Grounding/Bonding rooftop panels and Inverter to AC panel?

[fisherman]

Good Morning,

Offgrid cabin here. Currently running a small generator into my AC panel but plan to install solar soon. So the generator would then connect to the inverter and supplement the batteries when needed or when needing more power.

I'm planning on mounting a few rooftop panels for my setup and was wondering if someone could explain how to bond/ground them. I already have a grounding plate 2ft in the ground that is tied to the A/C panel in my cabin.

When installing the panels and inverter, how should they be bonded/grounded within the system to connect to the AC panel in the cabin?

Thank you

 

[Stephen InGeorgia]

I have my inverters housing and panels going to a dedicated ground rod, but only because they are on the other side of the house from my electrical panels. The inverter output goes to my panels and is also grounded/bonded at the panels from the utility.
If you have access to your ground plate and its big enough for a lightning strike, I'd just run a dedicated wire to its connector from your inverter housing and panels on the roof. You can not go wrong with a dedicated ground rod for the panels as a strike will likely occur there. Then you can ground your inverters to the panels via a separate ground wire. Remember, only 1 location should be bonded Neutral to the Ground.

 

[fisherman]

I have my inverters housing and panels going to a dedicated ground rod, but only because they are on the other side of the house from my electrical panels. The inverter output goes to my panels and is also grounded/bonded at the panels from the utility.
If you have access to your ground plate and its big enough for a lightning strike, I'd just run a dedicated wire to its connector from your inverter housing and panels on the roof. You can not go wrong with a dedicated ground rod for the panels as a strike will likely occur there. Then you can ground your inverters to the panels via a separate ground wire. Remember, only 1 location should be bonded Neutral to the Ground.

Thanks for the explanation! On my setup the neutral is bonded to the ground inside my service panel inside the cabin.

So it's ok to have multiple locations in the setup going to earth ground (such as panels, inverter and electrical panel)? But only 1 spot for neutral-ground bond?

 

[Steve_S]

Do NOT ground the panels to anything but their own ground rod/plate. The Frames & Metal rails if used are Not Electrical, this is for Lightning protection only and need to be separate from your electrical system.

AC = Hot, Neutral & Ground. --> goes to earth ground rod/plate.
DC = Positive, Negative (not neutral)
DC Ground = Lightning Safety Ground. Independent of AC systems. Lightning suppression is suggested.

 

[meetyg]

Do NOT ground the panels to anything but their own ground rod/plate. The Frames & Metal rails if used are Not Electrical, this is for Lightning protection only and need to be separate from your electrical system.

AC = Hot, Neutral & Ground. --> goes to earth ground rod/plate.
DC = Positive, Negative (not neutral)
DC Ground = Lightning Safety Ground. Independent of AC systems. Lightning suppression is suggested.

Are you sure about this?
I have seen suggestions not to put additional ground rods because of a possibility of ground loops and/or surges actually entering your system from the ground if lightening strikes at one point and you have multiple ground rods.
Would this be correct for residential AC ground too?

 

[Steve_S]

I go by our code and what the electrician stated.
My AC is actually grounded to the 6" well casing that goes down 24', with 5' of that into the granite.
Solar Array (framework & panels) are connected to a grounding plate which is 35' from the power house.

Always follow codes & regs for YOUR Region, they do vary somewhat.

 

[sparrowhawk]

I have my inverters housing and panels going to a dedicated ground rod, but only because they are on the other side of the house from my electrical panels. The inverter output goes to my panels and is also grounded/bonded at the panels from the utility.
If you have access to your ground plate and its big enough for a lightning strike, I'd just run a dedicated wire to its connector from your inverter housing and panels on the roof. You can not go wrong with a dedicated ground rod for the panels as a strike will likely occur there. Then you can ground your inverters to the panels via a separate ground wire. Remember, only 1 location should be bonded Neutral to the Ground.

In most cases it's not advisable to add additional grounding rods unless they are within a few feet of the original grounding rod. Plus panel grounding is not for lighting strikes, but to keep a static charge from building up.

 

[Hedges]

Do NOT ground the panels to anything but their own ground rod/plate. The Frames & Metal rails if used are Not Electrical, this is for Lightning protection only and need to be separate from your electrical system.

Are you sure about this?
I think chassis of anything electrical (AC or higher DC voltages) should be electrically connected together, and grounded.
Otherwise, fault between PV wire and frame makes it several hundred volts. Also your ground rod, since you gave it a dedicated one.
There is now maybe 500V between the two ground rods. "Step potential", and maybe two conductors within simultaneous reaching distance.

My understanding of US code.
But electrons behave the same in all jurisdictions.
So do earthworms.