Yet another question about grounding a solar power system.

[iamamultitasker]

I've been stress testing my new 24v 5kwh solar power system and it has been perfect so far. So now I'm ready to install the grounding for it and have the following questions which I hope someone can help me with.

1. Can I attach the grounding for the solar panels to the negative bus bar of my system (all the other stuff is grounded to this bus bar) and then run a 6 awg bare copper wire to the grounding rod?
2. Related to #1, if #1 is yes, is it preferable to do a separate wire run to the grounding rod for the solar panels?
3. Would it be better to have a separate grounding bus bar and connect it to the negative bus bar?

The other stuff in my system is fairly straightforward, but the grounding part is still confusing to me. Thanks in advance for any good advice.

 

[sunshine_eggo]

I've been stress testing my new 24v 5kwh solar power system and it has been perfect so far. So now I'm ready to install the grounding for it and have the following questions which I hope someone can help me with.

1. Can I attach the grounding for the solar panels to the negative bus bar of my system (all the other stuff is grounded to this bus bar) and then run a 6 awg bare copper wire to the grounding rod?
2. Related to #1, if #1 is yes, is it preferable to do a separate wire run to the grounding rod for the solar panels?
3. Would it be better to have a separate grounding bus bar and connect it to the negative bus bar?

The other stuff in my system is fairly straightforward, but the grounding part is still confusing to me. Thanks in advance for any good advice.

1. Yes. Only the solar panel frames must be grounded.
2. Your preference.
3. Your preference.

 

[BentleyJ]

It sounds like there may be some confusion or interchanging of the term "Ground" in the description above. If a ground rod is to be installed, we will assume this is a stationary system not an RV or vehicle.

A copper rod inserted into the soil is an "Earth Ground" and is not the same as ground when referring to an automotive application where the negative side of the battery is connected to the chassis, which serves as one of the conductors.

In a stationary solar system, all conductive, metalic components such as PV frames, Conduit, J Boxes, Inverter Enclosure or Chassis & Battery Racking and Enclosures are tied together by a green or bare copper wire that attaches to the Earth Ground Rod.

Unless the Installation manual specifically states to do so. Neither the Battery Negative or the PV Negative are connected to Earth Ground. Earth Ground is a completely separate bus bar and wire.

 

[iamamultitasker]

This is why it's hard to understand this stuff. The Google AI returns and answer closer to sunshine_eggo, but also features many points made by BentleyJ:

Yes, you can connect a dedicated earth grounding bus bar to the negative bus bar in a DC electrical system, but it's crucial to ensure proper grounding practices and safety, especially in mobile applications like RVs or boats.

Here's a breakdown:
Dedicated Earth Ground Busbar:
A dedicated earth grounding busbar is a good practice for safety and to ensure a clean and reliable ground path for your electrical system.
Connecting to Negative Busbar:
You can connect the earth grounding busbar to the negative busbar, which is often connected to the chassis or a designated grounding point.
Safety Considerations:
Ensure that the grounding wire from the earth grounding busbar to the chassis or grounding point is of sufficient size and properly bonded.
Mobile Applications:
In mobile applications like RVs or boats, the negative busbar is often connected to the chassis or engine block, which serves as the ground.
Separate Grounding:
It's important to distinguish between the negative DC busbar and the earth ground busbar. The negative busbar is a return path for DC current, while the earth ground busbar is for safety and fault current paths.
Best Practice:
Connect all ground wires to the earth grounding busbar and then connect that busbar to the chassis or designated grounding point.


Now I'm back where I started. To be clear, yes this is a stationary system hence the reference to a grounding rod. The battery array (2p2s) negatives are connected to the negative busbar, so if I connect the negative busbar to the earth ground busbar then to me it looks like the battery negatives are connected to the earth ground busbar which in Bentley's opinion is either not necessary or simply wrong.

So if I connect the PV frames, inverter case and mppt controller case to the earth ground busbar and then wire this to the earth ground rod, the entire system would be properly grounded?

This is the first system I've put together and I'd like it to be my last as well.

Thanks.

 

[BentleyJ]

The battery array (2p2s) negatives are connected to the negative busbar, so if I connect the negative busbar to the earth ground busbar then to me it looks like the battery negatives are connected to the earth ground busbar which in Bentley's opinion is either not necessary or simply wrong.

Its not my opinion. Unless the manual specifically requires either the PV- or the Battery- to be tied to Earth Ground then its not done. Most all of us on the forum do not have systems with the batt- connected to Earth Ground.

So if I connect the PV frames, inverter case and mppt controller case to the earth ground busbar and then wire this to the earth ground rod, the entire system would be properly grounded?

If by "entire system" you include the breaker panel ground bus and all the receptacles then yes. The Equipment Grounding Conductor is one thing where everything is tied together and ultimately has a path to the ground rod.

 

[sunshine_eggo]

I should have indicated the battery (-) is not required to be grounded unless over 60V, but I don't think it's prohibited.

 

[ricardocello]

This is why it's hard to understand this stuff. The Google AI returns and answer closer to sunshine_eggo, but also features many points made by BentleyJ:

That’s because the AI is learning from this forum, and eggo has over 23,000 posts!
Pretty soon the AI will be posting.

 

[MountainMatt]

I've been stress testing my new 24v 5kwh solar power system and it has been perfect so far. So now I'm ready to install the grounding for it and have the following questions which I hope someone can help me with.

1. Can I attach the grounding for the solar panels to the negative bus bar of my system (all the other stuff is grounded to this bus bar) and then run a 6 awg bare copper wire to the grounding rod?
2. Related to #1, if #1 is yes, is it preferable to do a separate wire run to the grounding rod for the solar panels?
3. Would it be better to have a separate grounding bus bar and connect it to the negative bus bar?

The other stuff in my system is fairly straightforward, but the grounding part is still confusing to me. Thanks in advance for any good advice.

This is a good video that helped me but so did this thread.
Thanks for posting.

 

[J.H.]

This is why it's hard to understand this stuff

Welcome to the party.. been there - felt that …..hang in there ……..it does get better?.