Floating Neutral

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sdv

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Please comment?

My house experienced light flickering and several electronic components failed, including the washing machine w/ electronic controls. The cause was a floating neutral (240/120 VAC single phase service). The utility's neutral conductor came loose from the meter base neutral terminal connector, which left the house neutral floating. This in turn created a voltage divider affect on the 120 VAC loads. The greater the imbalance of the on-line 120 V loads, the greater the voltage on the 120 VAC loads up to 240 VAC. The utility confirmed in writing that this is what occurred.

I made a claim with the utility and was denied. They (the claims agent) stated that if my ground rod at the home was properly grounded then this couldn?t happen. I disagree. If the transformer is properly grounded, and the home is properly grounded, then you still need current flow from the home?s neutral to ground through the ground rod, through earth, and back to the transformer. The pole mounted service transformer is approximately 100 feet away, so that?s still a relatively high resistance current path. A properly grounded (low resistance) ground rod only insures that the neutral stays at zero volts. If there is a good ground path back to the transformer, it could minimize the voltage divider affect by allowing current to flow through the neutral of the transformer...but no guarantees.

He also said that the electrician measured from each phase to ground rod and read 120 VAC with no loads connected, which somehow means there service was good.

Does anyone have experience with this issue?
 

roger

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Fl
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Retired Electrician
SDV, welcome to the forums.

Regarding your thread, I feel I must mention the forum rules.

Rules, Policies, and Disclaimers

No information gathered from this web site shall be treated as being the opinion of an 'expert witness, and you do not have anyone's permission to present such information as evidence in any type of legal dispute.


With that said, the GE would not have helped in this situation and I would have expected the response you got from your POCO.

Roger
 

realolman

Senior Member
I am no expert witness. Just ask anybody in this forum.

I think that the ground rod at your service being connected or not connected would have no effect on the voltage from either phase to neutral.
 

haskindm

Senior Member
Location
Maryland
The presence or absence of the ground rod and the ground rod's resistance to earth would have almost no effect on a lost neutral on a residential wiring system. My advice (for what it is worth) is to turn it in to your home-owner's insurance carrier. Let them fight with the POCO. They have much better lawyers than you can afford! The NEC specifically states that the earth is NOT to be used as a return path, and that is what the POCO is telling you it should do. They are blowing smoke and hoping that you will go away.
 

e57

Senior Member
I had a long detailed response and it vanished in spell check... :mad:

Who owns the equipment the neutral was lost in - you or them?

Most metering and conductors to and from them are customer owned and maintained. Even though their meter is on/in it.
 
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brian john

Senior Member
Location
Leesburg, VA
Assuming you are relating this properly:

1. It was not a floating neutral it was an open neutral.
2. You need to know where this open occurred.
3. If you had an electrician, it sounds like his expierence was not in this end of the field.
4. The utility appears to be off base also.

And the rest of the comments above. Hate to say it but that is why you have homeowners insurance.
 

dereckbc

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Location
Plano, TX
SDV, ground has no effect on this problem. You could lift the ground at the transformer and your service, and the system would work normally with no noticable ill effects. Technically speaking ground is not needed, its purpose is for life safety, not for normal operation.

You need to contact your insurance agent, file a claim, and inform him/here your service nuetral opened. They know exactly what this means and what it causes.

The only problem is who was responsible for the cable where the open occured. You insurance carrier will get to the bottom of it. If you owned it you rcarrier will have to pay minus your deduction. If the utility ownes it, then they get to caugh up the money.
 
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dereckbc

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Location
Plano, TX
sdv said:
He also said that the electrician measured from each phase to ground rod and read 120 VAC with no loads connected, which somehow means there service was good. ?
Of course with no load current it looks good. It is only when load current flows the imbalance shows up. It also depends on where you measure at. If at the transformer or ahead of the open nuetral circuit, it will always read balanced regardless of the load current. The key here is whoever took the readings was not qualified or not serving your interest. Anyone who knows the trade would know there has to be load current for the imbalance to show up.
 

e57

Senior Member
sdv said:
If the transformer is properly grounded, and the home is properly grounded, then you still need current flow from the home?s neutral to ground through the ground rod, through earth, and back to the transformer. A misconception.... The soil conditions can change from day to day, and there would be no way to predict or depend on the earth as a return conductor. ~ Well unless both rods are in a continuous vain of solid gold... :grin:

A properly grounded (low resistance) ground rod only insures that the neutral stays at zero volts. More apt analogy is like it brings the earth around the rod to a closer potential to the neutral - reducing the potential difference, and subsequent shock hazard of exposed metal parts located near the electrode. As well as providing a path to (Or from) ground for lightning and dissapating it over a broad area via the grounded neutral to various grounded locations connected to that transformer.

Either way, consider yourself lucky - it didn't kill anyone by setting your coffee machine or some other appliance on fire and burning down your home. IMPO this is one of the top 5 reasons for electrical related fires - closer to #5 than say EGC or OCP failure during short circuits.

Anyway - You may want to invest in some Arc Fault breakers - They do ABSOLUTLY NOTHING in relation to lost neutral (High/low voltage) events - But in the last few lost neutrals calls I have been to - they failed open... IMO slightly reducing the exposure to things on them - just my opinion....
 

iaov

Senior Member
Location
Rhinelander WI
Just a quick note. I agree with what everyone has said so far. One thing they haven't mentioned is that the neutral wire coming from the POCO goes to the center tap of the transformer. Lose this neutral and it all turns into a 240 volt series circuit at your panel. Ground has nothing to do with this.
 
What the power company is telling you is the truth. If you had a good grounding electrode, water main or a good ground rod you would have never known there was a problem. I have seen this before, I saw the exact thing when I changed a service at a house. When I pulled the meter to kill the power to the house the nuetral lugs were totally disconnected. The house was working as normal on the water main ground.
 

iaov

Senior Member
Location
Rhinelander WI
That water main ground is still going back to the center tap however it may going through someone elses neutral bus. A dangeous situation.
 

haskindm

Senior Member
Location
Maryland
sparkygriffin said:
What the power company is telling you is the truth. If you had a good grounding electrode, water main or a good ground rod you would have never known there was a problem. I have seen this before, I saw the exact thing when I changed a service at a house. When I pulled the meter to kill the power to the house the nuetral lugs were totally disconnected. The house was working as normal on the water main ground.
The power company is NOT telling the truth. They are using the ignorance about the purpose of "grounding" in order to deny responsibilty.
What you probably experienced is two houses, fed from the same transformer, that were both "grounded" using a common waterline. When the neutral to one house was broken the neutral currents traveled on the waterline to the other house where they returned to the transformer via the ground/neutral connection on the neighbor's service. While this masked the problem, it created a potentialy dangerous situation. The grounding electrode (waterline) became a current carrying conductor for the neutral current. This is not a good situation. This possible parallel path for neutral currents is a flaw in our present power distribution system. I don't know how to fix it, but it appears to be a growing problem.
 
I never said it was a good situation I said that if his house was properly grounded he would not have known about the problem. That I believe was his question. And what the power company said.
 

Mike03a3

Senior Member
Location
Virginia
e57 said:
Anyway - You may want to invest in some Arc Fault breakers - They do ABSOLUTLY NOTHING in relation to lost neutral (High/low voltage) events - But in the last few lost neutrals calls I have been to - they failed open... IMO slightly reducing the exposure to things on them - just my opinion....

If that's the normal case, that may be the best justification for residential AFCI's I've heard.
 

roger

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Location
Fl
Occupation
Retired Electrician
sparkygriffin said:
What the power company is telling you is the truth.
No it is not the truth, especially if the GES only consisted of only Rods.

sparkygriffin said:
If you had a good grounding electrode, water main or a good ground rod you would have never known there was a problem.
If the metallic water pipe was common to other houses and back to a common transformer this could work but it poses other dangers as well, if it was a rod it would be next to impossible to complete the service back to the source, there would have to extrememly high levels of metals and salts in the soil.

sparkygriffin said:
I have seen this before, I saw the exact thing when I changed a service at a house. When I pulled the meter to kill the power to the house the nuetral lugs were totally disconnected. The house was working as normal on the water main ground.

Out of curiosity, was this in a city with a common water system?

Roger
 

brian john

Senior Member
Location
Leesburg, VA
I never said it was a good situation I said that if his house was properly grounded he would not have known about the problem. That I believe was his question. And what the power company said.

Actually if the house was properly grounded, and you lose the neutral (grounded conductor) connection at the utility transformer, meter can or in the panel for that matter, you would have the exact same anomaly that occurred in the original post. Now if there are some alternative paths or incredibly low earth resistance, who knows?
 

e57

Senior Member
Mike03a3 said:
If that's the normal case, that may be the best justification for residential AFCI's I've heard.

Not sure it is always the case - but the last few have been. They are of course toast after this.... :grin: GFIs too.... Since they are letting the smoke out - I imagine a number of, or whole panel full of them may be just as bad as letting the smoke out of a few appliances - depending on what they are..... :wink: $20-30 each can add up in a panel... IMO if they made main breakers to specifically trip for high/low voltage - I would sell them on every job!

iaov said:
That water main ground is still going back to the center tap however it may going through someone else's neutral bus. A dangerous situation.

A while back I had one like that - my customer blamed the neighbors plumber for the electrical demise of his stuff - I had to explain that it was not his fault, and the replacement of the neighbors water main had nothing to do with it.
 
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