Copper Plumbing Failure Due to Broken Neutral?

True.

But even if the bath is not even grounded as it should be, if you understand how they react to unequal currents on neutral and ground, they will still shut power off within a very short (Milliseconds) of the hair dryer falling in the bath. That is why they are so designed.....

Many countries nowadays have an extra sensitive RCD requirement alone for "wet" areas....that is quite a good idea.....though I myself have just normal ones for the whole house....its something I should do.

GFCI is now (and for many years in the US) required for areas considered potentially wet. These provide a faster circuit trip for shock protection. Certainly improves protection across the whole house, but I've also learned that GFCI plugs tend to trip when there is no problem when connected to things like freezers. Almost lost a freezer full of food because of the "electrical noise" of the freezer cycling and tripping the power to my upright freezer.

That sounds more like the "problem" we are discussing, than a problem of the Freezer/Fridge.....

We have 3 such units, one on each phase, several fridges and freezers, never had a trip.

You could feed the fridge from a separate breaker, but a lot of safety is then removed in that area....

If it could be a problem, then you need a cheap, battery operated freezer alarm....

It may be recommended for "wet" areas, but any area can become "wet" and kill people....

Wait till everything is fixed and try a general RCD for all power, or put in two in parallel.....but think of the innocents in your house!

<...neutral could fail in the main distribution system if it became broken and then shorted to earth such that the return current now flows via the earthed network giving rise to dangerous voltages at various points that otherwise would be near zero....>

Earth and neutral are tied together at the star point of the local distribution transformer anyway!

The householder would not notice this particular fault.

It's across the pond from you, but the tunnels are still open. I can disconnect the temp neutral and you can prove me wrong, but I advise a last will and testament update first ;-)

He is actually right, but assumes that only one "STAR POINT" exists.....as most EEs would.....we all expect a single Star.....wrongly it would appear in some houses!!

All bets are off if more than one.......then it really can be dangerous to life and limb.....

Old German sayings:-

"What does not kill you, hardens you up!"

"What you don't know CAN kill you!"

I have removed one of the 2 OTs you got given, for your excellent technical comment, by some people here who have NO technical knowledge or understanding of what we are discussing.

GA!!!

Well said!

Maybe too complicated for the Dummies?

Surely not, am I saying only an EE would understand it!! That I cannot believe....its really only simple house electrics!!!

PEX was initially the plumbers choice for replacement through the slab, but upon consideration of the expansion and contraction of my clay soil, the potential strain on the connections was determined a greater risk that silver soldering copper pipe connections. They went back with copper pipe for routing under the slab.

What was most interesting to discover was that the degradation of the copper water supply system (and thinning of the copper pipes - I have examples) was isolated to the pipes connected to the single water tank that has the earth ground connected behind the sheet rock. The second water talk (no earth ground), which supplies the other 50% of the house, and lines attached to that tank, have no unusual wear or degradation of wall thickness. I climbed through the whole tunnel system today to inspect the work and just what was replaced, and gathered close to 100 feet of old copper (Still VERY wet and muddy - much like a fox hole in the war). Much of that copper is much too thin and will crush by hand. I have it in my garage so it won't get lost. Had to accomplish that today, as the digging crew is scheduled to begin backfill tomorrow.

As I mentioned previously, all obvious electrical issues now seem to be resolved since the temp neutral was installed by the power company. As one previous post mentioned, a cross connection between a neutral and a ground could exist in an unknown appliance, or in some appliance the ground and neutral could be linked. One doesn't know what one doesn't know.

Interesting post.

With regard to this possibility:-

As I mentioned previously, all obvious electrical issues now seem to be resolved since the temp neutral was installed by the power company. As one previous post mentioned, a cross connection between a neutral and a ground could exist in an unknown appliance, or in some appliance the ground and neutral could be linked. One doesn't know what one doesn't know.

Its quite easy to remove power (phase) and pop the neutral off each circuit and measure the resistance between the neutral and ground. I would expect generally 0.5 MegOhm or higher.

If less than 1 MegOhm, I would split the circuit down and find out why, but if each unit on that leg had better than 1 MegOhm insulation and only when together in parallel it goes under 1 MegOhm, then I would not worry too much....

Local code may have something to say about that!!!

Having more than one Neutral/Ground bonding on any phase can be dangerous under certain circumstances.....

"What was most interesting to discover was that the degradation of the copper water supply system (and thinning of the copper pipes) was isolated to the pipes connected to the single water tank that has the earth ground connected behind the sheet rock. The second water talk (no earth ground), which supplies the other 50% of the house, and lines attached to that tank, have no unusual wear or degradation of wall thickness."

And yet you made no mention of disconnecting that illegal (or at least unwise) connection. I believe code reqires all connections be in a box that can be opened for inspection. If the second water heater was plumbed with copper pipes, then it too would have been grounded. It would have had some deterioration as well.

"all obvious electrical issues now seem to be resolved... One doesn't know what one doesn't know."

Just because the lights don't dim anymore doesn't mean there isn't a problem, and you know about the water pipes grounded behind the sheetrock!

Common practice in this part of the country, especially in the past, to also connect the earth ground of the electrical system to any metal pipes running in the soil and under the slab. Guess it also helps in structure grounding in the event of a lightening strike - lots of lightning and storms in Texas and not too many lightening rods on homes.

The path of least resistance to ground from the water heater inlet pipe (where the copper pipe ground-to-fuse box wire is attached) is within 15 feet of where the first hole in copper developed - at a bend in the hot water supply. All electrical connections are correct, according to local codes.

The second gas water heater has no grounding connection and that path has higher resistance, even though both are connected to the same water input supply.

Apparently the NEC requires the pipes to be grounded. I still think it's a bad idea because it doesn't consider the safety of the plumber or gas pipe technician in a case like yours, especially if he cuts the pipe. In your case with part plastic you may need several ground connections to the remaining copper pipe to meet code. I would consider a flexible conduit from the main panel ground connection back to all the copper pipes, preferably underground, with several connections to it. That way if a pipe gets cut it might still have a ground connection to prevent a shock hazard.

Plastic pipe (PEX) only runs 120 feet from the meter at the street to the front of my home. Copper pipe then takes over under and through the slab. PEX connections are not reliable enough in the moving soil and its mechanical joint stresses to warrant a 25 year guarantee from the plumbing company. City codes require silver solder joints on copper. This has been accomplished and passed city inspection. Now the trenches and tunnels can be filled. All sub-slab copper has been insulated, per code. The point of tying the sub-slab copper to ground was not to improve a structure ground, but to protect lives.

The question remains, though, as to how this protection will take place with plastic pipes. Perhaps through the GFCI plugs - perhaps.

You wrote:-

The question remains, though, as to how this protection will take place with plastic pipes. Perhaps through the GFCI plugs - perhaps.

Does not the sheer amount of information about them, available on the web, not make you tend to feel that they are "perhaps" a good idea? Better than what you had before?

The worries you have about "properly installed" plastic piping, which of course means still earthing anything metal, and NOT thinking that even copper pipes are infallible, because they are not, as your house recently proved to all and sundry....things do happen!

So having "properly installed" plastic piping, with concurrent earthing, should be at least as good, probably far better than it was before! Naturally, BUT a huge leap in safety comes from the usage of GFCI outlets, or breakers.....

GFCI is just another name for RCDs by the way.....

Thought for the day, "If GFCI covered outlets are only 10% safer than without, would you like this 10% to have for you and your family or not?

Only you know the answer.....

I see them as being far far better than that, which is why I don't "play" with the safety of my family and pets, I have had the equivalent in all my houses since the 70's.....all more than actual for the code at the time....even when not a legal requirement!

29 years ago, I bought this house, which then had a relatively small gas tank, for heating and hot water, just behind the garage.

I thought this was dangerous and the smaller deliveries were more expensive per Liter as well.

So I had installed a big gas tank, at the far end of the garden, behind some (actually illegal!) trees, and I insisted that not only was there the standard reducer on the tank, but a second one, near to the house for safety reasons.

The installers carried out the work saying "If you want to waste your money Herr Germany!".

10 or 12 years ago, it became the rule after a series of awful accidents with gas here in Germany, to have two!

The installer who came to install the second one, was TOTALLY blown away when I showed him that I had had two since 1986!!!!

Which by the way, was and is standard still I believe in the UK for many years now for tanks.....but how many people have gas from a pipe under the road or from a cylinder like mine and either have none (that is on pipe deliveries), or just one (on own tanks as I have!) around the world?

Simply put, very unsafe!!! Even though they generally fail closed.....in the middle of winter of course!

I feel this is a somewhat similar situation, you either think safe or you don't!

I have NO idea how many "safety" arguments I have had over the years on CR4, this is just another one for me.....it won't be the last!!! Of that I am really sure!!!

Have a good day.

Good feedback, Andy Germany. Well worth remembering and applying. According to my research, PEX has a 25 year guarantee, but copper has a 50+ year expected lifetime. Copper is also a much cleaner material for antimicrobial action. PEX is less expensive per foot, but the other associated components and tools for connections bump up the installation costs. PEX is hard to beat for above ground installation speed and ease, but each material (PEX Vs Copper) has strengths and weaknesses to consider.

I now have a crew of "miners" working to refill and pack the tunnels. The clay soil mixes well with water, so I will have "adobe" supports under my foundation around the insulated copper pipes. I don't envy the men in the tunnels, but that is their job.

"All sub-slab copper has been insulated, per code."
What a strange code. Now the copper, though bonded, can't improve the earthing of the ground rod but is still just as dangerous to plumbers who cut the line. I wonder what the logic of that was.

In my limited understanding - subject to correction - is that the link of metal plumbing to the earth ground originated before the code requirement for earth ground to all electrical connections (mid 1960 in the U.S.) as a safety measure for wet locations. It was never intended to assist in the earth ground of the house. I've worked on homes built in the 50's where all code wiring was 2-line (power and neutral) with no third ground circuit. In wet area electrical upgrades, clamps were attached to the galvanized water pipes, that ran under the house, to create an earth ground for 3-prong (grounded or GFCI) outlets. This was acceptable code for pre-60's electrical systems "grandfathered-in". I've tested these with the plug-in module that tests for open and reverse connections.

I believe, though, that the grounding rod for plumbing should be separate and isolated from the electrical panel - now for obvious reasons. There is the additional cost - about $25. I believe this even more so, as this would also isolate the natural gas supply lines (connected to the water heater) from also being electrically charged when a neutral breaks. Mine carried the same 88+ volt charge during the past 5+ years, and if there had been any leaks in the natural gas lines, I would not be replying to this post.

"I believe, though, that the grounding rod for plumbing should be separate and isolated from the electrical panel - now for obvious reasons."

Quite clearly incorrect according to the link I provided in #105, which was news to me. You keep saying your installation meets code, while proving you have no idea what the code says. The link has clear pictures that even you can understand. I suggest you read it over carefully. If yours was isolated, your plumber would not have been shocked, but you would not have been meeting code. I suggested a solution to the shocking problem, while meeting code, in #105 also.

Thanks for the reminder, StandardsGuy - I appreciate your inputs! I attempt to absorb 100% from each reply, but sometimes I reach saturation - being human has its limits, no? There are also a lot of distractions inside a fractured home with trades working outside who speak another language, for one person to handle. Even multitasking has its limits, no?

Slide 11 indicates how NEC code indicates which structural elements must be connected to form the grounding electrode system - it is a clear picture for all languages. Still, in the case of a broken neutral return to the power company, a dangerous situation is created when electrical charge is rerouted from design. I've searched and read my local and state codes, to no avail, but I had not read all their reference links, which reference NEC. The list is long for the uninformed in the world of electricity and structures.

I wonder if the new "smart meters" are capable of identifying a broken neutral to a residence? They do provide remote troubleshooting information, but to what extent?

My 8 foot ground rod, within 5 feet of the fuse box, along with the copper plumbing system under the slab, has been struggling for 5+ years to return current to the closest power company transformer (sitting on the ground in an enclosure), supplying multiple nearby houses, but that transformer is at least 200 feet away from my ground rod and plumbing, as the worm crawls. Wonder how that increased "return path" resistance has impacted my electric meter spin? Seems to me like it would have indicated more current usage, no?

Again, thank You to All who have devoted time, resources, and energy to this discussion. I'm gaining some kind of degree from the School of Hard Knocks via the CR4 home schooling network ;-)

If you have a metal bath/shower for example, that needs its own cable bonding to a central earth anyway.

If done properly, the metal piping to and from the bath will be both mechanically and electrically connected to the same earth. Usually with a clamp....

These need to be checked for low ohms within allowed code when installing at least. Code may recommend further checking at certain intervals......

But, as I rant on about, all the time, a correctly installed RCD will STILL protect humans and pets even if the neutral is broken, or simply phase makes contact to ground via a human or anything like that......

This is still the best safety for all concerned AS well as the earth bonding as you just mentioned.....

Why don't you recommend it as well in your posts on the subject of earthing and safety?

I would have to disagree with that.

Most countries use the MEN or some form of the TN system of earthing where the incoming neutral main is connected to earth at the transformer and again at the consumer's main switchboard. The consumer's main earth is connected at that point and to an earthing electrode and any buried water piping.

If there is a lost neutral between the transformer and the main switchboard, then the consumer's earthing conductor would carry the current in its stead. If the earthing circuit has sufficiently low impedance (as it should do), then the consumer could well be unaware of any loss of the neutral conductor.

As there will be some resistance in the earth return circuit, a voltage drop will be evident. Ohms Law will show that if the earth circuit has an impedance of just 2 ohms, then only 45 amps of return current will give you that 88 volts drop. Tests are normally taken via a separate test lead and stake driven apart from the main earth.

Where are you living that allows in local electrical code a double bonding of earth and neutral? Please post the link to such a code, thanks. (Code is always online somewhere....)

I found a reasonable explanation as to why not to do it about E/N bonding here:-

Ground_and_neutral

Where you can read the following:-

Neutral wires are usually connected at a neutral bus within panelboards or switchboards, and are "bonded" to earth ground at either at the electrical service entrance, or at transformers within the system.

Furthermore:-

For larger electrical installations, such as those with polyphase service, the neutral point is usually at the common connection on the secondary side of delta/wye connected transformers.

Normal circuit currents flow only in the neutral, and the protective earth conductor bonds all equipment cases to earth to intercept any leakage current due to insulation failure. The neutral conductor is connected to earth at the building point of supply, but no common path to ground exists for circuit current and the protective conductor.

If double bonded, just as you posted, this can cause severe danger if something "breaks" (as in this case) to people living in such a house....which is why, to the best of my knowledge, it is not allowed.

It appears that in the USA in WW2, to save copper, neutral and ground could be combined in certain fixed wiring only for ovens and the like....butshould hve been corrected long ago.

Maybe this house has wiring that is that old........normally houses (ones my family have lived in) have been rewired probably 2-3 times in the last 70 years..... At least some form of RCD should have been installed!!! Even though code often does not require it......

Thanks for your reply.

I don't believe that MEN systems are allowed in domestic properties for that very reason.....its simply too dangerous....I read something about that yesterday....

Also, we are not talking about such systems either here......BUT, I could easily believe that the OP has multiple Star points, it would explain a lot!!

BUT DO REMEMBER, HE DOES NOT HAVE ANY RCDS EITHER........having one implies the other as well!!!

I suggest you research the above named systems to gain a greater understanding of them.

I would research further (you obviously don't know me) if it was needed for this problem!! Its not, there you are completely mistaken.....

Where are you living that allows in local electrical code a double bonding of earth and neutral? Please post the link to such a code, thanks. (Code is always online somewhere....)

I found a reasonable explanation as to why not to do it about E/N bonding here:-

Ground_and_neutral

Where you can read the following:-

Neutral wires are usually connected at a neutral bus within panelboards or switchboards, and are "bonded" to earth ground at either at the electrical service entrance, or at transformers within the system.

Furthermore:-

For larger electrical installations, such as those with polyphase service, the neutral point is usually at the common connection on the secondary side of delta/wye connected transformers. Other arrangements of polyphase transformers may result in no neutral point, and no neutral conductors.

Normal circuit currents flow only in the neutral, and the protective earth conductor bonds all equipment cases to earth to intercept any leakage current due to insulation failure. The neutral conductor is connected to earth at the building point of supply, but no common path to ground exists for circuit current and the protective conductor.

If double bonded, just as you posted, this can cause severe danger if something "breaks" (as in this case) to people living in such a house....which is why, to the best of my knowledge, it is not allowed.

It appears that in the USA in WW2, to save copper, neutral and ground could be combined in certain fixed wiring only.

Maybe this house has wiring that is that old........normally houses have been rewired probably 2-3 times in the last 70 years.....or should have been. At least some form of RCD should have been installed!!!

Thanks for your reply.

Spades - you have described the situation much better than I. There are three lines supplied by the power company to my fuse box - neutral (white), and two 110 VAC lines (black and red). Those tie in to the 200 A breaker (fuse) box. Inside the breaker box, there is one connection bus for Earth (green) and another for Neutral (white) lines running to each circuit controlled by a breaker. There is an additional 1/8 in diameter gauge wire that runs from the ground strip in the fuse box, out through the wall, and solidly clamps to a metal rod sunk 8 feet into the earth. There is also a second ground rod I installed that is connected to the same line feed going back to the fuse box earth bus.

Just evaluated my Siemens 200A breaker box. Ground bus in the left side, Neutral bus on the right. 3: 600V 1/0 lines feeding the breaker panel. I discovered that the neutral bus is mechanically connected (by design) to the frame of the fuse box, as is the earth ground. Design for this breaker box is for both the neutral bus and the earth ground to be in common.

Now I know how the return path to the power company (neutral line) was redirected to my earth ground - inside the fuse box.

"Now I know how the return path to the power company (neutral line) was redirected to my earth ground - inside the fuse box."

You would have known a lot sooner if you had read my posts (and a few others).

As the OP, I'm reading and evaluating each comment and learning. This situation has changed my life and home (over $100,000 in damage), but sometimes I have to turn off the computer.

I understand. I feel for you and think it's a shame that your insurance company can't come through for you. That's why I'm trying to help you to fix the present problem(s) instead of distractiong you with upgrades that are not the problem. Good luck.

Good question, PW. My training is measuring TO earth ground for potential voltage, so I'm unsure how the power company tech arrived at that value, but he did. He replaced my "plug in" energy meter with a second test unit that had places for DVM probes. It was then that he determined the charge on what should have been zero. Since there was no neutral connection for a return path to the transformer, my earth ground (8 foot metal rod into the ground, connected back to the fuse box earth ground strip, about 5 feet away) was sending the home return voltage into my grounding system instead of the neutral line. Now that I have a temporary neutral, and that is functioning properly, I have no more blinking or dimming lights and no change in electric motor hum when I operate appliances (like a microwave oven or a coffee pot).

Who is the comedian posting 'Off Topic' to perfectly valid replies.

Ignore it.

I hope you are not "Patty" , who I worked with at Intel I.Q. n Albuquerque, NM. His last name was Slack and we are friends ;-) You in Ireland?

No clues here - I did not notice. Of course, I'm still in the middle of this hell and doing my best to survive. None of this is history - it is NOW.

Mark

It is incorrect to rely on the copper in water pipes as forming a valid earth electrode, simply because so much of the water distribution network is plastic nowadays. Such a practice falls outside British Standard 7671, and a professional installer encountering this problem is duty-bound to correct it, on safety grounds. Therefore, in a correctly-installed and maintained system, there is no threat to the copper in the water pipe. A greater threat would be presented to the individual using the water in the pipe.

I'm thankful that the neutral was corrected last Tuesday. On Thursday, before dawn, a temporary rubber boot (used on a pressure line) broke and I found over an inch of water covering the entire floor. Discovered later that day that a power strip (still plugged in), which was on the floor, had melted when it became too wet. Thank God it stopped functioning after it melted and isolated the live wires inside. I walked through the water several times before discovering I could have been electrocuted.

As I have mentioned several times here and I believe others also have mentioned, adding RCDs or what ever they are called where you live (don't make the mistake that I believe Horace40 is making in assuming that they react only to current THROUGH them. An RCD react to when the power in the phase is not exactly the same as that through the neutral), which would in the various circumstances you describe / have described, have dropped the power within a few milliseconds and probably prevented it being restored completely till all failures were found and fixed!!!

Also, the first drop of water in that power strip would have dropped power to it and the strip would not have melted!!! But it would have needed drying out!! But no damage or risk of fire. Yes even a few drops of water can melt things, as you saw, and if the water then stops/Boiled off, the melted parts can catch fire!!

If the mains is/was properly grounded as I suspect, then through the power strip was grounded via the water and a concrete(?) floor, which was why high currents were flowing that melted the strip.....

What would be a good idea (only done in UK homes as far as I am aware with the "Ring Mains" in houses and old RN DC Aircraft carriers too!), is to split the mains supply in the house, putting an RCD in for each leg, but spreading the legs so that lighting and power are available in each area from at least two different sources (correctly marked of course), so that you do not lose all power and light in any room.....a bit of planning needed!!

If your house ground had been bad and the substation ground a long way off or very "dry" ground, e.g.high resistance, then you may have then experienced a shock.....

This shows just how important a good grounding is for everything!!

Power strip was sitting in an inch of water. Ground outside has gotten so dry there are 1 inch wide cracks in the yard. The power strip had my blood pressure monitor plugged in and the prongs of that plug are very discolored and corroded. Fortunately, it still works because it was not turned on.

What is your take on installing an RCD?

I'll have to investigate further. Have GFCI all over the house in bathrooms, kitchen, etc., but have also had to swap one in the garage with a standard 3-prong 15 A outlet due to the GFCI shutting down (tripping) when my small food freezer cycled. Not good when a GFCI turns off your food freezer or fridge. Seems like I've read that just about anything with a motor creates spikes that can trip GFCI.

You have probably bought a sensitive RCD that should protect humans in Bathrooms and the like.

Or the quality is not as good as it should be.

Or the fridge motor is starting to show its age.

Maybe fridge insulation is already under par.....has it been tested with a Megger or high voltage equivalent? (You need an electrician for that generally) As a normal Ohm Meter is simply not the right test equipment.....BUT if the simple Ohm Meter shows less than 1 MegOhm to frame ground, the fridge insulation is definitely rubbish and the RCD is simply pointing this out!!!

What does the Electrical code give you as for a least sensitive RCD allowed for domestic buildings? Go for that.....

But remember, your RCD may be simply trying to tell you something that you don't know.....

The only times I have seen such problems with RCDs (actually it was an ELCB then if I remember correctly), was when I had a kettle with a slightly porous element and so did a neighbor on the same transformer.....(I don't remember now if we were on the same phase or not anymore)

It took me ages to pin down as I did not own a Megger at the time (still don't!!).....70's in the UK......it was quite irrational as to when and how till I replaced my kettle element and his......

I don't remember the fine details, but we were talking (good friends) and he mentioned that sometimes his ELCB dropped for the whole house, the same as mine did.

On comparing notes, mine was going off at the same moment!!!

On comparing further, we noted wives boiling water.......

I do remember that BOTH kettles had to be switched on at the same time for the problem to happen......I took my element to work and it was well under 1 megohm insulation.....thats all I remember.....his I did not even test as he simply bought a new kettle (rich Guy!).

Problems solved!!

I remember I tripped a 30 ma version probably at least 15 - 20 years ago when teaching a class at my work. Its still painful even with an RCD I can tell you and I have had many shocks over many years, so I do know what I am talking about.

I have experienced both DC 220 VDC (many times) and even NATO RN 440 VAC 3 phase (once)!!!! That really stops your brain for several seconds. It went via both hands, both arms, down through my body and out via sweaty backside/overalls into a steel pipe I was sitting on!!!

None of this is much fun.....although 220 VDC, is not really a problem, though many text book writers on electricity, who have never ever experienced even ONE shock, believe it is!! They write a lot of twaddle, copied from another with even less experience that they have.....

AC is FAR more painful for an equivalent voltage, partly due of course to the RMS values shown on a voltmeter not being the maximum voltage experienced on AC.... As any EE will understand....

Which means that 220 VAC has a peak value of over 310 volts!!

NATO 440 VAC has a peak of around 620 VAC!!!

A simple explanation for this can be found here if anyone is interested:-

http://www.n9xh.org/license/pcara_general_upgrade_lesson_07.pdf

Thanks for the information, Andy Germany! I will study further. The freezer was about the least expensive I could find but it has served me well, over 20 years.

Get it tested....

I agree with your comments completely.

But even if there was acid ground, or water supply, it would not "SUDDENLY" one day, "SEPARATE" a copper pipe.

It would start with pin holes in strange places like bends and badly soldered joints, WELL BEFORE it separated!! Months if not years!! There would be enough forewarning.....

Someone cut/removed the copper pipe and "discovered" the wiring error!!

There was some awful off code wiring as well here, some one using water pipes as neutral or ground return for a device using mains power....

As a bonding point for "un-powered" metal objects like sinks, maybe! I don't know the local code.....

But if pushed I might do that here if:-

a) it saved me from a really difficult earth wiring run

b) I tested the connection first for as good as zero Ohms connection to the house ground.

c) I had RCDs or similar in place for each and every phase (we have 3 phase power here in a house!!) - just in case!

C D Light,

I suggest that you PM JRaef and ask for his opinion on your problem.

In my opinion he is the undisputed authority on this forum in the field of electricity.

No member will dispute that he is, without a doubt, someone who knows the answer to your plight.

I'm surprised he has not offered his help.

In most areas of the USA the electrical system ground is bonded to the building plumbing therefore if the neutral in a Wye grounded system opens between the source and the building the plumbing and soil become the neutral current return to the transformer.

This means the plumbing which in this case is copper and the soil between the transformer and the home/building becomes energized which will definitely increase corrosion of the copper pipes due to current exiting the copper pipe into the earth/soil. The wetter the soil the faster the corrosion occurs.

This is a common occurrence issue when the neutral is severed between the building and the source where the ground is bonded to the plumbing.

My neighbor went through this a few years back and ended up having to replace all of the copper plumbing below grade which required saw cutting of all his concrete floors throughout his home where the plumbing was routed.

A very costly and very trying 2 month ordeal.

Exactly the issue here. And it has been a costly 2 month ordeal with all the above. That does not include ruining about 1500 sq ft of wood floor and carpet and the illness created by wet carpet.

NEC (pot 105, I believe) requires all metal under the slab to be grounded back to the fuse box, where neutral is bonded to the box, also.

Do you know if there was any compensation from the power company for the loss and expense?

Yes there was some compensation arranged but it had to take place legally because the utility company would not willingly accept the liability nor the associated cost.

Often the homeowner's insurance company will assist in pressing the issue for just compensation.

This is one of those cases wherein the "dreaded" lawyers are usually required because honesty and accountability are pretty much lost in today's society.

Thanks, Shockiscan. I've already begun homework there and found an interesting paper written by Dr. Ronald B. Standler - both an EE and a Lawyer, for Legal Liability for Electricity in the USA: Product Liability.

http://www.rbs2.com/utility.pdf

I've already communicated with Dr. Standler and gotten his permission to share his research. Now to find the correct legal representation.

YAW. Take no prisoners! I guarantee if the costs were caused by you or your personal equipment to the utility company they would pursue legal action against you to the Nth degree without conscience.

Another reference article for

How Loss of the Neutral Connection in a Sub Panel Led to a Dangerous Electrical Shock

http://inspectapedia.com/electric/Electrical_Neutral_Lost.php

Guess this pretty well closes the discussion. The broken neutral issue is both known and documented (including the power company). Metal breakdown, caused by an extended period of electrical charge on plumbing (both water and natural gas piping) under and through a slab, is understood, and works at different rates, according to the voltage, local water and soil pH. Electrically connecting all these building and electrical systems together seems to be a requirement by the NEC, at least in Texas.

Is there a safety backup for people in addition to installing both ground fault and neutral fault equipment before the main breaker? Seems to me like some unknown personal safety issues may have developed since the NEC requirements became the norm.