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Why is grounding so HArrrd!!!

Maybe some lightning wise person can comment on something I read years ago. That the lightning protection aerials and the system in general is not to get hit by lightning to protect the house, but rather to 'drain' off the electrical potential in the air surrounding a structure so that lightning is less likely to occur there. If you think about it, if that aerial got hit by lightning it would likely vaporize that rod, and the braided wire all the way to the ground.

Any experts out there?
 
Philip53 said:
Maybe some lightning wise person can comment on something I read years ago. That the lightning protection aerials and the system in general is not to get hit by lightning to protect the house, but rather to 'drain' off the electrical potential in the air surrounding a structure so that lightning is less likely to occur there. If you think about it, if that aerial got hit by lightning it would likely vaporize that rod, and the braided wire all the way to the ground.

Any experts out there?
Click to expand...
This is what I was taught.
The point helps to equalize the voltage imbalance of the capacitance of the storm
 
Philip53 said:
Maybe some lightning wise person can comment on something I read years ago. That the lightning protection aerials and the system in general is not to get hit by lightning to protect the house, but rather to 'drain' off the electrical potential in the air surrounding a structure so that lightning is less likely to occur there. If you think about it, if that aerial got hit by lightning it would likely vaporize that rod, and the braided wire all the way to the ground.

Any experts out there?
Click to expand...
Not me but on the 'vaporization' theme. . .

I had a 3ft monopole fiberglass aerial serving wifi to my neighborhood. Connected to a 2.4ghz linear amp in a closet, LMR400 cable about 30 feet. to the closet with the equipment. LMR400 is a little bigger than RG-8, center conductor is FAT, but nothing like a braid. When it came into the attic the cable curled into an & shape/dragonfly wing, the tip was laying against the foam sheathing before proceeding thru the attic to the wiring closet. The other side of the sheathing had metal screening then stucco.

Lighting hit the aerial, it exploded. At the tip of the dragonfly wing the cable exploded and blew a baseball sized hole in the wall. I found fiberglass fragments of the antenna 1/4 mile away. Pretty much ruined all the equipment in the closet. I'm not sure that little loop might not have keep the stuff in there from actually exploding.

I think it matters that the paths are as straight as possible from the attracter to ground. I actually had enough excess cable to just cut it where it blew and put on a new end, and keep chugging. A few months later I went to a POE arrangement with a custom box/AP under the eave.
 
In Africa, those grass huts with dirt floors have killed/injured many people due to nearby lightning strikes. What I have read is that they will dig a trench around the hut & bury a copper cable, and probably put down a ground rod or two as well. This has met with great success, I have read.

I recently built a small garage about 75' from my house. I put a third solar array on the roof, with a combiner/disconnect on the rear wall of the building. I did add another ground rod next to this disconnect. The solar panels and the disconnect were connected to this ground rod, and this additional ground rod was connected directly by a separate cable to the pair of existing interconnected ground rods near the main house panels. All three of the ground rods are connected to each other.
 
ksmithaz1 said:
Not me but on the 'vaporization' theme. . .

I had a 3ft monopole fiberglass aerial serving wifi to my neighborhood. Connected to a 2.4ghz linear amp in a closet, LMR400 cable about 30 feet. to the closet with the equipment. LMR400 is a little bigger than RG-8, center conductor is FAT, but nothing like a braid. When it came into the attic the cable curled into an & shape/dragonfly wing, the tip was laying against the foam sheathing before proceeding thru the attic to the wiring closet. The other side of the sheathing had metal screening then stucco.

Lighting hit the aerial, it exploded. At the tip of the dragonfly wing the cable exploded and blew a baseball sized hole in the wall. I found fiberglass fragments of the antenna 1/4 mile away. Pretty much ruined all the equipment in the closet. I'm not sure that little loop might not have keep the stuff in there from actually exploding.

I think it matters that the paths are as straight as possible from the attracter to ground. I actually had enough excess cable to just cut it where it blew and put on a new end, and keep chugging. A few months later I went to a POE arrangement with a custom box/AP under the eave.
Click to expand...
I have had 5 lightning events in my life ….some killed people , some killed animals , some just keeps knocking out my internet gear and one burnt down our large family home on the coast…some hit sailboats in my marina and killed half the occupants. I have seen two of the strikes occur…
IIRC within the last few months a lightning bolt hit a falcon 9 rocket on te pad in Fla getting ready to launch and the mission was scrubbed…I don’t know all the details..
( and look at the expensive and elaborate lightning protection of the NASA launch pad ) ..

I really don’t know if lightning cares at all what we do, or don’t do … it just does what it wishes when it wants to do it…and ya can’t even sue it…

I just know, at some point , when I get my system totally finished out and working perfect and need nothing else , lightning will come and take it out…

it’s the way life works ..
J.
 
Philip53 said:
Maybe some lightning wise person can comment on something I read years ago. That the lightning protection aerials and the system in general is not to get hit by lightning to protect the house, but rather to 'drain' off the electrical potential in the air surrounding a structure so that lightning is less likely to occur there. If you think about it, if that aerial got hit by lightning it would likely vaporize that rod, and the braided wire all the way to the ground.

Any experts out there?
Click to expand...
It's actually both. It dissipates the charge to lesson the chance of a direct hit. And if there is a direct hit, it channels it around the building. Instead of through the building.
It does self destruct in the process. But that's expected.
You can't stop lightning. You can only attempt to avoid and redirect it.
 
My error… it wasnt a falcon 9 ..it was a falcon heavy…in April….Yeow…
 
timselectric said:
I would install a ground bar close to the inverter and charge controller. Connect this bar to the existing grounding system. And connect everything else to the bar.
Click to expand...
piggybacking on this as my situation is similar:
solar array to shed with charge controller and inverter. charge controller and inverter do not have ground locations.
Do I have this correct: I connect lugs and #6 ground wire to all panels, run it along with the pv wires to shed, install a ground bar in shed that #6 wire connects to, use mounting screws for charge controller and inverter as equipment ground to the ground bar, then run #6 ground wire all the way across my property to the opposite side of the house to connect to the existing ground rod at the main panel?
 
Liam M said:
Do I have this correct: I connect lugs and #6 ground wire to all panels, run it along with the pv wires to shed, install a ground bar in shed that #6 wire connects to,
Click to expand...
That's fine
for the exposed part, a minimum of #6 is required.
If it is ran inside conduit it probably doesn't need to be #6. Just sized appropriately for the circuit.
Liam M said:
use mounting screws for charge controller and inverter as equipment ground to the ground bar,
Click to expand...
The mounting screws should never be used for a grounding connection. It must be a dedicated connection just for the purpose of grounding.
Liam M said:
then run #6 ground wire all the way across my property to the opposite side of the house to connect to the existing ground rod at the main panel?
Click to expand...
#6 is the minimum requirement for exposed (to physical damage) ground conductor?
Otherwise it's sized according to the circuit it's ran with.

It should be ran with the circuit conductors and connected to the grounding system at the same location as the circuit conductors.
 
timselectric said:
That's fine
for the exposed part, a minimum of #6 is required.
If it is ran inside conduit it probably doesn't need to be #6. Just sized appropriately for the circuit.

The mounting screws should never be used for a grounding connection. It must be a dedicated connection just for the purpose of grounding.

#6 is the minimum requirement for exposed (to physical damage) ground conductor?
Otherwise it's sized according to the circuit it's ran with.

It should be ran with the circuit conductors and connected to the grounding system at the same location as the circuit conductors.
Click to expand...
I see now, the manual for the charge controller states:
If grounding is required, please make sure to ground the device on the negative.

How would that work?

For the inverter, would I drill an additional hole and add ground screw for equipment ground?

Also, the inverter AC out shows open ground with receptacle tester. I’m guessing an equipment ground has no effect on that, please advise.
 
Liam M said:
the manual for the charge controller states:
If grounding is required, please make sure to ground the device on the negative.
Click to expand...
Do not ground the negative. Only the enclosure (if metal).
Liam M said:
For the inverter, would I drill an additional hole and add ground screw for equipment ground?
Click to expand...
You could, if it doesn't have any ground terminals.
I would be surprised if it doesn't.
What brand is it? Picture?
Liam M said:
Also, the inverter AC out shows open ground with receptacle tester. I’m guessing an equipment ground has no effect on that, please advise.
Click to expand...
That indicates that the tester is not seeing the N/G bond. Which means that there either isn't one or the receptacle is not connected to it.
 
Liam M said:
I see now, the manual for the charge controller states:
If grounding is required, please make sure to ground the device on the negative.

How would that work?

For the inverter, would I drill an additional hole and add ground screw for equipment ground?

Also, the inverter AC out shows open ground with receptacle tester. I’m guessing an equipment ground has no effect on that, please advise.
Click to expand...
On vehicle mounted systems, the negative dc path is bonded to the vehicle frame. With home equipment, there will be grounding terminals, no additional dc bonding is required.
 
timselectric said:
Do not ground the negative. Only the enclosure (if metal).

You could, if it doesn't have any ground terminals.
I would be surprised if it doesn't.
What brand is it? Picture?

That indicates that the tester is not seeing the N/G bond. Which means that there either isn't one or the receptacle is not connected to it.
Click to expand...
inverter
I messaged the company asking about grounding and they sent me this photo:ground.jpg
Manual doesn’t mention grounding, I assumed this was just for wiring the 30a AC out, but are they saying this is for equipment ground as well?

charge controller
The mount is the aluminum heat sink at rear. I see now there are 2 mounting holes I’m not using, so I could add a ground lug at one of them for equipment ground?

Also, as this is not connected to house power, could you confirm whether I still should run ground from array to shed where components are mounted, then from shed all the way to the other side of the property/house where main panel is, or - add a ground rod at shed and earth ground there?
Thanks for all the help
 
Supervstech said:
On vehicle mounted systems, the negative dc path is bonded to the vehicle frame. With home equipment, there will be grounding terminals, no additional dc bonding is required.
Click to expand...
No grounding terminal, but I have an extra mounting hole I can add a grounding lug to.
 
Liam M said:
Manual doesn’t mention grounding, I assumed this was just for wiring the 30a AC out, but are they saying this is for equipment ground as well?
Click to expand...
That is the equipment ground connection terminal.
 
Liam M said:
The mount is the aluminum heat sink at rear. I see now there are 2 mounting holes I’m not using, so I could add a ground lug at one of them for equipment ground?
Click to expand...
Yes, that's fine.
Liam M said:
Also, as this is not connected to house power, could you confirm whether I still should run ground from array to shed where components are mounted, then from shed all the way to the other side of the property/house where main panel is, or - add a ground rod at shed and earth ground there?
Thanks for all the help
Click to expand...
If it has wiring running to the house. Then it should be connected to the same grounding system.
If not, then they can be separate.

Also from the notes on the picture. There's definitely not a N/G bond provided by the inverter.
I would recommend that you check with the seller. And make sure that it is capable of being bonded externally. Some of the less expensive inverters are not isolated between the DC and AC side. And can be damaged if bonded and negative grounded. (Usually only a problem for mobile applications)
 
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