Off grid lightening protection

[jerrygar]

We recently had a massive electrical storm. I know of two house fires, four telephones blown off walls, one stove receptacle blown off a wall, one automobile tire flattened, one destroyed charge controller and three destroyed inverters and numerous grid failures. That is probably only a small percentage of the damage.

I am now installing a small (8 175 watt panel) off grid system (there are many in this area.) What is the best lightening protection?

Based on what seems to be current best practice, I plan to:

Install 3 ground rods spaced 10' apart (we have no soil, only lava rock, so the connection to ground is bad.)
Bond the solar panels and connect to the rods with #6
Connect the charge controller to the rods with #6.
Connect the negative side of the batteries to the rods with #6.
Bond the charge controller, inverter and other metal parts with #6.
Connect the 110 v. distribution panel to the rods with #6.
Bond the hot and neutral in the distribution panel.
Install lightening ancestors on both the AC and DC sides.
Connect the telephone ground to the ground rods.

Comments or suggestions?
Thanks,
Jerry

 

[Cold Fusion]

I'd probably with reading NFPA 780.

cf

 

[SG-1]

Any metal underground metal waterpipes or well casings or a septic system ?

 

[hurk27]

The problem with off grid systems is the lack of a 0 point reference with earth, which we have with common utility supplied systems, other problems can be attributed to both systems when done improperly, such as multi-point entrance to structures, long bonding conductors, lack of equal point bonding.

Utility systems are referenced to earth at every transformer, and usually every ? mile of transmission line ran, but off grid it's next to imposable to achieve this in the foot print of a single dwelling since there is just not enough land mass. so the next best thing would be to try to bring all equipment to the same potential by a common bonding grid, and entrance to each structure at a single point through a RF choke such as a grounded brass plate with an opening large enough to pass all the conductors, other metallic penetrations into the structure such as water/gas pipes should also pass through this same plate, with all bonding done to this plate as a single point for this structure and any other structures common to the same property.

Since you mention that you have no soil and are dealing with lava rock, which I'm not experienced with, the only thing that I could think of for getting a good connection to bond to the lava would be some kind of concrete embedded electrode with the concrete poured directly in contact with the lava, I have heard that this works when rock is encountered, but more research should be done as to what would be the best way to get a good bond to the lava.

Keep in mind that lightning is a high frequency event, and long runs in grounding and bonding can act like an open circuit, also conductors with a larger surface area such as braided flat copper conductors will give you a lower impedance to this higher frequency of lightning.

But all in all contacting a UL certified lightning specialist would be the right thing to do since this is out of the realm of most electrical contractors.

 

[don_resqcapt19]

Most if not all of the damage in the OP likely came from strikes to or near the power and phone that serve the structure. A stand alone system is not likely to suffer the same damage and the use of lighting protection may not be needed.