Need Help With A Shocking Outside Waterspout

Badoish

I was on a service call today for someone that had a metal outdoor waterspout that shocked when touched. It's all copper pipe inside and I grounded every pipe back to the panel but it's still shocking. The spout does leak when you turn it on and wets the ground. Anyone else have an idea what it may be?

Rich R

Sounds like it could be a loose or open Neutral at the service. The service might be using the water system as a return instead. I would definitely take a close look at the service equipment and make sure everything looks right

Magnettica

I think that's exactly what it is. EC&M magazine had a great article on this subject awhile back. I'll try to find it and link it for you.

By the way, check the neigbors hose bib too. I'll betcha they have a similiar problem, as might the rest of the neighborhood if they're on the same utility transformer. All current will return to it's source.

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Magnettica

Here is the link: http://ecmweb.com/grounding/electric...uth_grounding/


The Shocking Truth About Grounding Electrode Conductors

Nov 1, 2006 12:00 PM, By Edward J. Osoliniec, P.E., Engineering Consultant

Have you done any service work lately, and noticed a spark as you connect or reconnect the grounding electrode conductor to the ground rod of what appeared to be a perfectly normal electric service? Have you ever disconnected the grounding electrode conductor at a water pipe and received a shock? Have you ever noticed any arcing or sparking at a loose grounding electrode conductor at an outbuilding that has a connection to its own separate ground rod? If you answered “yes” to any of these questions, the culprit is more than likely currents in the grounding electrode conductor.


Fig. 1. Open neutral with grounding electrode serving as return current path.
Although electricians often attribute these phenomena to “phantom” currents or some sort of mysterious phase imbalance, the condition is usually due to a much different source. Many times, grounding electrode conductors regularly carry current. Many electricians assume the only time there will be current in a grounding electrode conductor for a properly wired system is during a fault. This assumption is usually based on the definitions presented in Art. 250 of the NEC, specifically the interpretations and misinterpretations of 250.2.

The requirements of 250.2 tell us that an effective ground fault current path is, “An intentionally constructed, permanent, low-impedance electrically conductive path designed and intended to carry current under ground fault conditions from the point of a ground fault on a wiring system to the electrical supply source and that facilitates the operation of the overcurrent protective device or ground fault detectors on high-impedance grounded systems.”


Fig. 2. Current returns through all paths, not just the path of least resistance.
Although this section of the Code clearly describes the function of proper bonding, particularly for low-voltage systems, use of the word “ground” in the definition sometimes gives the impression that the grounding electrode conductor is part of the fault-clearing path, and that the currents are only temporary, lasting only until an overcurrent protective device opens the circuit. With that assumption, and based on that incorrect interpretation, many electricians assume that in a properly functioning electrical system, currents in grounding electrode conductors are only present during faults — and only for a very short time. Although further examination of 250.4(A)(5) should make it clear that the earth shall not be considered an effective ground-fault current path, misconceptions persist.

The case of the open neutral. In a properly functioning electrical system, the neutral conductor carries the imbalance current of the system. For a single-phase system, the imbalance is the difference between the currents in the two “hot” legs of the transformer. For a 3-phase system, the neutral current is the imbalance between all three hot phases. To further clarify this point, let's review an example, starting with the review of a single-phase 120/240V system.

The current imbalance needs to return via the neutral conductor back to the transformer. But, if that neutral is open, the imbalance current will seek other paths to get back to the neutral leg of the transformer. At the main service, the neutral and ground are connected via the main bonding jumper. If the ground path has a low enough resistance, it may prove to be a satisfactory return path, and the imbalance current will travel through the main bonding jumper into the grounding electrode. Since the transformer neutral is grounded by the utility, and since the main bonding jumper connects the neutral and grounding conductor at the service, as per NEC requirements, the ground path provides a complete return for the imbalance current.


Fig. 3. An open neutral in a neighboring building, shown on the right. The imbalance current from the neighboring building finds a path back through the water pipe in common to both buildings, and up through the grounding electrode conductor of the building on the left.
Many times, the first clue to finding an open neutral in your system is to measure a potential difference at the various loads in a building. With the absence of a neutral conductor (or a high-resistance return path), there is no path for the imbalance current to return back to the source. When the neutral is open, and there is no return path at all, the entire system becomes a 240V series system. In the case of an open neutral, when the ground path is of high resistance, the open neutral becomes evident as the voltage difference between the phases. In the case of an open neutral with a low-resistance ground path, the open neutral may never be detected. Currents may continue to travel this path for years until an unsuspecting person opens the ground circuit, potentially placing them in harm's way.

Typically during a service upgrade project, you're likely to disconnect the old grounding electrode conductor and replace it with a new conductor properly sized for the upgraded service and the new service ampacity requirements. You may also find yourself disconnecting a grounding electrode conductor during routine repair work or electrical system maintenance. It's at this point in the work process that you can expose yourself to a dangerous or potentially fatal shock (Fig. 1 on page C14).

The path of least resistance. All of us in the electrical industry have been conditioned with the phrase “current travels through the path of least resistance.” But is this really true? Some people conclude that when there are multiple paths for current to flow, current only flows through the path of least resistance. However, a more accurate description of current flow back to the source is that the majority of current flows through the path of least resistance, and less current flows through paths of higher resistance (Fig. 2 on page C16). Given multiple paths back to the source, current will flow through all paths to reach its destination, with the majority of current flowing through the path of least resistance.


Fig. 4. Building on right has open neutral. Imbalance current returns via cable television coaxial jacket to building on left, and then to transformer.
Almost every electrical system has multiple grounding electrodes; ground rods, water pipes, building steel, etc., with a grounding electrode conductor to each. A service with multiple grounding electrode conductors that has a higher resistance on one of the conductors, and little or no measurable current in it, may still have significant current in the other grounding electrode conductors. Therefore, measuring the current in the conductor going to the ground rod and proving it safe does not mean there is a safe current level in the conductor going to the water pipe.

Your neighbor's problem is now your problem. Let's take a look at another example. This time you're working in a building or a house, and you're sure there is a continuous neutral. You look at the service entrance conductors, and don't see any breaks. Everything appears to be in good condition, including the neutral conductor and all neutral connections. You are convinced that since there have been no complaints about fluctuating voltages, or any other indications of an open neutral, that a neutral problem at this building doesn't exist. You even go as far as measuring current in the neutral, and convince yourself that since there is current in the neutral conductor, there can't be an open neutral. This leads you to have no fear of opening up any grounding electrode conductors. Is this a safe assumption?

Even though the building you're working on may have a completely continuous neutral back to the transformer, the house next door or a building somewhere in the general vicinity may have an open neutral. If the building you're working in and the building with an open neutral have some type of conductive path between them, current may return via that path. A metal water pipe is a good example of such a connection. Current can come “up” through a ground rod or a water pipe into the building you're working on, due to an open neutral in a neighboring building. Figure 3 on page C16 illustrates this condition. The metal water pipe common to the buildings has such a low resistance, that it may not be apparent at the building with the open neutral that there is a problem. The current exits the building with the open neutral through the metallic pipes and finds its way back up through the grounding electrode conductors in your building. Any grounded electrically conductive path between buildings can serve as a return path for current for a building with an open neutral.

The grounded coaxial braid in the jacket of cable television drops can also serve as return paths for the neutral imbalance current from a building with an open neutral (Fig. 4). Cable television systems should be grounded as they enter the premises as per Art. 680 of the NEC. Since the cable television connection blocks typically get grounded directly to the same grounding electrodes that the electric service uses (or they have their own separate grounding electrode, and that electrode gets bonded to the electrical system grounding electrode), this can become a return path. However, this situation is quite rare, since the ampacity of the return current tends to burn out the coaxial cable). Nonetheless, it can still exist and create a hazard.

Is the current coming or going? So now you're convinced that there can be current flowing in a grounding electrode conductor. Next time you're on-the-job, use your ammeter to measure the current in the grounding electric conductor before you open up that connection. If you measure a current, how do you know if it's due to current going “down” into the ground at this building or current coming up through the grounding electrode conductor in your building and returning back to the source via your neutral?

Unfortunately, putting an ammeter on the conductor will only prove that there is current flowing in the conductor. It does not tell you the direction of that current. You must use Kirchoff's Law to determine the direction of the current flow. Kirchoff's Law states that all currents entering a connection are equal to the currents leaving a connection. Simply put, all currents must balance. Let's look at a couple of examples for clarification.

Example No. 1. You're working on a single-phase, 120/240V service. You measure 11A in the black conductor at the main service panel. You measure 5A in the red conductor at the main service panel. On a single-phase service, the neutral current is the difference between the two legs of the transformer, which in this case is 6A. Therefore, if you measure 6A in the grounding electrode conductor and 0A in the neutral service entrance conductor, you can be relatively certain that the neutral is open, and your building is dumping current into an alternate return path (i.e. the grounding electrode).

Example No. 2. You're working on a single-phase, 120/240V service. You measure 11A in the black conductor at the main service panel. You measure 5A in the red conductor at the main service panel. As in the first example, the neutral current will be the difference between the two legs of the transformer, which is 6A. However, this time you measure 8A in the grounding electrode conductor. How can this be? Can there possibly be more current being dumped into the ground by the system you're working on than the system imbalance current? Are there 2A of extra phantom current? When you measure the current in the neutral, you find 14A. Now you're really confused. Applying Kirchoff's Law to the circuit, you quickly realize that the 6A of current imbalance from the system you're working on is being joined with 8A coming into this system from somewhere else.

Final thoughts. Neutral current will return to its source via any means possible. That return path could be through a conductor or connection that may seem unlikely to you, such as a grounding electrode conductor.

As electrical services in some neighborhoods around the country age — and the likelihood of an open neutral is more probable as well as in areas with high population density where at least one open neutral may exist — neutral currents seeking return paths through what may be considered unconventional means become more likely. In any and all cases, shock hazards can exist with all electrical conductors, including grounding electrode conductors.

Osoliniec is a private consulting engineer located in Warren, N.J. He is a licensed professional engineer and electrical contractor in the state of New Jersey.

Things to Consider

Never assume that a grounding electrode conductor is “dead,” or you may be.

If there is no current in one of the grounding electrode conductors, this doesn't mean there is no grounding electrode current flowing somewhere in the system. Treat all grounding electrode connection points individually.

Always assume the grounding electrode conductor is “hot,” and treat it as such, until proven otherwise.

Even though the system you're working on may be functioning correctly, and have a good neutral, a dangerous condition may still exist if there is an open neutral in a neighboring building.

Even if the main circuit breaker in the building you're working in is open, as long as the neutral provides a path for that imbalanced current, current can be flowing up through your grounding electrodes, and back through your neutral.

Current can come into the system you're working on from a local faulty system.

The neutral in the building you're working on was sized for its own service, not for additional current from another service. If a neighboring building has an open or faulty neutral, it may affect the system you're working on.

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jrclen

Great post Magnetica.

Magnettica

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JohnJ0906

Absolutely. Thats a good article.

I know you didn't write it but we'll give you some credit anyway.

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All replies based on the 2008 NEC

Shipwreck

Is there a water pump servicing the house or is it a municipal source???I once experienced a shorted pump winding energizing the water system and exterior of an entire mobile home

Hidyusbeast

another possibility: caused by sub panel without isolated neutral bar from grounds( a buddy of mine said he experienced this before as result.

woodchuck2

Almost a year and a half and still looking for the problem?

mrmike

another for this post Magnettica & all- a lot learned here-hope to always retain it...........

Burby

If none of the above proves to be the fault, see if any work has been done on the house recently.

Last year or so, I was hired to replace the flashing on a house. The house had a new roof put on, the roofers didn;t want to mess with the siding, 1x8 cypress, they were afraid they would break it trying to pry it away to install new flashing.
They had tried a few places and sure nuff each pc cracked on them.
So I was asked to install the flashing.
I have never been electrocuted like this in my life, no joke.
We had had some rain the night before or the house had been pressure washed, one or the other. The ground was damp anyhow.
I placed my ladder on the roof, climbed up and kind of laying side ways on the alum ladder I began to remove the siding.
My pry bar heal against the alum flashing & as soon as I began to pry, I began flopping around on that ladder like a fish outta water. My cheek bone got burnt, as well as my elbow. my knee, (shorts on) & my ankle.
I could not let go of that bar until finally I reached inside myself and with all I could muster just threw my weight back and was enough to pull m hand free from the pry bar.

Finally discovered a pc of the siding the roofer nailed back in & in doing so it hit a wire in the wall & was dead in the center of the wire when I cut out the drywall to see if it was from the nail on the outside. Where the wire had been curled before goig into the outlet box in the bedroom it was up gainst the outside wall and his nail got it.

In looking for why, everything on the outside of that house that was metal was hot, from 115 to 120 volts, metal lights, wrought iron railings, all the flashing, if metal it was hot, including some nail heads I tested from the ladder to the head of the nail..

It took hrs for me stop feeling the voltage in my heart it seemed & days for the burns to heal.
Thn longer befoe I would touch flashing or house metal without testing first hahaha,

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mickeyco

Never? First time? Shocking.




.

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tinner666

A house I owned some years back had an electrical imbalance as described. Could get 'juiced' really good while taking a shower. I had VAPWR ( In Va, we pronounce it vapor) come out 10 times. Always checked out when they tested. An electrician friens came over a feww times. Same deal. Finally hooked up about 300 amos of crap and it imbalanced 180v/60! Bleww some stuff, dimmed others. We traced it to the neutral at the head on the house. It had gotten corroded insie the connector.

@ years ago, I went to do a mod-git roof. I was worried about the flame stating a fire. Loaded the roof and started to cut my metal for the drip edges. As I was cutting 1 lenght, I laid it along the eave for measurement and as it contacted the existing metal, the roof caught fire. No shock though. The aluminum sidng, the gutters, and the drip edges were all energized. I couldn't find the source, so I unloaded the roof, after starting another fire to prove to the GC I wasn't BS'ing! Took an electrician 3 weeks to sort it out.

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InPhase277

This thread is so old, the OP has probably been electrocuted by now. We all missed the funeral

MALCO.New.York

Noobs!!!! Gotta Luv 'Em!

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Burby

Nope, I guess because the roofers were standing on the roof when ever they touched the flashing so never completed the circut or because of the water on the house & ground, alum ladder, my metal bar with me to connect both that made a complete circut.. I dunno that part, just know the end results.. Funny now looking back and hearing my worker describe me floppin on that ladder and he didn;t want to climb on the ladder as well, ect ect. It probably didn;t last more than a few minutes, but sure felt like a lifetime to me.
I can imagine if I was him even, thinking wtf he doing? Because nothing there other than flashing, siding, & one attempting to make a swap out.
I wish I had got a quick shock first, then I would have tried to figure it out before going further.

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MALCO.New.York

There may be a screw in a Hot somewhere. It can be found with a Field Strength Meter.

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mickeyco

I was goofing, if you get electrocuted you are dead, you were shocked.







.

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Burby

I am shocked to learn this.. hahaha, thank you for clarifing that for me. But a the time I had been shocked more times than I can count in my life working live, but, phew, to me, that day, I felt I done been electrocuted, kind of like I was sitting in that big chair ya know??
The way that felt that day, I never gonna cross the line that much that could possibly put me there, cause I no like gettig shocked any more, in any way & have a whole new respect for electricity, moisture, & alum ladders..

Merry Christmas to you & yours Mickey

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