need help with house ground

[oldcat]

hey you all.... need some help.. just a little confused.... if i put a seperated ground rod for my inverter and charge controller and batterys... it all in my house.. batterys are out side.... . if my inverter is hook in to my house power for the charger.. do i need to hook it all in to my house ground rod or can i leave it seperated from the house ground rod

 

[svetz]

Not an electrician and your local codes could be different, but AFAIK all grounding rods always need to be tied together because none are ever at the same potential. I know you didn't mention panels, but you might find something in here: Grounding PV

 

[oldcat]

yes grounding panels to when i get thim........... can i ground all the AC and DC equipment on the same earth grounding rod? or do they need to be grounded apart? this is what i need to no.....thanks

 

[svetz]

Not an electrician but AFAIK, all the grounding should be tied together. In AC neutral is the return path for current. DC is a two wire system and negative is often bonded to ground. The ground path for both is to provide a safety for shorts and a way for transient and static charges to bleed out.

This might help out: https://www.solar-electric.com/lib/wind-sun/PV-Ground.pdf

Interesting you said "DC equipment" rather than "panels"... I also found this ref:

... customers have reported damage to inverters, charge controllers, DC refrigerators, fluorescent light ballasts, TVs, pumps, and (rarely) photovoltaic panels. ... and ALL reports were from owner-installed systems that were NOT GROUNDED.

So, perhaps having a ground path for all DC equipment is important.

 

[Kep]

I grounded all my equipment (DC and AC) individually on both 8' copper coated ground rods and Ufer ground bars encased in concrete used to mount equipment and buildings and then tied them all together. Lightening can't see your equipment if it is all earth grounded together. It is not a guarantee but reduces your risk. I do not believe in lightning rods as they attract lightning and try to divert it to earth ground useually failing to protect your equipment.

 

[oldcat]

ok then so i put the (ACandDC) all on the same ground if you use a 2 ground rods . and tie it to the house ground..

 

[Kep]

Updated post to be more clear.

I grounded all my equipment (DC and AC) individually... and then tied them all together. Yes you can tie it to the house ground too but it is not required. The house can be earth grounded separately.

Your power and ground supplied to the home will tie the earth grounds together even though the earth ground is only tied indirectly through the power supply to the home.

The Ufer Ground is an electrical earth grounding method developed during World War II. It uses a concrete-encased electrode to improve grounding in dry areas. The technique is used in construction of concrete foundations. A 20' stick of #4 rebar encased in your concrete foundation is all you need to clamp your ground to.

 

[svetz]

ok then so i put the (ACandDC) all on the same ground if you use a 2 ground rods . and tie it to the house ground..

NEC allows that, but watch this video. Apparently multiple grounds are bad.
Not that there's much you can do about it. Once you've put posts into the earth and hooked panels to it, you've got a second ground regardless.

If it's all on your roof (and not a ground mounted system away from the house) after seeing the video I would not use a second ground for anything if I could help it.

 

[Supervstech]

Updated post to be more clear.

I grounded all my equipment (DC and AC) individually... and then tied them all together. Yes you can tie it to the house ground too but it is not required. The house can be earth grounded separately.

Your power and ground supplied to the home will tie the earth grounds together even though the earth ground is only tied indirectly through the power supply to the home.

The Ufer Ground is an electrical earth grounding method developed during World War II. It uses a concrete-encased electrode to improve grounding in dry areas. The technique is used in construction of concrete foundations. A 20' stick of #4 rebar encased in your concrete foundation is all you need to clamp you ground to.

If the inverter has a ground system, and it is tied to the house electrical, the grounds need to be bonded together.
Getting shocked by the earth really sucks. Avoid it at all costs.

 

[oldcat]

yea i watched it it good . but i cant see hooking up my panels and DC to my house ground look like it would cause more problems on the house ground rod..i have not hooked nothig up yet ...

 

[Supervstech]

I grounded all my equipment (DC and AC) individually on both 8' copper coated ground rods and Ufer ground bars encased in concrete used to mount equipment and buildings and then tied them all together. Lightening can't see your equipment if it is all earth grounded together. It is not a guarantee but reduces your risk. I do not believe in lightning rods as they attract lightning and try to divert it to earth ground useually failing to protect your equipment.

Lightning rods do not attract lightning.
They dissipate the positive electrons from the earth into the atmosphere to prevent lightning from striking the rod protected area.
Lightning rods are a good idea... they do not promote strikes they prevent them.

 

[Kep]

I watched the video and he is not talking about an application such like ours. My solar array is 10' away from my solar power shed and ground mounted. My home is about 100' away from my power center and solar array. My home is grounded independently. So are my solar array and solar shed. All my grounds are to code. I tied or bonded the solar shed and array together again per code. This effectively makes the two structures grounded on one conductor buried at two points. Thus there is no difference in potential between the structures. Lightning typically strikes something that has a different potential than the ground around it but is close enough to provide a path to ground for lightning to connect (IE: tree, light pole, people etc).

My Ufer grounds for the DC system are in both the solar array anchor pad as is the solar shed. I then tied the two together to complete the DC system grounding effectively one ground loop like at power substations. For grounding of the AC and home it is done with a Ufer ground in the foundation of the home. The AC conductors from the solar shed to the home is along with the AC neutral and is buried inside a conduit. My lightning arrestors are all connected to the DC grounding system.

So what I'm saying is the DC grounds are bonded together per code so the path is provided for things to pass through to ground but not through equipment to ground. Had I not bonded them together a path from one structure to the other would be done through the DC and PV wires. The DC input and AC output are effectively isolated from one another except for the lightning arrestor.

 

[Kep]

They make themselves the most likely to be hit if lightning is trying to arc to ground in that location. This is why I want my equipment to be grounded or the same potential as the earth around it. I live on a mountain so I researched grounding and lightning extensively before beginning to build up there. I do not want to increase the potential that lightning would strike anywhere near my solar equipment. This is why I don't want or like lightning rods. What I did find out is there are many things about lightning we still do not understand. I took what we seem to know and applied it the best that I could.

Quote: The one thing lightning rods do are increase the probability of creating a streamer, which increases the odds that it will make contact with the last step leader. If the streamer is successful in making contact with that last step leader, it will direct the electric current into the ground.

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[RandyP]

NEC allows that, but watch this video. Apparently multiple grounds are bad.
Not that there's much you can do about it. Once you've put posts into the earth and hooked panels to it, you've got a second ground regardless.

If it's all on your roof (and not a ground mounted system away from the house) after seeing the video I would not use a second ground for anything if I could help it.

Svetz,
Your link took me to Mike Holtz YouTube Videos re: grounding. The best explination of equipment grounding, grounding electrodes, grounding electrical electrode conductors I have seen lately. Well worth the time to view and digest. Thank You.
Will, if you want to understand the requirement for grounding iaw the NEC, this and other grounding videos by mike Holtz are excellent.

 

[svetz]

Svetz,
Your link ...

Credit where it's due... I saw it first from James12345 - thanks again James!

 

[RandyP]

Credit where it's due... I saw it first from James12345 - thanks again James!

If that is the case, I stand at attention and salute James12345 for sharing this link.

 

[Kep]

My grounds are like this. The two Ufer grounds are connected together under ground. The ground rod just provides a way to attach clamps for grounding additional components. So like I said it is one continuous ground with a way to attach to it at both the solar array and the solar shed.

 

[b.james]

Don't see that it's going to do much good in that hard dry ground . Is it normally like that? I'd make sure that's where I piddled , but not in a lightning storm.

 

[Kep]

Don't see that it's going to do much good in that hard dry ground . Is it normally like that? I'd make sure that's where I piddled , but not in a lightning storm.

It is a Ufer ground so it is all encased in concrete and that is the preferred method used for dry arid climates like Arizona.

 

[Deleted member 783]

It is a Ufer ground so it is all encased in concrete and that is the preferred method used for dry arid climates like Arizona.

Grrrrr guess I need to re-do mine.