A potential code violation that seems to be too elusive and difficult to understand. Please help!

[GuruLal]

I recently had a solar PV system installed in my home, and I'm concerned about potential NEC 2017 code violations. The grounding conductor of the solar system, which is bonded to neutral, is inadvertently connected with the equipment grounding system of my house for my HVAC/Gas lines etc.

A MCT cable is essentially snaked through my attic space into the roof where I've got solar panels. The MCT cable is un-insulated. So the outer uninsulated metal conduit acts a neutral rod, since it is directly connected to neutral wire outside.

This has led to noticeable stray currents and a voltage difference between the ground of my home's outlets and a true earth ground. Additionally, I've observed magnetic field coming from outside the uninsulated metal conduits, raising concerns about the grounding and bonding methods used. I'm seeking clarity on the proper grounding and bonding procedures outlined in NEC 2017, particularly in Article 690, to ensure the safety and efficacy of the installation. I live in the state of North Carolina and they only recognize NEC 2017 as the last approved code by the state. Please help me in identifying where the code violation occurred. See my chicken scratch diagram for how everything is connected and located in the home. This contractor is doing this type of installation day in day out and I believe they are violating the code and installing this in an unsafe manner, esp when the grounding conductor of the solar panels comes into contact with homes other equipment ground way before it is bonded outside. GFCI's wouldn't be able to stop this either.

I uploaded the picture on the following link of my homes setup

https://ibb.co/B3FQk9Y

 

[GuruLal]

The solar MCT conduit is a flexible conduit that weaves through my home and it is in that process of weaving that it has come into un-intended contact with my homes grounding system. Question here is , what happens if a lightning strikes one of the metal enclosures in the top of the roof where solar panels are connected? That surge is going to travel through that conduit blow my HVAC equipments and shock me in the kitchen if I'm toasting a bread. This is also already creating ground loop currents. That MCT conduit because it's bonded outside in the disconnect is a neutral wire and carries current so long as my neutral wire has some current ( which happens for many reasons, load that are unbalanced etc). How is this not a grounding code violation. What I need is your help to identify in 2017 book that this is a Building or structure grounding electrode violation.

 

[Jraef]

I approved this even though it is regarding your own house because you say the work IS being done by a licensed contractor. Generally this sort of posting is rejected if it is a DIY question.

 

[GuruLal]

I approved this even though it is regarding your own house because you say the work IS being done by a licensed contractor. Generally this sort of posting is rejected if it is a DIY question.

It is not a DIY question. I am debating with county officials and the licensed contractor on why this is not a code violation which I strongly believe it is based on many other electricians that I've consulted with. The contractor doesn't want to admit cause it's more work for them to rectify it and the county officials seem to be bit confused about this.

 

[ActionDave]

It is not a DIY question. I am debating with county officials and the licensed contractor on why this is not a code violation which I strongly believe it is based on many other electricians that I've consulted with. The contractor doesn't want to admit cause it's more work for them to rectify it and the county officials seem to be bit confused about this.

Everything I can see in your diagram indicates a properly wired system.

I don't know what the electricians you are talking to are saying, but this is not the easiest thing to explain to someone not in the electrical business.

As far as magnetic fields coming off the conduit, any time current is moving through a wire a magnetic field is being generated.

I don't know how you are measuring voltage differences between your home receptacles and true earth ground but it's all but impossible to do with any accuracy or reliable results unless you have a NASA budget and equipment.

 

[jaggedben]

I don't see anything cleary wrong with the line diagram you posted. It appears that the interconnection of the solar system used a supply side connection. If so then the neutral can be bonded to ground in the PV disconnect; it is essentially an additional service disconnect. The 2017 code is a little vague on this point but the 2023 code says this is how you should do it. Either way that is not the cause of your purported issues.

It is proper for equipment grounding conductors to be bonded to neutral because both must be grounded. But this is only supposed to happen at the service disconnect(s).

It is also proper for gas lines to be bonded. In which case one would expect continuity between the exposed metal pipes.

By MCT do you mean MC cable?

None of what I've said rules out that you might have neutral current on the PV system exposed metal parts through some sort of fluke. For example perhaps someone installed a lag screw to hold down equipment somewhere and screwed into a cable inside the wall, contacting the neutral in the cable and providing an alternate neutral path. Or perhaps there was a previously existing issue that this install just exposed or otherwise called your attention to.

 

[jaggedben]

...
None of what I've said rules out that you might have neutral current on the PV system exposed metal parts through some sort of fluke. For example perhaps someone installed a lag screw to hold down equipment somewhere and screwed into a cable inside the wall, contacting the neutral in the cable and providing an alternate neutral path. ...

Btw I saw that happen once in a few thousand solar projects.

 

[tom baker]

How are you measuring stray voltage?
Some of your comments are incorrect, such as” uninsulsted metal conduit acting as a neutral rod”.

 

[jim dungar]

Proper terminology is very important. You need to understand and use the NEC definitions if you are looking for NEC violations.

In general the simple word ground is often thought of as dirt or earth, but in electrical systems it is really used to mean 'a common reference point'. Think of how you would 'ground' an aircraft, a ship, or a floating house.

 

[GuruLal]

Well this issue got escalated quite quickly after my body sensed a huge electrical field. It manifested in tinnitus pressure type headaches. This would persist even after I completely turned off the solar panels, the inverters etc. Believe or not this does happen to people. There are big communities about this out there as well, but I'm an engineer so I didn't really buy into this stuff until I felt the discomfort. With that aside, I wanted to just strictly focus on what about the installation that is wrong and what could be done better. This led me towards digging into various things


1. Ground loop currents
2. Foreign stray currents

Now I do have about 50 mA of current that appears on the ground wire for my septic system and also coming from the transformer. It's possible that that current found additional pathways to travel through my home wiring and it created a field

I consulted Open AI, chat GPT v.4.0 and it is the closest thing I've gotten that suggests potential code violation but this needs a human level analysis, so I would like to get your take on it.

Me: If the grounding conductor of the solar system the tis bonded to neutral comes into contact with home equipment ground, that must be a code violation right? So follow the conversation and see what you think. We may learn something here together.


AI: Yes, you are correct. If the grounding conductor of the solar system, which is bonded to neutral, comes into unintended contact with the equipment ground of the home's other systems, it can indeed be considered a code violation. Here's why:

1. Potential Grounding Loops: If the grounding conductor from the solar system that is bonded to the neutral gets interconnected with the equipment ground of the home's other systems, it can create grounding loops. Ground loops can lead to stray currents, which can interfere with the operation of some equipment and might lead to potential hazards.
2. Double Bonding: In electrical systems, the neutral-to-ground bond should occur at a single point, typically at the main service entrance. If there's a bond between neutral and ground in the solar system and another bond inadvertently occurs elsewhere due to this unintended contact, this would be double bonding, which can lead to circulating currents in the grounding system.
3. Potential for Electrocution: If there's an unintended contact between the grounded conductor (neutral) of the solar system and the equipment ground of the home, there's a potential risk of electrocution if a fault occurs, and the equipment ground becomes energized.
4. NEC Requirements: The National Electrical Code (NEC) Article 690, which covers Solar Photovoltaic (PV) Systems, stipulates specific requirements about grounding and bonding. In particular, it outlines where and how grounding connections should be made.

Me: Let's expand on this point. How so? How is it a violation? Is it a violation or is it not?

AI: Yes, unintentionally interconnecting the grounded conductor (neutral) of the solar system with the equipment ground of the home can be a violation. Let's delve deeper into this:

1. Single Point of Grounding (Neutral-to-Ground Bonding): The National Electrical Code (NEC) mandates that neutral-to-ground bonding should occur at only one point within an electrical system. This is usually done at the main service panel. When you interconnect the grounded conductor of the solar system (which is bonded to neutral) to the equipment ground of the home, you might inadvertently introduce multiple neutral-to-ground bonding points. This is a violation of the NEC's requirements.
2. Potential Grounding Loops: When there are unintended connections between neutral and ground at multiple points, it can create grounding loops. Grounding loops can introduce stray currents that might not only interfere with the operation of some equipment but can also lead to potential safety hazards. These stray currents can circulate in the grounding system and even cause equipment malfunction or degradation over time.
3. Issues with Fault Current Path: The primary purpose of the equipment ground is to provide a low impedance path for fault currents to flow back to the source, ensuring that circuit protection devices (like breakers) trip and interrupt the fault. By having unintentional connections between the neutral of the solar system and the equipment ground of the home, you can potentially compromise the fault current path, posing risks.
4. NEC Article 690: NEC Article 690 specifically deals with Solar Photovoltaic (PV) Systems. This article has detailed requirements on how PV systems, including their grounded conductors, should be installed. Violating any of these specific requirements would be a code violation.
5. Possible Induced Voltages: When there are unintentional interconnections between the neutral of one system (solar) and the equipment ground of another system (home), it might introduce voltage differences, causing potential equipment malfunction and presenting an electrical shock hazard.

In summary, unintentionally interconnecting the grounded conductor of the solar system with the equipment ground of the home's other systems can indeed be a violation of the NEC and pose both operational and safety issues.

This had such a dramatic impact on my quality of life, I needed to find a solution. So I used every tool I had on my disposal to try to understand.

Here are additional pictures

Screenshot-2023-09-07-at-1-08-35-PM hosted at ImgBB

Image Screenshot-2023-09-07-at-1-08-35-PM hosted in ImgBB

ibb.co

Screenshot-2023-09-07-at-1-00-26-PM hosted at ImgBB

Image Screenshot-2023-09-07-at-1-00-26-PM hosted in ImgBB

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Screenshot-2023-09-07-at-12-54-31-PM hosted at ImgBB

Image Screenshot-2023-09-07-at-12-54-31-PM hosted in ImgBB

ibb.co

Screenshot-2023-09-07-at-12-40-01-PM hosted at ImgBB

Image Screenshot-2023-09-07-at-12-40-01-PM hosted in ImgBB

ibb.co

Screenshot-2023-09-07-at-12-35-47-PM hosted at ImgBB

Image Screenshot-2023-09-07-at-12-35-47-PM hosted in ImgBB

ibb.co

 

[PaulWDent]

I don't see anything cleary wrong with the line diagram you posted. It appears that the interconnection of the solar system used a supply side connection. If so then the neutral can be bonded to ground in the PV disconnect; it is essentially an additional service disconnect. The 2017 code is a little vague on this point but the 2023 code says this is how you should do it. Either way that is not the cause of your purported issues.

It is proper for equipment grounding conductors to be bonded to neutral because both must be grounded. But this is only supposed to happen at the service disconnect(s).

It is also proper for gas lines to be bonded. In which case one would expect continuity between the exposed metal pipes.

By MCT do you mean MC cable?

None of what I've said rules out that you might have neutral current on the PV system exposed metal parts through some sort of fluke. For example perhaps someone installed a lag screw to hold down equipment somewhere and screwed into a cable inside the wall, contacting the neutral in the cable and providing an alternate neutral path. Or perhaps there was a previously existing issue that this install just exposed or otherwise called your attention to.

Wrong: The neutral cannot be bonded to ground in the PV disconnect if that is other than the main service entrance panel, which would be the case when using Enphase microinverters feeding a double pole breaker in the service entrance panel for example.
Neutral must be grounded in one place only in a system and that is a strict rule. A solar system is a "non-separately derived system" and must not have its neutral separately grounded. It must get grounded by strapping the solar neutral to the utility neutral at the same place and ONLY at the same place as solar line connects (through a breaker) to utility line if it is a grid-tied system, that is, in the panel where the solar grid tie breaker is located.
If you are not using microinverters behind each solar panel, but bringing DC down from the roof to a central inverter, there has to be separate conductors for DC+ and DC- and they should be in grounded metallic conduit and must not be connected to the conduit. The conduit may not be used to carry current, AC or DC The inverter decidrs what potential they are at and may ground neither but actually impose a large AC on them

That means there should NEVER be neutral current flowing in exposed metsl parts of the PV system That would be a huge red flag

 

[GuruLal]

This is how the line side panel was tapped into and this is what's fed into the PV disconnect. This image here is what you see inside the main line side panel. Notice they tab the supply side wires and not the load side. Is it supposed to be this way? This system has to completely turn off if there is a power outages situation. I don't have a battery backup either.

 

[wwhitney]

Wrong: The neutral cannot be bonded to ground in the PV disconnect if that is other than the main service entrance panel

That is incorrect for a PV "line-side" interconnection. Which is effectively a second set of Service Entrance Conductors for the PV, and the PV disconnect becomes a second service disconnect. Any service with multiple service disconnects in separate enclosures will have multiple neutral-EGC bonds, one per service disconnect enclosure.

Ideally those different EGC systems from the different service disconnect enclosures will be kept separate from each other everywhere. In practice that is difficult, and the EGC systems from two different service disconnects will often be interconnected downstream. That will lead to neutral current on the EGC systems, since it creates a loop Service Neutral - MBJ 1 - EGC 1 - EGC 2 - MJB 2 - Service Neutral.

Cheers, Wayne

 

[GuruLal]

Wrong: The neutral cannot be bonded to ground in the PV disconnect if that is other than the main service entrance panel, which would be the case when using Enphase microinverters feeding a double pole breaker in the service entrance panel for example.
Neutral must be grounded in one place only in a system and that is a strict rule. A solar system is a "non-separately derived system" and must not have its neutral separately grounded. It must get grounded by strapping the solar neutral to the utility neutral at the same place and ONLY at the same place as solar line connects (through a breaker) to utility line if it is a grid-tied system, that is, in the panel where the solar grid tie breaker is located.
If you are not using microinverters behind each solar panel, but bringing DC down from the roof to a central inverter, there has to be separate conductors for DC+ and DC- and they should be in grounded metallic conduit and must not be connected to the conduit. The conduit may not be used to carry current, AC or DC The inverter decidrs what potential they are at and may ground neither but actually impose a large AC on them

That means there should NEVER be neutral current flowing in exposed metsl parts of the PV system That would be a huge red flag

Paul, You've got a lot here. We need to unpack this, so to begin let me answer some of your assumptions on this system.

1. There are no Micro-inverters behind each solar panel. It is this panel system with a rapid shutdown box. I don't know if the rapid shutdown box still flows DC current down a ground or neutral wire or not. I don't know if the rapid shut downs are for hot wires only. https://www.gaf.energy/timberline-solar/

2. Various strings from the panel come together into a junction box. The junction box inside looks like the following. Here you can see that the MC conduit directly touches the box which then comes into contact with the ground wires.

3. That MC conduit is carrying current from how it's bonded outside. There is some current on my neutral wire, some comes from the transformer but once I engage the solar system, the unbalanced current on the neutral wire chooses to travel upstream through this conduit and loops around with other home equipment ground that it touches.

4. This MC conduit is acting as a current carrying neutral wire that should be completely isolated from other grounding system it seems like, but if the resistance of this conduit with my equipment ground( HVAC) let's say is <1.0 ohms it is in essence a bond that is being created there and that got to constitute a double bonding situation.

 

[PaulWDent]

Well this issue got escalated quite quickly after my body sensed a huge electrical field. It manifested in tinnitus pressure type headaches. This would persist even after I completely turned off the solar panels, the inverters etc. Believe or not this does happen to people. There are big communities about this out there as well, but I'm an engineer so I didn't really buy into this stuff until I felt the discomfort. With that aside, I wanted to just strictly focus on what about the installation that is wrong and what could be done better. This led me towards digging into various things


1. Ground loop currents
2. Foreign stray currents

Now I do have about 50 mA of current that appears on the ground wire for my septic system and also coming from the transformer. It's possible that that current found additional pathways to travel through my home wiring and it created a field

I consulted Open AI, chat GPT v.4.0 and it is the closest thing I've gotten that suggests potential code violation but this needs a human level analysis, so I would like to get your take on it.

Me: If the grounding conductor of the solar system the tis bonded to neutral comes into contact with home equipment ground, that must be a code violation right? So follow the conversation and see what you think. We may learn something here together.


AI: Yes, you are correct. If the grounding conductor of the solar system, which is bonded to neutral, comes into unintended contact with the equipment ground of the home's other systems, it can indeed be considered a code violation. Here's why:

1. Potential Grounding Loops: If the grounding conductor from the solar system that is bonded to the neutral gets interconnected with the equipment ground of the home's other systems, it can create grounding loops. Ground loops can lead to stray currents, which can interfere with the operation of some equipment and might lead to potential hazards.
2. Double Bonding: In electrical systems, the neutral-to-ground bond should occur at a single point, typically at the main service entrance. If there's a bond between neutral and ground in the solar system and another bond inadvertently occurs elsewhere due to this unintended contact, this would be double bonding, which can lead to circulating currents in the grounding system.
3. Potential for Electrocution: If there's an unintended contact between the grounded conductor (neutral) of the solar system and the equipment ground of the home, there's a potential risk of electrocution if a fault occurs, and the equipment ground becomes energized.
4. NEC Requirements: The National Electrical Code (NEC) Article 690, which covers Solar Photovoltaic (PV) Systems, stipulates specific requirements about grounding and bonding. In particular, it outlines where and how grounding connections should be made.

Me: Let's expand on this point. How so? How is it a violation? Is it a violation or is it not?

AI: Yes, unintentionally interconnecting the grounded conductor (neutral) of the solar system with the equipment ground of the home can be a violation. Let's delve deeper into this:

1. Single Point of Grounding (Neutral-to-Ground Bonding): The National Electrical Code (NEC) mandates that neutral-to-ground bonding should occur at only one point within an electrical system. This is usually done at the main service panel. When you interconnect the grounded conductor of the solar system (which is bonded to neutral) to the equipment ground of the home, you might inadvertently introduce multiple neutral-to-ground bonding points. This is a violation of the NEC's requirements.
2. Potential Grounding Loops: When there are unintended connections between neutral and ground at multiple points, it can create grounding loops. Grounding loops can introduce stray currents that might not only interfere with the operation of some equipment but can also lead to potential safety hazards. These stray currents can circulate in the grounding system and even cause equipment malfunction or degradation over time.
3. Issues with Fault Current Path: The primary purpose of the equipment ground is to provide a low impedance path for fault currents to flow back to the source, ensuring that circuit protection devices (like breakers) trip and interrupt the fault. By having unintentional connections between the neutral of the solar system and the equipment ground of the home, you can potentially compromise the fault current path, posing risks.
4. NEC Article 690: NEC Article 690 specifically deals with Solar Photovoltaic (PV) Systems. This article has detailed requirements on how PV systems, including their grounded conductors, should be installed. Violating any of these specific requirements would be a code violation.
5. Possible Induced Voltages: When there are unintentional interconnections between the neutral of one system (solar) and the equipment ground of another system (home), it might introduce voltage differences, causing potential equipment malfunction and presenting an electrical shock hazard.

In summary, unintentionally interconnecting the grounded conductor of the solar system with the equipment ground of the home's other systems can indeed be a violation of the NEC and pose both operational and safety issues.

This had such a dramatic impact on my quality of life, I needed to find a solution. So I used every tool I had on my disposal to try to understand.

"If there's an unintended contact between the grounded conductor (neutral) of the solar system "
Most grid tied solar systems are split phase 240v and feed L1-L2. A centralized inverter may also have a neutral wire from the utility connection which is used for auxiliary purposes. This must not be grounded anywhere in the PV system. Of course any exposed metal parts of the PV system must also have an equipment ground that is not current carrying except under fault conditions.
.
You are dead right that if metallic conduit houses the DC + and - conductors from the solar panels and is the way that the solar panels get grounded then that conduit must not touch any other grounded equipment in the home That is why I would use liquitite for that purpose, as its insulating outer jacket discourages contact with anything else

 

[GuruLal]

That is incorrect for a PV "line-side" interconnection. Which is effectively a second set of Service Entrance Conductors for the PV, and the PV disconnect becomes a second service disconnect. Any service with multiple service disconnects in separate enclosures will have multiple neutral-EGC bonds, one per service disconnect enclosure.

Ideally those different EGC systems from the different service disconnect enclosures will be kept separate from each other everywhere. In practice that is difficult, and the EGC systems from two different service disconnects will often be interconnected downstream. That will lead to neutral current on the EGC systems, since it creates a loop Service Neutral - MBJ 1 - EGC 1 - EGC 2 - MJB 2 - Service Neutral.

Cheers, Wayne

exactly! this loop is killing me, esp when one component of that loop (MC conduit) then touches my other ground systems that are only connected to my subpanels. It raises its voltage potential to higher potential than what it would have been if its wasn't touching it. Why isn't this a code violation?

 

[PaulWDent]

That is incorrect for a PV "line-side" interconnection. Which is effectively a second set of Service Entrance Conductors for the PV, and the PV disconnect becomes a second service disconnect. Any service with multiple service disconnects in separate enclosures will have multiple neutral-EGC bonds, one per service disconnect enclosure.

Ideally those different EGC systems from the different service disconnect enclosures will be kept separate from each other everywhere. In practice that is difficult, and the EGC systems from two different service disconnects will often be interconnected downstream. That will lead to neutral current on the EGC systems, since it creates a loop Service Neutral - MBJ 1 - EGC 1 - EGC 2 - MJB 2 - Service Neutral.

Cheers, Wayne

a You are dead wrong

 

[GuruLal]

"If there's an unintended contact between the grounded conductor (neutral) of the solar system "
Most grid tied solar systems are split phase 240v and feed L1-L2. A centralized inverter may also have a neutral wire from the utility connection which is used for auxiliary purposes. This must not be grounded anywhere in the PV system. Of course any exposed metal parts of the PV system must also have an equipment ground that is not current carrying except under fault conditions.
.
You are dead right that if metallic conduit houses the DC + and - conductors from the solar panels and is the way that the solar panels get grounded then that conduit must not touch any other grounded equipment in the home That is why I would use liquitite for that purpose, as its insulating outer jacket discourages contact with anything else

Liquidate is all polymeric right? The DC wires need to be in the metal enclosure ( and that's a good thing), it really cuts down on all that E-field and magnetic field from my living space but it needed the outer surface to be insulated. Something like this, https://www.digikey.com/en/products/detail/hellermanntyton/LTP20G-25M/7794609?utm_adgroup=&utm_source=google&utm_medium=cpc&utm_campaign=PMax Product_Category_Cables and Wires&utm_term=&utm_content=&gclid=Cj0KCQjwz8emBhDrARIsANNJjS4DYh3ZDBCJqP6TpAQxmDaSFZMhlyhxuGIxl78GAY4lP4BgQsEpfngaAmSPEALw_wcB

So what I'm trying to do is get the country officials to understand why this is a code violation so this solar contractor will do this rectification work without me having to pay for it. So help me with how I get the county officials to buy into this? So far, they are like they have it wired up right and I'm like they are violating grounding protocols.

and this is going back and fourth.

 

[wwhitney]

You are dead wrong

Well, we are not going to resolve this disagreement by calling each other wrong, I'll just wait for others to chime in to demonstrate that my statements reflect the consensus understanding.

Cheers, Wayne

 

[GuruLal]

a You are dead wrong

I had one other electrician thought that bonding in 2 places is a code violation but the county inspector sided with the contractor that it is correct to have a bond in that disconnect as well as the main line. So there is something to be learned here regarding what is going on. For me, I just need to fix this darn thing so I can start living in my home and be able to sleep in it. I didn't have this problem prior to this solar installation but I am having that problem now. So one of you "Angels" are going to help me fix this. I know it