Test Question - Troubleshooting

[jxofaltrds]

As pictured, it doesn't...

But you're asking if isolating/insulating the GEC from touching the water lines (beyond 5') and mechanical lines will reduce touch potential. It won't.

There we agree.

I could 'isolate' and make my bond (interior lines) at the disconnect. But that doesn't solve anything.

 

[jxofaltrds]

You gave away the answer too soon, I thought that was obvious with some assumption from the information provided.

I know.

TY for your support!

 

[Ponchik]

Okay... but then why no neutral current on the local system?

Good question.

I did not notice the neutral in the picture had zero amps. When I saw this I remembered my situation.

 

[al hildenbrand]

Mike, since the GEC to the metal water pipe in direct contact with the earth for at least ten feet is required by Code, thus creating a NEC REQUIRED parallel CURRENT path to the current in the service grounded conductor, the current in the GEC is INTENDED and, therefore, cannot be labeled as "objectionable".

"Touch potential" to conductive surfaces is decreased by bonding to the GES, not by isolating, IMO.
Tapatalk

 

[K8MHZ]

I am not try to insult you or anyone else.

I think that this post proves how few can troubleshoot.

What you see is what I got from the homeowner over the phone. I figured it out 200 miles away. Yet no one locally or the utility could figure it out until pressed (shown/told what to do).

I have been troubleshooting electrical systems for decades, and one rule I always follow is to NEVER try to solve an electrical problem based on information given by homeowners (and vehicle owners).

I always test. Never guess.

 

[jxofaltrds]

Mike, since the GEC to the metal water pipe in direct contact with the earth for at least ten feet is required by Code, thus creating a NEC REQUIRED parallel CURRENT path to the current in the service grounded conductor, the current in the GEC is INTENDED and, therefore, cannot be labeled as "objectionable".

"Touch potential" to conductive surfaces is decreased by bonding to the GES, not by isolating, IMO.
Tapatalk

Correct. I was not clear enough. I believe that if the GEC contacts metal parts in the structure before the 5' then the current on those parts from that point is objectionable.

 

[al hildenbrand]

If the HVAC Metal duct and copper water pipes are SYSTEMS they are already bonded, almost certainly, and, again, are INTENDED parallel paths, by NEC. IMO.

Tapatalk

 

[jxofaltrds]

If the HVAC Metal duct and copper water pipes are SYSTEMS they are already bonded, almost certainly, and, again, are INTENDED parallel paths, by NEC. IMO.

Tapatalk

Agree with the HVAC.

Now to the interior lines. If the 'bond' is within the first 5' and the bare GEC 'touches' prior to that point then we have objectionable current on that section of the piping system.

 

[infinity]

I know.

TY for your support!

Assuming that the system were installed correctly and since there was current on the GEC and not on the neutral then the neutral had to be open at some point. Given the answers there were only two real choices (5. Lost utility neutral 7. Neighbor lost neutral). #7 wouldn't be true because there was 0 current on the neutral and if the neighbor lost a neutral some current would also be present on the neutral in the graphic.

 

[jxofaltrds]

Assuming that the system were installed correctly and since there was current on the GEC and not on the neutral then the neutral had to be open at some point. Given the answers there were only two real choices (5. Lost utility neutral 7. Neighbor lost neutral). #7 wouldn't be true because there was 0 current on the neutral and if the neighbor lost a neutral some current would also be present on the neutral in the graphic.

Well said.

Now the main breaker was turned off and the current disappeared. But that was not the question and was done to prove the 'assumption'.

That is how I could 'tell' from miles away.

 

[Smart $]

Mike, since the GEC to the metal water pipe in direct contact with the earth for at least ten feet is required by Code, thus creating a NEC REQUIRED parallel CURRENT path to the current in the service grounded conductor, the current in the GEC is INTENDED and, therefore, cannot be labeled as "objectionable".

...

If the HVAC Metal duct and copper water pipes are SYSTEMS they are already bonded, almost certainly, and, again, are INTENDED parallel paths, by NEC. IMO.

Yeah, but the current we're talking about here may be fault current. Don't know with information provided. However, you may have some current that's incidental and/or unavoidable, but current on a GEC or any exposed part is never intended.

 

[jxofaltrds]

Yeah, but the current we're talking about here may be fault current. Don't know with information provided. However, you may have some current that's incidental and/or unavoidable, but current on a GEC or any exposed part is never intended.

My though but most people disagree with me. :happyno:

 

[hurk27]

Yeah, but the current we're talking about here may be fault current. Don't know with information provided. However, you may have some current that's incidental and/or unavoidable, but current on a GEC or any exposed part is never intended.

But I would believe it is unavoidable in many cases and very acceptable by the NEC, all GEC's are in fact parallel with the utility neutral, they will always share the neutral current proportionally to the impedance of the path, many water pipe GE's are simply a parallel path through the neighbors house GE then back of their neutral to the transformer, these water pipes can be allot lower impedance then the MGN and or the involved service neutrals so having a current on the GEC can be quite normal, sometimes we might see a little of the primary current on this path because the water lines can also parallel the MGN between the houses down the street via the same GEC connections at each house, but I would expect that this current would be very small, a lost MGN connection could raise it a bit but over all it would be small because of the amount of current involved so unless this current is very large or there is a high voltage potential (10 volts or more ) to remote earth from the grounding this is allot of worrying over nothing.

For mike to suggest cutting the water pipe at the 10' mark from the house and put in an isolator to me would make the system much more dangerous because even though it is not an intended current path, it does provide some safety backup for a lost neutral condition, lightly dimming and brightening of lights is a lot better than having all the electronics burning up and or a fire breaking out because of a over voltage condition, a home owner should always be instructed to have an expert check out the service neutral anytime they see lights getting dimmer and brighter, even if it is not by much.

Mike just because you may have current on the GEC it does not mean you have a large difference of voltage potential between equipment or earth, if you think you have a problem then always measure the voltage between the service or grounding system and remote earth, if it is higher then 10 volts then you have a problem, but I have seen many times for it to be around 3 to 5 volts and be very normal because it is nothing but the normal voltage drop of the service neutral, only when we have a body of water where we have people normally in it such as pools and lakes/rivers with boat docks then even 3 volts can be a problem, but when we start seeing over 10 volts we know there is a problem with the neutral or transformer primary neutral or MGN, then we must act.

 

[al hildenbrand]

Yeah, but the current we're talking about here may be fault current. Don't know with information provided. However, you may have some current that's incidental and/or unavoidable, but current on a GEC or any exposed part is never intended.

The NEC is clear that the purpose of the GES (Grounding Electrode System) is to provide an effective low impedance path to operate the overcurrent protection when a fault occurs.

****That is to say, Fault Current is intended to flow in the GES. Period. It's just that simple.*****

The NEC is SILENT about isolating the path of the current in the conductors that comprise the GES. Think about that. A lowly #14 Equipment Grounding Conductor (EGC) out on the end of a branch circuit IS NOT PREVENTED from being connected to EARTH. The instant that happens, the EGC is another parallel path back to the source.

The NEC is also SILENT about deliberately introducing connections of the EGC to Earth. . . both of these silences mean that if there is a circuit completed from the Main Bonding Jumper to Earth and back to the Source as a parallel path along an EGC, or even a GEC, that it just IS.

If that isn't INTENDING to allow current in parallel paths, I don't know what is.

 

[hurk27]

The NEC is clear that the purpose of the GES (Grounding Electrode System) is to provide an effective low impedance path to operate the overcurrent protection when a fault occurs.

Al, your confusing me?????

A GES system is not to provide a low impedance path to operate OCPDs earth can not provide that? were you meaning EGC?

 

[hurk27]

Well said.

Now the main breaker was turned off and the current disappeared. But that was not the question and was done to prove the 'assumption'.

That is how I could 'tell' from miles away.

So why did you put #9 separate from #5??? if #5 was true the #9 would also be true?

sure hope your not witting the test for Ohio's electrical testing

 

[hurk27]

Mike I have no idea of the experience level of the people who had tried to fix this problem before the home owner called you, but we must keep an open mind that there are many out here doing electrical work without much experience, as you found out many of us still guessed the correct answer even without pertinent information, in the past 15-20 years I have found that many of the younger generation does not have the motivation or willingness to learn the trade as we have, to them in most cases it's just another pay check, I call them time clock punchers, the day of career electricians is going fast it seems, today most only want to learn just enough to get by, if they know that the red wire goes here, the white goes here, and the black lands here then they feel that's all they need, have a problem happen and its throw the hands in the air and have some one else fix it, I can understand the frustration when we come upon a problem that a few others have tried to fix only to find that it was so simple to us we can't understand how they can be in this industry, but when the labor force is what it is then many of these company's don't have much choice but to hire them and only hope that they will become more interested and want to learn the craft to it's fullest, but as we see this is not whats happening, it seems the motivation is not there any more.

As a supervisor of a small electrical contractor company (my last life before I woke up working in a steel mill):blink: I had sent many away who wanted a job but didn't have the first clue about electrical, the sad thing was this had to change because more and more we were finding that it was getting harder finding good quality electricians and we found ourself having to try to train them OJT, but it didn't always work out as they would only go as far as they thought they needed, we would always never put them on there own, until they were ready, even then they would be closely watched.

I just hope some how we can turn this around, the world has changed around us is all I can say.

 

[al hildenbrand]

Al, your confusing me?????

A GES system is not to provide a low impedance path to operate OCPDs earth can not provide that? were you meaning EGC?

Sorry Wayne. You're correct that I'm not using GES in the common context. Frankly, I'm struggling for the term that I need to describe the entire grounded service conductor, main bonding jumper, equipment grounding conductors, grounding electrode conductors, grounding electrodes and Earth. I mean, it's a system of some sort, a whole system, and that is what was enticing me to use GES. . . ."system".

The whole mish mash of interconnections, both deliberate and coincidental, of conductive paths along all the conductors in this "system" just listed above, and any conductive paths that exist from connection of the components of the "system" to other conductive surfaces and systems (duct work, piping, structural steel, conductive surfaces of any type), results in the service unbalance current and fault currents travelling in many parallel paths.

EVERY parallel path from the point of entry of the current into the "system" (listed in the first paragraph) will have current in it, because, as we all know, a single current takes ALL available parallel paths back to the source.

 

[hurk27]

Sorry Wayne. You're correct that I'm not using GES in the common context. Frankly, I'm struggling for the term that I need to describe the entire grounded service conductor, main bonding jumper, equipment grounding conductors, grounding electrode conductors, grounding electrodes and Earth. I mean, it's a system of some sort, a whole system, and that is what was enticing me to use GES. . . ."system".

The whole mish mash of interconnections, both deliberate and coincidental, of conductive paths along all the conductors in this "system" just listed above, and any conductive paths that exist from connection of the components of the "system" to other conductive surfaces and systems (duct work, piping, structural steel, conductive surfaces of any type), results in the service unbalance current and fault currents travelling in many parallel paths.

EVERY parallel path from the point of entry of the current into the "system" (listed in the first paragraph) will have current in it, because, as we all know, a single current takes ALL available parallel paths back to the source.

I don't know of any other words to describe it other then the "grounding system", but we also must understand that each part of this system plays very different parts in the electrical system as a whole, one must understand what each part is and what is expected of it to preform its job, its hard to lump it all together, but you are correct in most of the grounding system parallel paths are expected and allowed by the NEC, the reason is simply that if they are in parallel only supports to lowering the impedance of the paths, the fact that the paths are already sized to safely carry the current intended on them then unintentional parallel paths do not pose a safety concern as it would only add to the safety margin of the path, as in redundancy, but we also must keep in mind that there are places where these parallel paths can not be allowed, and we see this when the NEC requires insulated EGC's, but GEC's are not one of them.

 

[ronaldrc]

Current flowing on utility ground because Service Neutral is too small.