Separate Grounding Rod For Tiny Solar System?

[rs14smith]

Ok, let me preface by saying, I know I should be check my local code, AHJ, what have you, but I'm hoping someone can simplify what I'm reading in the NEC (250.58) which I think is telling suggesting I have to use my houses grounding rod for my add-on 100W solar system that is only being used to power a garden water pump and some LED lights for my upper deck.

My Renogy aluminum framed solar panel is attached to the side of my house (wood fencing for my upper deck), but does not power anything "inside" my house (such as AC outlets, etc.) and never will. My houses grounding rod is about 35 feet away from where my solar panel is mounted on the wooden fence connected to my upper deck.

I originally thought I needed to just drive a separate grounding rod for my solar setup since the distance from my solar panel to my house grounding rod was so far and it would not be practical to run 6AWG bare copper wire 35 feet. But since my solar panel is attached to my house/building, I'm not sure how to interpret what I'm reading in the NEC.

Hopefully all this makes sense. Any help is appreciated.

 

[iamrich]

This is a DC voltage application, no? I don't think NEC 250.58 applies to DC. I wouldn't worry about it myself, but if you really want to ground the system, I would just drive another ground rod. You will not create a ground loop because the systems are completely separate.

 

[Supervstech]

I agree.
If this is a low voltage dc system, the panel ground is for lightning arresting only. A good metal rod, fence post,water pipe in the ground will suffice.

 

[newbostonconst]

I am a big NEC code person and in this instance I don't think I would worry about it either.....Call it temporary and standalone if ever asked.

 

[rs14smith]

This is a DC voltage application, no? I don't think NEC 250.58 applies to DC. I wouldn't worry about it myself, but if you really want to ground the system, I would just drive another ground rod. You will not create a ground loop because the systems are completely separate.

I agree.
If this is a low voltage dc system, the panel ground is for lightning arresting only. A good metal rod, fence post,water pipe in the ground will suffice.

I am a big NEC code person and in this instance I don't think I would worry about it either.....Call it temporary and standalone if ever asked.

Thanks for sharing your thoughts on this. What lead me to the 250.58 section is the 690.47 section of the NEC (version 2017) which part of it states the following that I feel my application may fall into:

(A) Buildings or Structures Supporting a PV Array. A building or structure supporting a PV array shall have a grounding electrode system installed in accordance with Part III of Article 250.
PV array equipment grounding conductors shall be connected to the grounding electrode system of the building or structure supporting the PV array in accordance with Part VII of Article 250. This connection shall be in addition to any other equipment grounding conductor requirements in 690.43 (C ).

 

[Supervstech]

That says the panels need to tie into the grounding system of the building the array is attached to...

 

[rs14smith]

That says the panels need to tie into the grounding system of the building the array is attached to...

Correct, so since my panel is attached to part of my house/building (it is attached to the deck that is attached to the house), I need to tie my panels to my house's grounding system which my beginner's brain is saying that would be the grounding bus bar or grounding rod.

Based on your response, I can tell I'm mis-understanding something or have a term/definition mixed up with something else. ?

 

[iamrich]

Ultimately the NEC is designed to make everything safer (while keeping in mind cost impact). Will you feel safer, and more to the point will you BE safer by grounding your system to the house ground? I can't answer the first part, but I do not see any way you actually will be safer.

 

[Supervstech]

The deck is attached to the house.
If the panels are attached to the house, they are a lightning attractor. Connecting to the house grounding system would be wise.
if there is a METAL water pipe closer to the panels, grounding to that would suffice. If you have plastic water pipes, that option would not work.
I would install a ground rod, and have a conductor tie that rod to the panels and your house ground rod system.
but... for a small solar panel only powering low voltage lights on the deck, and a small pump... the single ground rod should suffice.

 

[newbostonconst]

The deck is attached to the house.
If the panels are attached to the house, they are a lightning attractor. Connecting to the house grounding system would be wise.
if there is a METAL water pipe closer to the panels, grounding to that would suffice. If you have plastic water pipes, that option would not work.
I would install a ground rod, and have a conductor tie that rod to the panels and your house ground rod system.
but... for a small solar panel only powering low voltage lights on the deck, and a small pump... the single ground rod should suffice.

If there is a easier path for the lightning to travel it will....Tying your system into the ground conductor could direct the lightening right into your house wiring and make things worse.

 

[Supervstech]

If there is a easier path for the lightning to travel it will....Tying your system into the ground conductor could direct the lightening right into your house wiring and make things worse.

That isn’t how lightning works.
Lightning creates an imbalance, and generates field charges. If metal objects are grounded, the imbalance dissipates and prevents a strike. Also, the MAJORITY of lightning damage is from a ground or tree strike generating an em field that causes high voltage on the conductors...

 

[time2roll]

All metal items attached to a house are not grounded.

Roof flashing
Chimney spark arrester
Aluminum window frames
Basketball hoop

I think a single 12v panel not attached to the house electrical falls into the same catagory.

 

[rs14smith]

All metal items attached to a house are not grounded.

Roof flashing
Chimney spark arrester
Aluminum window frames
Basketball hoop

I think a single 12v panel not attached to the house electrical falls into the same catagory.

I must say, this is probably the best common sense answer I have found that may be related to my application. ?

 

[Supervstech]

All metal items attached to a house are not grounded.

Roof flashing
Chimney spark arrester
Aluminum window frames
Basketball hoop

I think a single 12v panel not attached to the house electrical falls into the same catagory.

None of those items have wires running long distance that can capture emf and cause a fire...