flowing through the neutral, creating a potential difference between the neutral and ground.

Keeping those non-current carrying metal parts separated from the current-carrying neutral conductor is critical in preventing such hazards.


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## AllanJ (Nov 24, 2007)

1488rob said:


> I have a question towards this.. On my mainpanel of the halfbuilt house I bought both the neutral and ground wires are wired to same buss and it passed. All breakers are on that side. when I add breakers to the left side wil I be able to wire both neutral and ground to the ground buss?, :


(correction made) Yes for ground wires, no for neutral wires.

In the main panel the "neutral" bus is (should be) connected (bonded) to the panel using a metal strip or a wire or by having a screw that digs into the back of the panel. The "ground" bus is already bonded by being rigidly fastened to a spot on the back of the panel where the paint was scraped off. (correction made here later) Then it does not make any difference whether ground wires are connected to the "neutral" bus or "ground" bus. Neutral wires must all be connected, one per hole or set screw, to the bus where the fat neutral from the service drop is attached.

Two or more ground wires may be taken off the bus, wire nutted to a pigtail of size equal to the larger(est) of them, and just the pigtail re-attached to the bus to free up holes for other wires. Two or more neutrals may not be so pigtailed although we have seen neutrals congregated on a different bus where a crossbar or fatter jumper wire, sized for the sum of the respective circuit amperages, joins the two busses.


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## a7ecorsair (Jun 1, 2010)

I think we are all in agreement that current wants to return to its source and in fact, it can't go any other place. You can connect a jumper cable from one terminal on your car battery to a grounded rod and nothing will happen. There is no complete circuit.
Residential housing power is feed to the house using a transformer. A transformer provides *isolation* between the primary and secondary side. I other words, the current flowing in the primary winding does not pass to the secondary winding. So, in the case of my house, I have 7200 volts on the primary side and 240 volts on the secondary side.
This transformer is connected to my house by three wires and we all know how this is done. This secondary winding is _*MY SOURCE*_. As I use electricity, current flows in a big loop around this isolated connection between the house and the transformer. Some between the two hots and some returns through the neutral. I don't need a "ground" for this to work. In fact, if I'm standing on ground and touch a hot lead I don't have a return path to my source. Or do I? Here is where the problem starts. The power company, when they installed the transformer, connected a #6 to the transformer case, which is also connected to the centertap of the secondary winding, for lightning protection. This creates a problem for the house wiring. With this ground wire connected to the transformer secondary, *my source*, there is now another return path to the source which has to be dealt with. Also, if lighting hits the transformer, the neutral wire will carry some - a lot - of the current to the main panel where it will find its way to earth through the grounding electrode conductor *which must be landed on the neutral bar*, not the ground bar.


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## WaldenL (Jan 9, 2009)

a7ecorsair said:


> ... find its way to earth through the grounding electrode conductor *which must be landed on the neutral bar*, not the ground bar.


And why is that (I mean electrically, not "because it's code")? After all, the neutral and ground bars should be bonded in the main panel. I can think of two reasons, namely, the bars _should_ be bonded, but may not be, and because the wire bonding the two may not have sufficient current carrying capability. But those are guesses. Why must it be landed on the neutral bar?


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## brric (Mar 5, 2010)

Because the neutral of the service is how the fault current returns to its source which is the transformer.


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## a7ecorsair (Jun 1, 2010)

WaldenL said:


> And why is that (I mean electrically, not "because it's code")? After all, the neutral and ground bars should be bonded in the main panel. I can think of two reasons, namely, the bars _should_ be bonded, but may not be, and because the wire bonding the two may not have sufficient current carrying capability. But those are guesses. Why must it be landed on the neutral bar?


Your second guess is pretty close. It also limits the number of connections between the neutral and the GEC to two.


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## brric (Mar 5, 2010)

a7ecorsair said:


> Your second guess is pretty close. It also limits the number of connections between the neutral and the GEC to two.


 What "two" connections are you referring to?


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## a7ecorsair (Jun 1, 2010)

The neutral wire connection to the neutral bar and the GEC's connection to the neutral bar.


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## brric (Mar 5, 2010)

I see. I didn't understand the "two" as being two conductors connected at "one" point.


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## jlmran (Feb 8, 2010)

a7ecorsair said:


> I think we are all in agreement that current wants to return to its source and in fact, it can't go any other place. You can connect a jumper cable from one terminal on your car battery to a grounded rod and nothing will happen. There is no complete circuit.
> Residential housing power is feed to the house using a transformer. A transformer provides isolation between the primary and secondary side. I other words, the current flowing in the primary winding does not pass to the secondary winding. So, in the case of my house, I have 7200 volts on the primary side and 240 volts on the secondary side.
> This transformer is connected to my house by three wires and we all know how this is done. This secondary winding is MY SOURCE. As I use electricity, current flows in a big loop around this isolated connection between the house and the transformer. Some between the two hots and some returns through the neutral. I don't need a "ground" for this to work. In fact, if I'm standing on ground and touch a hot lead I don't have a return path to my source. Or do I? Here is where the problem starts. The power company, when they installed the transformer, connected a #6 to the transformer case, which is also connected to the centertap of the secondary winding, for lightning protection. This creates a problem for the house wiring. With this ground wire connected to the transformer secondary, my source, there is now another return path to the source which has to be dealt with. Also, if lighting hits the transformer, the neutral wire will carry some - a lot - of the current to the main panel where it will find its way to earth through the grounding electrode conductor which must be landed on the neutral bar, not the ground bar.


For residential power poles - It should be noted that the #6 referenced above is also connected to the earth (at the bottom of the pole). All poles have metal earth connections. THIS is why you may have a problem by touching a hot lead while standing on the ground.

If an entire electrical system were never to be grounded, then we could touch individual hot conductors while standing on the ground, without fear. But, we're grounded, so hands off.


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## a7ecorsair (Jun 1, 2010)

Thanks for adding the ground rod. I was typing faster than I was thinking.:whistling2:


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## jlmran (Feb 8, 2010)

Actually I've never seen a rod at a pole. Usually just the wire coiled and attached at the bottom face of the pole, or a plate attached to the bottom face of the pole.


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## vgb88 (Nov 7, 2012)

*Why neutral and EGC are not tied together at qppliance or outlet*

I know this is an old thread, but I thought it was important to add my answer for anyone who might come along and read it. While what you are saying is correct in theory, the whole reason why it's important for the neutral and equipment ground conductors to be isolated at the washing machine is in the case of a wiring error; e.g. say that the washing machine chassis is tied to neutral as in your example. However, what if some homeowner or helpful brother-in-law wired the outlet in reverse? Then instead of neutral going to the chassis in your example, the hot would go there instead. If a barefoot person standing in a puddle of water touched the chassis, then the circuit would be completed to ground through the person's body. It was for this reason that the 3rd ground terminal was added as a clean path to the breaker panel (where it is bonded to the neutral bar) so it could trip the breaker in the event of a short. The distinctive ground terminal greatly reduced the odds that either of the two current carrying wires would ever get accidentally tied to the chassis.



sky jumper said:


> ok so I understand if neutral and ground are connected at an outlet (or device), ground could become a return path for current. my question is so what? since neutral and ground are tied at the service panel, neutral is always at ground potential. this is AC - so it's the hot that varies +/- 170Vpk above and below ground potential, not the neutral. so what if the chassis of the washing machine is tied to neutral? you and the chassis and neutral are all at ground potential anyway, so nothing will happen. your body's resitance is many magnitudes more than a copper wire, so no current will flow through you even if it does flow through the chassis of the washing machine.
> 
> ok now assume there's a fault in the washing machine (or stove top) that shorts "hot" to chassis - it will blow the circuit breaker immediately, even if neutral is tied to hot. no danger there.
> 
> ...


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## Missouri Bound (Apr 9, 2011)

junkcollector said:


> You would have parallel paths back to your main panel; _your ground would be carrying some of the current that your neutral should be carrying_. The ground is normally a non current carrying conductor.


 
Only in the case of a fault. The main panel shares grounds with neutrals.


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