Is ground rod always required for panels? (in an all in one set up)

first of all, please be gentle as i am a total noob lol.

So i have a few panels leaning against my wall, planning to set up with a MPP all in one (so voltage would be up to 100vdc). from what I read so far is that while the all in one inverter will share the ground with the AC (?!?), i will still need to ground my panels separately.

if that's correct, do i have to drive another rod in the ground somewhere, or can i just run a wire and connect it to the ground wire in my main panel? or even a pig tail to a ground wire in a switch?

“Depending on local codes” the panel mounts/frames are electrically connected and the array is attached to an 8’ ground rod driven at the array if that’s what you mean.
I may stand to be corrected but I’ve never seen where the panel negative(-) needs to be grounded before the SCC; I haven’t done it and I can’t think of how that would benefit anything if that’s what you’re asking.

12VoltInstalls said:

“Depending on local codes” the panel mounts/frames are electrically connected and the array is attached to an 8’ ground rod driven at the array if that’s what you mean.
I may stand to be corrected but I’ve never seen where the panel negative(-) needs to be grounded before the SCC; I haven’t done it and I can’t think of how that would benefit anything if that’s what you’re asking.

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it's gonna be off grid, so i haven't checked any codes at all. i was just wondering how critical it is if i dont have one. plus, i might be wrong, but i rarely see anyone talks about it. for instance, in Will's ground array set up, i have never seen him point out any grounding rod.

kaizday said:

it's gonna be off grid, so i haven't checked any codes at all. i was just wondering how critical it is if i dont have one. plus, i might be wrong, but i rarely see anyone talks about it. for instance, in Will's ground array set up, i have never seen him point out any grounding rod.

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I could be wrong, but I suspect that the purpose is for lightening.
I used to explain to people that lightening travels thousands of feet through air, and nothing in that foot long surge protector is going to stop it if the surge protector is the shortest path to ground.

Aluminum frames on solar panels would seem like good lightening rods to me.

My grid tied home solar all connects to the same ground rod. House panel, string inverter, solar panels, all to the same ground rod.

time2roll said:

My grid tied home solar all connects to the same ground rod. House panel, string inverter, solar panels, all to the same ground rod.

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the thing with my house is that i don't see the house ground rod itself. when i traced the ground wire from my main ac panel, it comes from outside of the basement wall, which is underground. so i was wondering if i can just "t-bone" connect to that main ac ground wire or not.

thanks

I would bond the ground connection to that existing earth ground and be done with it.

time2roll said:

I would bond the ground connection to that existing earth ground and be done with it.

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You can certainly do that, but it would seem to me that makes it more likely that a lightening strike finds the way into your house.

Just John said:

You can certainly do that, but it would seem to me that makes it more likely that a lightening strike finds the way into your house.

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oh... are you suggesting me not to bother with grounding/earthing the solar panels? sorry i am a beginner, so I just want to make sure.

thanks

kaizday said:

oh... are you suggesting me not to bother with grounding/earthing the solar panels? sorry i am a beginner, so I just want to make sure.

thanks

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You are free to do whatever you wish with your own equipment.

I'm just pointing out that solar panels don't need grounding for any electrical or operational purpose. (I could also be wrong about that)

If you tie into an existing ground, you are likely to do so by running a wire alongside the actual (required for function) wires already existing.
This gives a nice long run for any lightening strike to decide where to go. I would think that means there is a much greater chance of lightening hitting your panels, and taking out your flat screen television (or whatever else you may have) that is plugged in.

Shortest path to ground with the least resistance is the path it will take.

I did have lightening strike our central air conditioner in the early 1980s, besides melting a big divot in the air conditioner, it took out three televisions and two stereos in the house.

I think a separate ground driven next to the panel location is a good precaution/recommendation, but not required.

Ask or search here for the real experts:

https://forums.mikeholt.com/forums/bonding-and-grounding.22/

Just John said:

You are free to do whatever you wish with your own equipment.

I'm just pointing out that solar panels don't need grounding for any electrical or operational purpose. (I could also be wrong about that)

If you tie into an existing ground, you are likely to do so by running a wire alongside the actual (required for function) wires already existing.
This gives a nice long run for any lightening strike to decide where to go. I would think that means there is a much greater chance of lightening hitting your panels, and taking out your flat screen television (or whatever else you may have) that is plugged in.

Shortest path to ground with the least resistance is the path it will take.

I did have lightening strike our central air conditioner in the early 1980s, besides melting a big divot in the air conditioner, it took out three televisions and two stereos in the house.

I think a separate ground driven next to the panel location is a good precaution/recommendation, but not required.

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i see. thanks much for your response.

I have something similar to you. I don't know what specifically is correct. Never can quite get a straight answer and terminology and code around the world seem to vary. So this is what I have:

I have a small off-grid system and the 2.22kW array on the garage roof is quite some distance from the off-grid AIO inverter and batteries. Like you I have a low voltage PV input limit (105V) so the panels are in a 2S3P arrangement.

I use a combiner box to connect the three strings in parallel, and each string (of 2 panels) is independently fused inside the box. The combiner box also has a surge protection device which I have connected with a wire to an existing ground rod. This is not the same ground rod the home's main supply uses but I figure that doesn't matter since the solar input of the AIO has no option for connection to ground, just the PV + & -.

I have not done any additional grounding of the aluminium rails holding the panels.

The AIO inverter is grounded via the grid AC input connection it has.

time2roll said:

Ask or search here for the real experts:

https://forums.mikeholt.com/forums/bonding-and-grounding.22/

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Good resource. I like the PowerPoint presentation there on the topic. It explains the topic quite clearly.

For those interested, I suggest you read it.