Neutral connected to ground wire

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hardworker

Senior Member
On a job, I found a bathroom ventilation fan was powered by jumping the black wire (hot) from the light switch and the white (neutral) was connected to the green ground wire of the light switch. There was no neutral in the immediate area, so they tied it to the ground.

What does this do to the integrity of a sub-panel system? I know it is against code, but what problems does it cause.

I removed it and wired it properly.
 

Dennis Alwon

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Chapel Hill, NC
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For one there would be current travelling thru all the grounds in the system. The egc only carries current during fault not normal operation.
 

augie47

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State Electrical Inspector (Retired)
hardworker, picture the ground becoming disconnected at the panel.
The voltage flowiing thru the fan from the "hot" wire would then be present on everything connected to that "ground".
 

hardworker

Senior Member
Correct me if I understand incorrectly. All breakers would still work correctly. The problem is the voltage being put into the grounding system. The fan is a small fraction of an amp, so the problem is minimal, but not good.
 

roger

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Fl
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Correct me if I understand incorrectly. All breakers would still work correctly. The problem is the voltage being put into the grounding system. The fan is a small fraction of an amp, so the problem is minimal, but not good.

The problem would not be minimal, it is potentially deadly, see post #4 and I would add that it's not just the possibility of the EGC coming loose at the panel, it would be anywhere the EGC could be broken.

Roger
 
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Cold Fusion

Senior Member
Location
way north
On a job, I found a bathroom ventilation fan was powered by jumping the black wire (hot) from the light switch and the white (neutral) was connected to the green ground wire of the light switch. There was no neutral in the immediate area, so they tied it to the ground.

What does this do to the integrity of a sub-panel system? I know it is against code, but what problems does it cause. ....
I don't know. Compared to some other similar practices allowed by the code, it doesn't look much different to me.

For fifty years it was okay to use the neutral for the ground on dryers and stoves.

The neutral and ground are the same wire on the utility side of your meter.

The utility deliberately grounds their neutral in multiple locations. We can even do that on our side of the meter for some installations.

For at least one case, the NEC demands we put neutral current over a metalic ground path. (Industrial application where there is a ground mat connecting the padmount transformer case and building steel)

The code allows a grounding conductor to be used as a neutral for dimmers, fan controllere, and occupancy sensors.

There is no body count from these practices - except for maybe the utility MGN practice.

I certainly would not recommend using a grounding conductor for a current carrying conductor. But I also wouldn't recommend several common wiring practice that are acceptable to the NEC.

cf
 

Teaspoon

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Location
Camden,Tn.
The problem would not be minimal, it is potentially deadly, see post #4 and I would add that it's not just the possibility of the EGC coming loose at the panel, it would be anywhere the EGC could be broken.

Roger

Ran into a problem like that,a couple of weeks ago.I was doing prep work for a change-out. Had a 40 amp D.P. breaker labled as Carport Light.
Sure Enough it was The porch Light. Somebody had used 1 hot leg and the bare copperground for Neutral. I also found out they were running 2 A/C's
On A 30 amp circuit.Both A/C's required a 20amp circuit.Homeowner said the breaker had been tripping alot. Some people must really work hard to come up with some of these idea's.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
For fifty years it was okay to use the neutral for the ground on dryers and stoves.
It was, and a customer of mine was hurt badly when the neutral wire of the range cord pulled out of its crimped lug in the terminal compartment. For a month or so, the range clock and lights had stopped, and it took that long for him to touch the range and sink simultaneously.

The neutral and ground are the same wire on the utility side of your meter.
They are, and we know all too well what happens to 120v equipment and appliances when the service neutral opens. What few notice is that the house plumbing and GEC systems are energized, until someone starts a 'hose bib shocking' or 'plumbing fixtures shocking' thread.

The utility deliberately grounds their neutral in multiple locations. We can even do that on our side of the meter for some installations.
They do, and, we can, but, the practice of grounding a supply conductor is also the practice that assures that the other conductors have a fixed voltage to earth, and a (relatively) low impedance back to the source. GFCI's don't work on ungrounded systems, nor are they needed.

For at least one case, the NEC demands we put neutral current over a metalic ground path. (Industrial application where there is a ground mat connecting the padmount transformer case and building steel)
I guess they do, and the MGN actually assures that the earth itself carries some primary neutral currents. Fortunately, there is little step-potential hazard due to the prolificity :)roll:) of electrodes. I'll still take the predictability of a grounded supply over a non-grounded one.

The code allows a grounding conductor to be used as a neutral for dimmers, fan controllere, and occupancy sensors.
It does? :confused: I understand that some UL-approved electronic devices depend on the availability of an EGC when there's no neutral, but I wouldn't call that 'neutral current.' It's more of a reference, but no load current uses that path. I don't think the code 'permits' that, though.

There is no body count from these practices - except for maybe the utility MGN practice.
That one, I don't get. Since I have nothing to add here, I'll take this opportunity to mention that I'm not picking on you, just having fun bringing up the other side of the argument. I also like making each paragraph the same size, so I'll keep typing until I get to the end of this line.

I certainly would not recommend using a grounding conductor for a current carrying conductor. But I also wouldn't recommend several common wiring practice that are acceptable to the NEC.
No argument there. :)
 
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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Is that how one gets shocked touching the sink?
It can be. Remember, a voltage is measured between two points. The range is more likely to become energized than the sink, but stranger things have happened.

It would be hard for the plumbing to become energized and not the service neutral. The range can be a source of electrical energy; the sink is more of, well, a sink. :cool:

It doesn't matter which point is hot and which is (or is supposed to be) grounded to the one getting shocked, but it does to the electrician working on the problem.
 

Cold Fusion

Senior Member
Location
way north
...I certainly would not recommend using a grounding conductor for a current carrying conductor. ...

...No argument there. :)
I have noticed that comments (other conversations as well as this one) describing the dangers of using the grounding/bonding conductor for a neutral, tend to focus on two aspects:
1. The practice is dangerous if the system is somehow broken/damaged/improperly installed. Yes that is true - It's also true for most any other system as well.

2. The practice is dangerous because the code says it's illegal. Ah - yes. Tis dangerous when we violate the edicts of the Wisemen of Gotham:roll:

cf
 

iwire

Moderator
Staff member
Location
Massachusetts
2. The practice is dangerous because the code says it's illegal. Ah - yes. Tis dangerous when we violate the edicts of the Wisemen of Gotham:roll:

cf

cf, come on, you are not really going to argue that running an EGC is not better that using the neutral?

For years we had live front gear and I bet people complained about the added cost and trouble of dead front gear as well when that was required.

BTW, the wisemen will consider proposals from wise engineers if they send them. :grin:
 

Cold Fusion

Senior Member
Location
way north
...BTW, the wisemen will consider proposals from wise engineers if they send them.
First I want to be clear that I am not a distribution whiz. My thoughts are based on research and experience with industrial off-grid power generation systems (400KW - 20MW range)

So, from that point of view:

The US and most anywhere touched by the US uses TN-C (MGN, and common NG on our side of the service transformer). I think because it is one of the cheaper methods, and safe enough the body count is not high enough to start a public outcry - probably because of the money it would take to change it.

Other places (a lot of Europe) use TT, Norway uses IT.
Both appear to be safer and more reliable.

For my house, I'm pretty well stuck. Unless I'm interested in self-generation, I have to deal with the issues of MGN distribution. That is the LAW (nec) And I tend to follow the law.

My clients are mostly self-generation, or take the utility service at the primary. This allows Impedance Earthed TN-S, or IT And that alleviates most of the NEC/NESC oddities.

So, the issues go way deeper than can be solved by a few proposals. This whole idea of utility MGN and using the neutral and grounding bonding conductor on our side of the service is a poor idea. Too bad, that is what we got - I deal with it.

Here is a link discussing the different systems. If you are having trouble sleeping - it is excellent.

http://www.schneider-electric.com/d...ility-safety/low-voltage-minus-1kv/ect173.pdf


cf
 

hardworker

Senior Member
Please clairfy for my understanding the difference between using the ground for the neutral, as discussed in this post, as opposed to the grounds and neutrals being connected together in a main panel?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Please clairfy for my understanding the difference between using the ground for the neutral, as discussed in this post, as opposed to the grounds and neutrals being connected together in a main panel?
The difference is that the EGC system is tied to the neutral in the main-disconnect enclosure. That's really where the EGC system originates. In order to function, the EGC must be tied to the supply neutral.

Using an EGC downstream of that point as a CCC increases the likelihood of energizing surfaces that should be grounded. Even without a break, simple voltage-drop causes some voltage 'above' earth.

We treat grounded conductors the same a hot, as far as insulation and isolation from ground is concerned, for just that reason. We cannot safely regard the load end of a CCC to be the same as the supply end.

In other words (except for moments during ground faults), we can (or should be able to) expect EGC's and bonded surfaces to be at zero volts to earth, but cannot expect the same of grounded conductors.
 
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