Bonding and Grounding Solar Components

[DerpsyDoodler]

Could that DC circuit be safely grounded on both ends of that 500ft run?

 

[timselectric]

I guess I should have specified the implied EGC from the panels/mount/local equipment chassis to this grounding electrode? As for where grounding the DC circuit should happen, could it be done at either location? What are the factors to consider?

If it doesn't connect back to the main ground bar.
It isn't grounded. It's just connected to a rod, stuck in the dirt.

 

[DerpsyDoodler]

If it doesn't connect back to the main ground bar.
It isn't grounded. It's just connected to a rod, stuck in the dirt.

That keeps panels and mount at earth potential. Whatever you call "grounding bar" is arbitrary, as long as a fault trips a breaker, right? Presuming the DC circuit is isolated from the house/AC circuit then it would make sense to ground the DC circuit at the panels. Closest to the power source, right?

I don't understand the need for an extra 500ft run from the house to the solar panel/DC circuit grounding electrode.

 

[robby]

As I mentioned to the OP in another thread, I had grounded my array with a 10ft Rod and then bonded it to 5 other 10ft rods that go around my property and to my panel box earth. The Electrician who came into certify the system looked at the bond and insisted that the Panel Array be grounded separately! I argued with him for a minute or two about it causing a ground loop and he basically said that if lightning struck the PV Arrays metal frame it was better that the ground was separate from the rest of the system. I was not convinced by this but he said he was removing the wire before the Trench was filled in and it could not stay if I wanted him to sign off on the Inspection. I off course just let him do what was needed to get the system certified and commissioned. I later added an Eaton Surge protector to the panel box as some added protection.

My huge Ham Radio Antenna is much more of a target than my panels and I think it has been struck once or twice already (That is based on my wife jumping 5 feet in the air when the boom went off plus the sizzling sound of electricity that proceeded it by a couple of milliseconds). Luckily there was no damage to my radio equipment. I use flattened 3/4" copper Gas Pipe welded to three ground rods circling the tower and then that goes around the house to two more 10ft Rods at each corner before connecting to the service Panels Ground bus. I also use gas discharge tubes on the Coax lines and all the equipment chassis are grounded on a copper plate behind the Radio desk and then some #6 down to the closest ground rod outside.

 

[timselectric]

That keeps panels and mount at earth potential. Whatever you call "grounding bar" is arbitrary, as long as a fault trips a breaker, right? Presuming the DC circuit is isolated from the house/AC circuit then it would make sense to ground the DC circuit at the panels. Closest to the power source, right?

I don't understand the need for an extra 500ft run from the house to the solar panel/DC circuit grounding electrode.

This should help you understand.
If you don't want to know everything about grounding. Then, you can just skip to about the 50 minute mark. Where he specifically talks about the solar array.

 

[Zil]

In a non-grid system. The solar panels frame should be connected to one or more ground rods. This is for lightning avoidance. Only.
In a non-grid system. Not knowing the inverter, Im guessing 120/240 volts ac . In the ac current outlet is a green wire that connects to the inverter case. In a non-grid system. There is no reference to earth ground. There is no ground rod needed in a non-grid system. The ground reference is back to the source of the ac, the inverter. You will do little harm having a ground rod in a non-grid system. But no benefit.

 

[DerpsyDoodler]

The ground reference is back to the source of the ac,

Wrong. The ground reference is the zero volt reference. It is not to complete circuits or carry voltage for regular use.

the inverter. You will do little harm having a ground rod in a non-grid system. But no benefit.

Adding a grounding electrode gives excess charge build-up somewhere to dissipate (into the giant mass of earth). As already stated, it keeps the ground circuit (and everything attached to it) at the same 0 volt potential of earth.

I may not be an electrician, but I know enough to be safe.

 

[timselectric]

In a non-grid system. The solar panels frame should be connected to one or more ground rods. This is for lightning avoidance. Only.

Sorry
But this would attract lightning, not avoid it.

 

[timselectric]

I may not be an electrician, but I know enough to be safe.

Your statements, prove this to be untrue.
I guess that you didn't bother to watch the video.
"You can lead a horse to water, but you can't make them drink "
I give up, my time is being wasted.

 

[Zil]

Sorry
But this would attract lightning, not avoid it.

I would need more information about this statement. Maybe a reference? We Need to learn.

 

[Zwy]

I just read over this thread and felt compelled to ask. With regard to neutral ground bond, do you fully understand where and how that is supposed to happen, at this point?

Main point is: for the entire system, this happens once and once only. timselectric described where it should happen.

Also,

@timselectric @FilterGuy

considering the long distance run from his PV mount to his house, why should he run grounding wire all the way from his solar panels?

Yes as it makes all components referenced to 0V potential of earth.

In that case, why not a grounding electrode at the panels and a grounding electrode at the house?

As described previously, any nearby lightning strike creates a voltage potential and could lead to current coming into the house from outside due to the extra ground rod. If instead there wasn't a ground rod present at the PV array, the voltage in the ground gradient would just dissipate into the surrounding ground.

Both are grounded and it wouldnt require 500ft of cable. At that distance, is there risk of a ground loop between the two electrodes?

It isn't about a ground loop but voltage potential from nearby lightning strikes. Mike Holt has this in his videos.

 

[DerpsyDoodler]

Your statements, prove this to be untrue.
I guess that you didn't bother to watch the video.
"You can lead a horse to water, but you can't make them drink "
I give up, my time is being wasted.

I ask direct questions that you ignore and instead continue to point me to a video that I've watched before and have no interest in watching again (btw). I know how breakers work, and I know the purpose of a zero volt reference. So please explain how asking questions should somehow mean I don't know how to be safe.

 

[timselectric]

I would need more information about this statement. Maybe a reference? We Need to learn.

I have installed lightning protection, on commercial buildings. The goal is to provide the easiest path for the lightning strike. Whenever there was grounded equipment, mounted on the roof. (AC units or antennas) we had to add air terminals, mounted higher than the equipment. In order to attract the lightning to the lightning protection system, instead of the equipment. NEC allows, but does not require a ground rod for an array. It only requires that the array be grounded. (With a #6 green wire, ran back to the main service ground) the video I posted a few posts up, gives more reasoning.

 

[fisherus]

An electrical systems Grounding system, has nothing to do with the earth, other than the earth should be connected to it.
I can understand the confusion of thinking this.
Because the earth that we stand on, is also known as the ground we stand on. But, these are two different uses of the word "ground".

Will it be OK to make the connection of the 6AWG wire to the other ground rod lug I have in the ground at my ground mount, run it through the combiner box ground lug, disconnect switch ground lug, through the conduit to the emergency shut-off switches ground lug, then to the inverter ground lug? This makes the most sense to me unless it has to be tied in with the array ground rod. I can separate the two rods by removing the wires I have tied between them.

 

[Zil]

Posted this before post 53. That is true for commercial heavy duty lighting protection on large buildings.
But they don't "attract lightning".

OK I did some fast study. A lightning protection system requires an earth ground. There are different ways to do this. multiple rods driven into the earth is the most common. There are two thoughts on this, ONE; the static is bled into the ground before it builds to a direct heavy strike. Universally accepted by most experts until 50 years ago.. TWO; the strike is directed into the ground by the installed circuits. Presented by some modern experts during the past 50 years. My belief from observation that both are true. There are fewer strikes with grounded systems than with no system.
It is accepted by all; there must be a earth ground, one or more rods driven into the earth. It is also accepted by all, Such system = Will Not Attract Lightning.
It is accepted by code and solar installation experts that solar panel frames must be grounded to an earth ground rod or more. Systems I have examined all have multiple rods tied together with copper wire..

 

[timselectric]

Will it be OK to make the connection of the 6AWG wire to the other ground rod lug I have in the ground at my ground mount, run it through the combiner box ground lug, disconnect switch ground lug, through the conduit to the emergency shut-off switches ground lug, then to the inverter ground lug? This makes the most sense to me.

Yes, that's exactly what you should do.
I can't remember if you have grid available or not.
If so, make sure that it continues to the main service ground.

 

[Zil]

Repeat. A non-grid system has No Reference to an earth ground rod. Except for any lightning protection and that should be outside the system..
In a non-grid system, The ac current references the inverter case for the short circuit protection.

 

[fisherus]

Yes, that's exactly what you should do.
I can't remember if you have grid available or not.
If so, make sure that it continues to the main service ground.

I am totally off-grid.

 

[timselectric]

It is accepted by code and solar installation experts that solar panel frames must be grounded to an earth ground rod or more. Systems I have examined all have multiple rods tied together with copper wire..

This is the problem with the industry. A lot of people truly believe that it's the right thing to do.
But, it's not.

 

[timselectric]

I am totally off-grid.

Ok
Then the inverter is your main service. You'll need a ground rod there. And I would recommend a N/G bond at the loads panel. But, it's acceptable to leave it floating. There are benefits to both. I prefer to bond, but if not, I install fault detection.