Connecting Solar System Ground To House's Ground Rods?

[rs14smith]

Hi,

I have a small off grid solar system (little over 550 Watts), and i need to ground the system. The solar system (panels, charge controller, inverter, batteries) are located less than 15 feet from my house's ground rods. I've seen some people install a separate ground for some solar systems, but I was wondering if I can simply wire my solar system's ground to the house rods that already exist?

Hope that makes sense what I'm asking.

Thanks!

[organic farmer]

The Photo-Voltaic panels being outside are subject to lightning strikes. They need to be grounded separately. The wiring coming off them needs to combine in an electrical panel box, with a breaker, and that box needs to have a lightning arrester, or Surge Protection Device installed.

Do not try to use the house ground for this. As you will be leading lightning strikes into your house wiring. Lead them away from your house.

Wherever you put your Charge-Controller, Inverter, and Battery-Bank, should also be grounded, as a separate ground.

[rs14smith]

The Photo-Voltaic panels being outside are subject to lightning strikes. They need to be grounded separately. The wiring coming off them needs to combine in an electrical panel box, with a breaker, and that box needs to have a lightning arrester, or Surge Protection Device installed.

Do not try to use the house ground for this. As you will be leading lightning strikes into your house wiring. Lead them away from your house.

Wherever you put your Charge-Controller, Inverter, and Battery-Bank, should also be grounded, as a separate ground.

So, are you saying the solar panels need a separate ground and the charge controller, etc. need a separate ground as well?

Basically, 3 different grounds (house, solar panels, charge controller/inverter/battery-bank)?
Or can the solar panels be hooked to the same ground the charge controller, batteries, etc. are hooked to?

Lastly, some people use 2 ground rods with a minimum distance of 6ft between them. Is it required to use 2 rods?

[sensij]

Grounding requirements will depend on the system voltage, along with the type of charge controller and inverter. Good practice is to sink a dedicated electrode for the grounding, and bond it to your house ground. Different cycles of NEC code may have more or less specific requirements.

[rs14smith]

Grounding requirements will depend on the system voltage, along with the type of charge controller and inverter. Good practice is to sink a dedicated electrode for the grounding, and bond it to your house ground. Different cycles of NEC code may have more or less specific requirements.

But organic farmer just said you aren't suppose to use your house ground in any way? I'm a bit confused. Using my house fuse would be the simplest route, but I don't want to cause issues to my house electronics if a lighting strike was to hit my solar system.

[sensij]

It is a free forum, with free advice, and you get what you pay for. If you get conflicting advice, you'll have to find another source of information. I'd recommend the NEC as a starting point.

The ground rod pair with more than 6 ft between them is an NEC construct to get lower impedance to earth. Testing a single rod to make sure it is less than 25 ohm requires equipment you won't find at Home Depot, so sinking two rods to be sure is an inexpensive way to improve the odds that the ground will perform as it should if it is needed.

[rs14smith]

It is a free forum, with free advice, and you get what you pay for. If you get conflicting advice, you'll have to find another source of information. I'd recommend the NEC as a starting point.

The ground rod pair with more than 6 ft between them is an NEC construct to get lower impedance to earth. Testing a single rod to make sure it is less than 25 ohm requires equipment you won't find at Home Depot, so sinking two rods to be sure is an inexpensive way to improve the odds that the ground will perform as it should if it is needed.

Yes I know it's a free forum, but it's also ok to say you're confused as well lol. I've read some of the NEC requirements about this, but somewhat just glanced over it. Is there a section that relates to rather or not you can hook to your house ground? I think honestly just for safety, I'll just install my own 2 separate ground rods. However, I just need to confirm that "all" my solar equipment can use that same ground (solar panel frames, charge controller, inverted, batteries, the whole nine yards)?

[sensij]

Installing separate ground rods may not necessarily be the safest approach. You would need to share more information about your setup to get good advice (but even then it isn't assured). Panels, How they are wired, charge controller model, inverter model. The fact you have a house ground suggests more of a hybrid system than off grid, which also could complicate it.

NEC 690.47 may be what you want.

[organic farmer]

So, are you saying the solar panels need a separate ground and the charge controller, etc. need a separate ground as well?

I am in an area where lightning strikes are common.

Solar panels being outside, along with all of their wiring, are highly susceptible to voltage surges here. So here, it is recommended that all components that are subject to lightning strikes, have their own ground and
Surge Protection Devices.

As to the Charge-Controller, where is it? If it is outside and subject to lightning strikes, then, ....

Mine is not outside because I did not want to contend with heating the Battery-Bank structure. An entirely separate heating system was more than what I wanted to deal with.

[rs14smith]

I am in an area where lightning strikes are common.

Solar panels being outside, along with all of their wiring, are highly susceptible to voltage surges here. So here, it is recommended that all components that are subject to lightning strikes, have their own ground and
Surge Protection Devices.

As to the Charge-Controller, where is it? If it is outside and subject to lightning strikes, then, ....

Mine is not outside because I did not want to contend with heating the Battery-Bank structure. An entirely separate heating system was more than what I wanted to deal with.

My charge controller, battery bank, inverter etc. are inside my garage. I too did not want to have to deal with the heating system etc. So do you still have those grounded, or did you not ground your CC, inverter, etc?

Thanks

[organic farmer]

But organic farmer just said you aren't suppose to use your house ground in any way? I'm a bit confused.

Having all grounds bonded does not hurt anything. I am connected to grid, so I can get grid power on days when the grid is up. That power-pole has it's own ground rod, and there is a ground wire that leads to my house [along with the power wires]. It is connected to my house ground, where there are separate ground rods. It is okay for separate ground rods to be connected.

Wherever you expect to see a lightning strike happen, you want a ground rod local to be spot, to provide the surge the nearest path to ground as possible.

... I don't want to cause issues to my house electronics if a lighting strike was to hit my solar system.

I agree.

Wires from my solar panels lead into a combiner box. That box has breakers for each string of panels, that box has a Surge Protection Device [SPD], and that box has it's own set of ground rods.

Ideally strikes that happen there will be lead to ground at the nearest location [out there], rather than being led toward my house.

[organic farmer]

My charge controller, battery bank, inverter etc. are inside my garage. I too did not want to have to deal with the heating system etc. So do you still have those grounded, or did you not ground your CC, inverter, etc?

Thanks

The wiring diagrams / instructions for my Charge-Controller / Inverter / panel call for these devices it to be grounded.

It is grounded.

The panel that my Charge-Controller and Inverter fit onto also has 3 SPDs. Every SPD must be connected to ground.



Our neighbors here have dealt with grid outages ever since grid power was brought into this town. Some homes have never connected to grid so they have never became addicted to electricity. Among the homes that generate electricity for themselves, I know at least one of them has destroyed a battery-bank because the batteries were allowed to freeze once. It might not be as much of an issue down South though.

[Sunking]

They need to be grounded separately.

You have no idea what you are talking about and should not be giving anyone advice. What you advocate is extremely dangerous and does not comply with any known electrical codes, standards, or regulations. You advice can literally kill someone. What you do at your home is your problem and no one cares if you get yourself killed or burn down your home, but you have no business giving anyone else hurt. You can be held liable for such poor advice.

[organic farmer]

You have no idea what you are talking about and should not be giving anyone advice. What you advocate is extremely dangerous and does not comply with any known electrical codes, standards, or regulations. You advice can literally kill someone. What you do at your home is your problem and no one cares if you get yourself killed or burn down your home, but you have no business giving anyone else hurt. You can be held liable for such poor advice.

The wiring diagrams and instructions for my Combiner-box / Charge-Controller / Inverter / panel call for these devices it to be grounded.

[russ]

This is one reason DIY gets tricky and dangerous.

Reading a page out of NEC and applying it may be the wrong page.