Hi, community
I have a roof strike protection, but have no idea how PV grounding should be done and what is the main reason for it?
Is there any guidelines and best practices somewhere, I’d appreciate
Hi Andrii
In many situations is necessary to comply with local electrical requirements.
And, generally, because they are installed high on the roof, have a big surface and got wet first.
It’s better to have them connected up there to a grounding point, instead to allow the high voltage and energy of a lighting to travel down to the inside of the house where the inverter is, inverter which is, for sure, grounded.
Lighting, like any electrical current, is following the shortest path to the ground.
But…
The hardware topology (buck converter) of Victron MPPTs is like the topology of the other brand of inverter you are having.
And on the safety instructions section of that inverter is clearly stated the followings:
WARNING: Because this inverter is non-isolated, only three types of PV modules are acceptable:
single crystalline, poly crystalline with class A-rated and CIGS modules. To avoid any malfunction, do
not connect any PV modules with possible current leakage to the inverter. For example, grounded PV
modules will cause current leakage to the inverter. When using CIGS modules, please be sure NO
grounding.
Alex
Yeah
The question was if I have lightning protection, grounded, already, do I need to put a ground on panels additionally?
You might find this interesting
Section 3
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No PV equipment (panels, inverter, etc) will survive to a direct lighting strike. Grounded or not. That’s for sure!
As per a nearby strike, well, in my opinion, which may be far removed from the truth, if you have a lighting protection for the house, no, no need to ground the panels additionally.
If you ground the panels, you may just “invite” the lighting to “branch” and hit the panels too. Remember, shortest path…
But then again, it may contravene the local electrical regulations.
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You’re not earthing to fix lightning.
A potential can build up for various reasons and it is best practice to earth the frame.
Supposedly, panels at a higher potential are more likely to induce lightning.
We just whacked in a couple of earth spikes near the roof sections and made sure all the panels and frames are earthed.
Lightning protection is fitted inline, but a direct strike will cook anything it touches. If it can blow a hole in a wall and split a tree, panels and cabling are less of a challenge.
We live in a very high risk strike area and have had many a close hit and indeed cooked electronics, but so far all the main gear has been been fine.
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This is exacly what lives in my head - bringing ground to panel’s frame could potentially excite a lightning. @alexpescaru
But now I hear you @nickdb - this is what recently making me think we still need to bring ground to panel’s frame, because it will protect equipment from build up potential, which happens anyway.
Thank you, guys
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Just be careful that the frame is anodized aluminum, meaning it has a protective coating that is non-conductive.
Use proper “crimping” connectors that “dig” into the frame or “scratch” the frame where you connect the grounding.
Also don’t forget the “interaction” and corrosion between different metals.
Have fun! 
Yes, thank you
Going to dig deeper in proper connection organization between frames and aluminium wire, already installed as lightning protection.
I remember there was a specific hole on frames with grounding mark on it.
Many panels have lugs already for this purpose.
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