Will water bond carry neutral load and balance legs with lost neutral?

[Epalmateer]

I used to check for a bad utility neutral by pulling the meter, hooking up a temp with a small air compressor attached to one leg and neutral and checking voltage under load. Now that i can't pull the meter here I can't do that. I was at a job where I suspected a bad utility neutral so I checked voltage under different loads and everything checked out. Later that night one of his surge strips caught fire, and Poco determined it was bad neutral underground. Would the water bond carry neutral load and balance legs, leading me to believe neutral was fine? If I were to turn off the main, disconnect the neutral in the panel, hook up temp on line side of main breaker with a load, and test voltage between that leg and the disconnected neutral, would it have shown an imbalance?

 

[tom baker]

The water line could carry the unbalanced current if it was continuous to the water main and then to another house

 

[infinity]

If the GEC connection to a water pipe electrode was good and you had a city water system then a lost utility neutral might go completely unnoticed.

 

[augie47]

If the GEC connection to a water pipe electrode was good and you had a city water system then a lost utility neutral might go completely unnoticed.

Until a person working on the plumbing cuts or some way separates the supply side metallic piping Then the "plumber" knows quickly

 

[ptonsparky]

You did not have a large enough test load. Hair blow dryers or portable Milk House heaters work well and it would not matter where the load was placed. Voltage at the SE would have changed enough to call the POCO.

 

[Epalmateer]

If the GEC connection to a water pipe electrode was good and you had a city water system then a lost utility neutral might go completely unnotic

You did not have a large enough test load. Hair blow dryers or portable Milk House heaters work well and it would not matter where the load was placed. Voltage at the SE would have changed enough to call the POCO.

I used a table saw that customer had in basement

 

[Epalmateer]

You did not have a large enough test load. Hair blow dryers or portable Milk House heaters work well and it would not matter where the load was placed. Voltage at the SE would have changed enough to call the POCO.

You did not have a large enough test load. Hair blow dryers or portable Milk House heaters work well and it would not matter where the load was placed. Voltage at the SE would have changed enough to call the POCO.

No, I used the air compressor, so you are probabsly right about the load not being big enough.

 

[ptonsparky]

A disadvantage of using the customers items to test with is you have a possibility of damaging them. Prior to the modern power supplies that can take a wide range of voltages, bad neutrals were often evident by the smoke that would escape from various appliances.

 

[gadfly56]

No, I used the air compressor, so you are probabsly right about the load not being big enough.

Table saw or air compressor? In either case unless the table saw is making its way through a 6x6 or the air compressor is cranking up to 150psi or so, neither one will be operating at full load.

 

[Epalmateer]

Table saw or air compressor? In either case unless the table saw is making its way through a 6x6 or the air compressor is cranking up to 150psi or so, neither one will be operating at full load.

I used the little air compressor, so your probabsly right about the laod not being large enough.

 

[EJPHI]

Seems like a great application for a clamp on current probe. If most of the neutral current shows up on the GEC, well there you go.

 

[Hv&Lv]

I use a hairdryer, an actual heat gun, or a “beast”.
depending on where I test.
one thing before you call the poco.
make sure it’s not a bad neutral in the SE cable.
I have had calls on these where the electrician said our neutral was bad only to find a bad SE cable either from the Meterbase to the main or from the Meterbase up to the weatherhead.
a small air compressor load may run with the neutral connected to the ground rod…
You definitely need a bigger load and I would suggest a cheap high wattage cheap hairdryer rather than a customer owned item.

 

[Another C10]

hook up temp on line side of main breaker with a load, and test voltage between that leg and the disconnected neutral, would it have shown an imbalance?

This seems to me to be pretty involved not to mention putting yourself in a position of a lot of potential liability, I agree with EJPHI above, clamp on an amp probe. or completely disconnect the main utility feeds and its neutral, testing only the load sides of the distribution loads. I've also had to wait many minutes to see a significant fluctuation of amperage during a high load application to help indicate the presence of an arcing bleeding condition.

Technically the way we land the neutral at the main with adding electrodes and water-gas bonds to the same utility neutral reference, there is no question that a return current can easily find another route to complete the necessary circuit/s. Obviously that route would be a safety problem.

 

[Russs57]

Had a guy at work ask me why the rainwater was boiling/steaming under his meter.

 

[roger]

Here is an illustration showing how an underground metallic water system can not only carry the neutral current of a single service but multiple homes if there is a broken neutral.



Roger

 

[tom baker]

Technically the way we land the neutral at the main with adding electrodes and water-gas bonds to the same utility neutral reference, there is no question that a return current can easily find another route to complete the necessary circuit/s. Obviously that route would be a safety problem.

Gas lines will not carry neutral current due to insulating union at meter.
Ground rods even at 25 ohms will only carry a few amps

 

[don_resqcapt19]

This seems to me to be pretty involved not to mention putting yourself in a position of a lot of potential liability, I agree with EJPHI above, clamp on an amp probe. or completely disconnect the main utility feeds and its neutral, testing only the load sides of the distribution loads. I've also had to wait many minutes to see a significant fluctuation of amperage during a high load application to help indicate the presence of an arcing bleeding condition.

Technically the way we land the neutral at the main with adding electrodes and water-gas bonds to the same utility neutral reference, there is no question that a return current can easily find another route to complete the necessary circuit/s. Obviously that route would be a safety problem.

If the path via the metal underground water pipe system a safety problem, why does the NEC require us to create that "safety problem"?

 

[texie]

As shown in Rogers diagram, an open neutral can go undetected for decades. Older communities with all metallic water systems. Had one like this a few years ago that was discovered when the plumber cut the main line to a house to replace a valve. Found the neutral had never been connected at a POCO splice pedestal some decades prior and went completely unnoticed for all those years.

 

[Another C10]

If the path via the metal underground water pipe system a safety problem, why does the NEC require us to create that "safety problem"?

The connecting of the water-gas or structure to the (line neutral) of the utility supply is to protect those systems within the structure from stray voltages originated from the distribution branches , not to allow for a secondary path incase the original utility (neutral) fails. In addition the electrodes purpose are primarily for lighting strikes coming down the utility line so that the inrush can disburse into the earth rather than throughout the various metallic systems of the facility

 

[don_resqcapt19]

The connecting of the water-gas or structure to the (line neutral) of the utility supply is to protect those systems within the structure from stray voltages originated from the distribution branches , not to allow for a secondary path incase the original utility (neutral) fails. In addition the electrodes purpose are primarily for lighting strikes coming down the utility line so that the inrush can disburse into the earth rather than throughout the various metallic systems of the facility

There are two separate requirements for connections to metal water pipes. the one you mentioned and the requirement to use the metal under ground water pipe as a grounding electrode.

It doesn't matter why you are required to connect the metal underground water pipe to the electrical system, the fact is that where there is a common metal underground water pipe in the area, a substantial portion of the grounded conductor current will flow on the water piping system even where there are no problems with the service neutral. It is a physical metal parallel path via the other grounding electrode conductors connected to that water pipe system for the grounded conductor.

If using the water pipe as a parallel path for the grounded conductor is a safety hazard why does the code require that we create that parallel path. That path could be eliminated by the use of an insulating fitting between the interior metal water piping system and the underground water piping system. The gas utilities have been doing that for a long time to prevent their metal underground gas piping system from becoming a parallel pat for the service neutral.