Grounding Questions (Fuse panel, grounding rod, frame of panels)

[chexed]

Hello from Maryland! First let me say this is an awesome forum! I've checked out a few other threads and I think I'll be a (slow, but) regular here

I've attached two photos to show my solar panel set up. It's only a 200 watt 12v system. The Renology kit I got a few years ago didn't say it required grounding, so I didn't. It was a good chunk of money to invest in a "fun educational project" so anything I didn't have to do wasn't done right away. Now I'd like to top the project off properly!

I have three questions all related to grounding, which I'm about to do:

[B]

[max2k]

Hello from Maryland! First let me say this is an awesome forum! I've checked out a few other threads and I think I'll be a (slow, but) regular here

I've attached two photos to show my solar panel set up. It's only a 200 watt 12v system. The Renology kit I got a few years ago didn't say it required grounding, so I didn't. It was a good chunk of money to invest in a "fun educational project" so anything I didn't have to do wasn't done right away. Now I'd like to top the project off properly!

I have three questions all related to grounding, which I'm about to do:

[B]

I think your questions were cut off, please repost. Did the kit came with installation instructions which would outline grounding requirements as well?

[Sunking]

What do you think Ground is for?

Not required unless it is part of your home wiring system. It does not do anything.

[chexed]

My questions did get cut off:

1. The grounding rod I have is 44" long, is it ok to leave a few inches out? It's right next to a building. I deduced here it's basically OK.
2. Is it OK to leave the insulation on the grounding wire (it will be run along an aluminum sided shed & inside it)
3. Am I grounding the fuse box properly (from negative pole to ground)?

What do you think Ground is for?

Not required unless it is part of your home wiring system. It does not do anything.

I've read that panels are prone to lightning strikes and grounding can prevent some damage. The utility pole about 17 feet away from the panels has been struck multiple times over the years. The panels have bolt holes which the panel diagram says is for grounding (though the instructions with the kit didn't mention using it). Also, my final driving factor was an inline fuse from panels to charge controller blew, so this is the first thing I'm ruling out since I wanted to do this anyway.

I don't know if it is truly beneficial to ground the fuse box. I read there may be interference or static buildup. I plan on hooking up some Arduino/Raspberry Pi prototyping boards with exposed electronics and thought it might be of some benefit. I've read so much at this point, it's basically a bowl of spaghetti in my head spilling out towards grounding - though I did read grounding it to a large metal object might be good enough, maybe even better to prevent interference from the ground itself. Or maybe I'm the only thing that needs to be grounded regularly, so I don't zap my electronics. I just figured I'd use the same ground I'm putting in for the panels to keep it simple. I had to overcome paralysis by analysis. Thank you for taking a look over it. Any criticism is more than welcome!!!

[Edit] I will also have some outdoor lighting.

[Mike90250]

Wow. if your power pole has been hit several times, you are in a high danger zone for lightning. Al the outdoor metal on your array should be grounded and you should ASSUME you will be hit, or even a near miss will induce enough current in your wires, to ruin your day,
Perhaps you can contact the utility that owns the pole and see if a Franklin Rod can be installed to direct a strike to a good ground point

If your array gets hit, or a side streamer hits it, you won't be happy and neither will your gear, grounded or not.. Grounding helps divert the power safely to a good ground, without burning your house down. Assume all electronics will be fried. Bummer.

[chexed]

Wow. if your power pole has been hit several times, you are in a high danger zone for lightning. Al the outdoor metal on your array should be grounded and you should ASSUME you will be hit, or even a near miss will induce enough current in your wires, to ruin your day,
Perhaps you can contact the utility that owns the pole and see if a Franklin Rod can be installed to direct a strike to a good ground point

If your array gets hit, or a side streamer hits it, you won't be happy and neither will your gear, grounded or not.. Grounding helps divert the power safely to a good ground, without burning your house down. Assume all electronics will be fried. Bummer.

I think it got struck 3 times and replaced at least once in the past 15 years. That's what people say in the neighborhood, but I didn't see it happen myself (although I did see the top of the pole was burned worse each time). New pole photos attached for curiosity's sake. No lightning issues since they put this new pole in, except a utility truck driving down the road forgot to put their bucket down and snapped 4 nearby poles (luckily no one was hurt) which caused some kind of surge blowing out all of our surge protectors (getting a bit off topic, but photo attached).

[max2k]

I think it got struck 3 times and replaced at least once in the past 15 years. That's what people say in the neighborhood, but I didn't see it happen myself (although I did see the top of the pole was burned worse each time). New pole photos attached for curiosity's sake. No lightning issues since they put this new pole in, except a utility truck driving down the road forgot to put their bucket down and snapped 4 nearby poles (luckily no one was hurt) which caused some kind of surge blowing out all of our surge protectors (getting a bit off topic, but photo attached).

Interesting place you live in Hasn't driver noticed something was up after the bucket downed the first pole?

[Sunking]

I have looked at your drawing. You have no need to ground anything. If you ground the panels, then they can be hit by lightning. What you CANNOT DO as it violates all codes is ground it like you have drawn up. YOU CANNOT SINK AN ISOLATED GROUND ROD IN THE GROUND. It has to be bonded to your AC SERVICE GROUND. Do it you way and you are guaranteed to have damaged equipment, possible fire, and electrocution if lightning strikes anything in your neighborhood.

Put it to you in another way. You do not know what you are doing, and what you think you know can get you killed.

Anyway if you want to bond the panel frames, then Ok. No ground rod needed. Find your AC Service Meter. Right below it should be a Ground Rod. Run a bare solid copper wire no smaller than the circuit conductors (the two wires from the panels to controller) and connect it to the AC Service Ground Rod. No fuses are required or needed between the panels and controllers. DO NOT CONNECT any ground to the controller or anything else. If you do, you just invited lightning in the house and will need a lot more than you have shown to make it a Grounded System. You want to FLOAT a 12 volt battery system.

[sdold]

If he's under 2017 NEC, would 250.54 allow his ground rod to remain separate from the GES if his ground rod isn't required by code? I wonder if it's technically allowed as an "Auxiliary Electrode." This is a code question, not a "Wouldn't it be OK if..." question, which of course it isn't for the reasons you stated.

[Sunking]

If he's under 2017 NEC, would 250.54 allow his ground rod to remain separate from the GES if his ground rod isn't required by code? I wonder if it's technically allowed as an "Auxiliary Electrode." This is a code question, not a "Wouldn't it be OK if..." question, which of course it isn't for the reasons you stated.

The answer is yes and no. I will only explain the NO Answer.

No because every jurisdiction that has adopted 2017 has amended 690.47(D) out of the code because it is deadly. It is the only code in NEC that threatens life, property, and equipment damage. Stop and think about it Steve. If lightning were to strike nearby, does not have to be a direct strike, the potential voltage difference between the two isolated grounds would be measured in THOUSANDS of VOLTS.

I know what you are driving out. The Auxiliary Ground Electrode just allows you to use a rod on something like a CNC machine which is already bonded to ground via the EGC But if you were to do that, would force lightning Equaling Current to flow through your machine and building wiring system.

Here is Grounding explained in as simple of terms you can use.

[QUOTE]1. Bond everything below dirt together aka your Ground Electrode System. (GES)
2. Bond everything above dirt together. aka your Equipment Ground Conductors (EGC)
3. Bond steps 1 and 2 together with 1 wire only aka Ground Electrode Conductor (GEC)
Result is currents that flows in either above dirt and below dirt CANNOT FLOW BETWEEN EACH OTHER. Does Single Point Ground make sense now? For currrent to flow, it mush have a point to enter, and another point to exit or 2 nodes. In a Single Point Ground there is only 1 node.

Watch this video by Mike Holt. you will my smiling face in it.

[Raul]

So the key is to have only one path to below dirt. It's that right?

[bcroe]

The way I understand it, its really important that everything inside a building be tied to a single wire
to a building ground. In my case, the solar array metal frameworks are directly grounded by 48
concrete posts, hopefully effective for lightning. They are also tied by 6 gauge wire (maybe 600')
to the house ground, for personal safety against equipment faults. I could imagine some lightening
current flowing outdoors between array and building.

I'm not sure how this might be unsafe or could be improved upon. Bruce Roe

[Sunking]

So the key is to have only one path to below dirt. It's that right?

Absolutely correct.

Watch this 6 minute clip from Mike Holt. It is the meat and potato answer to to NEC 250.54 and the abortion of NEC 690.477(D)

[max2k]

The way I understand it, its really important that everything inside a building be tied to a single wire
to a building ground. I my case, the solar array metal frameworks are directly grounded by 48
concrete posts, hopefully effective for lightening. They are also tied by 6 gauge wire (maybe 600')
to the house ground, for personal safety against equipment faults. I could imagine some lightening
current flowing outdoors between array and building.

I'm not sure how this might be unsafe or could be improved upon. Bruce Roe

I understand it that all above ground is bound together and all below ground is bound together by a separate conductor. Then these 2 systems are connected together with single wire. Now your case is interesting- if your array is 600' from the building and experiences nearby lightning strike the current from that strike will flow 2 separate paths- most of it hopefully to the local grounding system which consists of those 48 posts (are they bonded together?) and some will travel over that 6 gauge to the house grounding rod. There will be significant voltage drop created over 600' of the 6 gauge during that moment I think.

[Sunking]

Max you do not understand Step Potential Difference.

Defined is: When current is flowing from Lightning or utility high voltage to the earth ground, the ground potential rises at the entrance point, and a voltage gradient will occur based on the resistivity of the soil, resulting in a potential difference between two points on the ground. This is called a Step Potential as it can cause voltage between a person feet.