Panel grounding to rod at location (not to main breaker due to distance)

[Zwy]

Well the problem I still have is how the ac is getting into the panel frames. I don't think I have the issue myself but others do.

Since the dc cables and dc solar cells are isolated from the frame of the panels then grounding those frames to avoid the weird static ac buildup people are experiencing at the panels themselves makes far more sense to me than running a ground wire back to the house for it.

There is no loop circuit being completed from the house with this weird effect. I fully understand it being needed if the ac was connected to the panel frames or even the dc and it going along the dc wires since ac can piggy back like that. But there isn't supposed to be a direct connection from those dc wires to the frames.

So if its just occurring at the panels and not a loop then grounding the frames at the array makes more sense. It would be like grounding the neighbors ac back to my ground point. Sure it would work but it wouldn't make much sense.

Maybe you should read this: https://diysolarforum.com/threads/eg4-6500-voltage-on-pv-terminals.55201/post-707937

Most inverters do not have isolation of PV to H bridge.

This isn't about whether AC voltage exists on your panel frames today. It might be there tomorrow if a fault occurs inside an inverter and sends AC output to PV. The PV array needs to be bonded to the AC grounding system for this purpose.

 

[zanydroid]

There are multiple cases for AC voltage on panel frames.

+/- AC induced to panel. Low current, no faults needed (just an efficient enough non-galvanic coupling) between the cells and the panel frame). Grounding system will dissipate.

+/- AC shorted to panel from DC conductors. Requires at least one fault. Potentially rather high current. Either ground fault detector will raise alarm and shutdown your system, or the current is high enough to trip the breaker feeding inverter (I don't think this can be relied on).

There's probably several other cases. Rather than grow a big enough brain to figure out all the fault conditions myself, I prefer to just parrot the safety standards...

 

[Gurusi]

I appreciate all of the discussion and advise. my take from this is that even if an auxiliary rod is present at the the lumber ground array, a connection (200ft) to my main panel would be required (depending on the inspector!).

 

[Zwy]

I appreciate all of the discussion and advise. my take from this is that even if an auxiliary rod is present at the the lumber ground array, a connection (200ft) to my main panel would be required (depending on the inspector!).

If NEC is the code, it is required.

On the safety aspect, I would run it anyway.

 

[Starex]

It seems to me that NEC just replaced one set of confusing rules with another set of confusing rules.

 

[Crowz]

It seems to me that NEC just replaced one set of confusing rules with another set of confusing rules.

I always that that was the purpose of NEC stuff was to be confusing

Can't get that convoluted without some effort in the matter.

 

[Starex]

In

I always that that was the purpose of NEC stuff was to be confusing

Can't get that convoluted without some effort in the matter

That’s actually not to far from true.
I was at a lecture by a phd who is supposedly an expert in the field. He said that the hardest thing to protect against is lightning.
When lightning hit a tree, ground, lightning rod etc. an extremely high voltage wave travels through the ground. The voltage difference over just 100 feet can be 1000’s of volts
Shielding from this wave is impossible.
The best you can do is try to keep everything in you house at the same voltage at the same time. No voltage difference, no current flow, no damage.
Hence you want everything connected to a single ground point.
For every configuration NEC comes up with to protect under one circumstance, you can imagine a circumstance where that configuration leads to a damaging/ dangerous situation.
Hence the frequent code changes.
The bottom line is, no grounding configuration is completely protective.

 

[McKravitts]

In

That’s actually not to far from true.
I was at a lecture by a phd who is supposedly an expert in the field. He said that the hardest thing to protect against is lightning.
When lightning hit a tree, ground, lightning rod etc. an extremely high voltage wave travels through the ground. The voltage difference over just 100 feet can be 1000’s of volts
Shielding from this wave is impossible.
The best you can do is try to keep everything in you house at the same voltage at the same time. No voltage difference, no current flow, no damage.
Hence you want everything connected to a single ground point.
For every configuration NEC comes up with to protect under one circumstance, you can imagine a circumstance where that configuration leads to a damaging/ dangerous situation.
Hence the frequent code changes.
The bottom line is, no grounding configuration is completely protective.

Although I completely agree with your post Starex, I believe you just committed heresy.

Nobody wants to take the blame for giving advice about grounding that leads to damage/death. The writers of NEC are among them.
Everyone wants to believe that the ground is "The ground". A nice electrically peaceful safe place that could never be a party to damaging equipment or harming anyone.
It is brave of you to question that belief.
I think I'll start another topic on this forum discussing this in more detail.
I welcome your input.
I'll post the topic title here after I set it up.

 

[BooneMtn]

See Will Prowse's video 2:45 from a year ago, he says to avoid ground loops as they are dangerous.

NEC 2023 says to connect all grounding to the MSP ground only, but also says a separate ground for the array is permitted but not required.

BUT, a secondary ground could give rise to a dangerous earth ground potential between the separate earth ground connections, aka a ground loop, as Will described as dangerous.

This video from Univ Maryland is very helpful and current with NEC 2023 grounding code.

 

[Starex]

I saw one system that was approved by a code inspector in which the designer neutralized the danger by adding ground rods every 6 feet attached to a 2 gauge buried bare copper running in a straight line connecting the array ground to the main facility ground.