Ok here is another one of these topics in that the more you read to more you get confused. Living here in Florida we get some serious lightning, my panels will be about 150 ft from the inverter. I believe its not advisable to add another ground rod at the panels due to creating a ground loop, so with that do I need to run an additional wire to my main grounding rod.
Solar Panel and grounding questions...
- Thread starter Rocknemo
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BentleyJ
Solar Wizard
Yes, any metal frame, chassis, enclosure, junction box or conduit needs to have an Equipment Ground. There seems to be much difference of opinion regarding the use of more than one ground rod in a system. I'm not going to comment on that specific issue.
As far as I know ALL grounding conductors, including grounding rods, need to be tied together.
As far as I know ALL grounding conductors, including grounding rods, need to be tied together.
timselectric
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Yup
An additional (auxiliary) ground rod is not required nor recommended by most. But allowed (at the moment) by the NEC. But if installed it must also be connected to the main grounding system. And in no way replaces the required equipment grounding conductor.
Lighting protection is a completely different system.
Installed separately from the electrical system.
An additional (auxiliary) ground rod is not required nor recommended by most. But allowed (at the moment) by the NEC. But if installed it must also be connected to the main grounding system. And in no way replaces the required equipment grounding conductor.
Lighting protection is a completely different system.
Installed separately from the electrical system.
Durk_2007
New Member
Think of the ground system as a separate system than the power system, it keeps EVERYTHING connected to it at the same potential as the earth. No potential difference no shocky.
But if power were to short to ground you want ONE (1) path to complete the circuit back to the source (transformer or inverter) through the single neutral- ground bond.
But if power were to short to ground you want ONE (1) path to complete the circuit back to the source (transformer or inverter) through the single neutral- ground bond.
So what exactly does this mean about the lighting protection being different?
But the lightning protection system must still be tied to the GEC.
timselectric
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Absolutely not.
They are two completely different systems.
Lighting protection is installed around what you are trying to protect. With no contact (electrically) to anything but earth.
timselectric
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Lighting protection is a separate system from your electrical grounding system. They serve two different purposes.
Lighting protection is used to protect against a Lighting strike. (And static dissipation)
The electrical grounding system is used to protect people from electrical shock.
Yes and no. There is some wisdom in keeping them separate and for a long time they were. But the 2002 or so NEC required that if the lightning protection system is present, you have to connect your GEC to it.
timselectric
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There's no point in installing an expensive lighting protection system. And then connecting it to the system you are trying to protect.
That's like installing bullet proof glass , with a hole in it. And painting a target around the hole.
Bottom line is don't waste your money doing it wrong.
I'm just talking about code requirements. The code requires it and watchful inspectors will catch it.
timselectric
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This is why each jurisdiction is responsible for enforcing which parts of the NEC they choose to follow. And why the NEC is open to interpretation.
The NEC code board is made up of humans. And humans are known to make mistakes.
Many codes have been added in one edition. And removed in the next, for this reason.
Common sense and knowledge have to step in sometimes.
This part of the code (250.106) has existed for at least 20 years. It's also required by NFPA 780. The theory is that if the two systems aren't bonded together, the potential difference between them due to the impedance of the earth itself during a strike could result in side flashes and fires.
I don't know if it's true, I just know that the NEC requires my electrical installs to bond to any lightning protection system present and vice versa for the LPS installers.
timselectric
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If the lightning protection system is installed correctly. There will be no flash issues.
None of the jurisdictions I work in require them to be bonded together. Because it creates more problems than it solves.
Another code, regarding the auxiliary ground rod at out buildings is split in my jurisdictions. Some require it and some don't. If we install it for inspection. It's usually disconnected after.
We have a lot of lightning strikes in my area, in the spring.
And warranty work can kill a company.
Avoiding all gradient paths is almost impossible. But you do the best you can. And cross your fingers.
None of the jurisdictions I work in require them to be bonded together. Because it creates more problems than it solves.
Another code, regarding the auxiliary ground rod at out buildings is split in my jurisdictions. Some require it and some don't. If we install it for inspection. It's usually disconnected after.
We have a lot of lightning strikes in my area, in the spring.
And warranty work can kill a company.
Avoiding all gradient paths is almost impossible. But you do the best you can. And cross your fingers.
Rednecktek
Solar Wizard
OK, so to put things in an example for understanding, let me ask this:
Under NEC2020, which is what my state uses, if someone were to use a combiner box with lightning protection you would run a ground wire from the frames of the solar panels out on a ground mount back to the main distribution box for your system rather than a bar in the ground right at the panel mount, but you'd run a separate ground rod and wire from the lightning protection thinger in the box to its own rod in the ground?
Under NEC2020, which is what my state uses, if someone were to use a combiner box with lightning protection you would run a ground wire from the frames of the solar panels out on a ground mount back to the main distribution box for your system rather than a bar in the ground right at the panel mount, but you'd run a separate ground rod and wire from the lightning protection thinger in the box to its own rod in the ground?
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timselectric
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One ground wire for everything. Ran back to main grounding system.OK, so to put things in an example for understanding, let me ask this:
Under NEC2020, which is what my state uses, if someone were to use a combiner box with lightning protection you would run a ground wire from the frames of the solar panels out on a ground mount back to the main distribution box for your system rather than a bar in the ground right at the panel mount, but you'd run a separate ground rod and wire from the lightning protection thinger in the box to its own rod in the ground?
That's a surge protection device. It will help protect against a lightning gradient pulse. But not exactly lightning protection. (As in a direct strike)
You would ideally tie the arrestor ground to the grounding electrode that the equipment ground of the rest of your electronics was bonded to. This is so your clamping voltage is relative to the lowest voltage point you care about.OK, so to put things in an example for understanding, let me ask this:
Under NEC2020, which is what my state uses, if someone were to use a combiner box with lightning protection you would run a ground wire from the frames of the solar panels out on a ground mount back to the main distribution box for your system rather than a bar in the ground right at the panel mount, but you'd run a separate ground rod and wire from the lightning protection thinger in the box to its own rod in the ground?
If you ground the arrestor to your local rack ground, then a strike may raise the voltage everywhere simultaneously, keeping the arrestor from clamping due to the small difference in relative potential.
timselectric
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As a side note.
A surge protection device is a good thing to have.
It's more important to be at the equipment side of the run. Or can have one on each end.
A surge protection device is a good thing to have.
It's more important to be at the equipment side of the run. Or can have one on each end.
I try to put as many SPDs as the customer will pay for. Service entrance, panel, subpanel(s), air conditioner disconnects, yard lights, etc.
timselectric
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