Question about grounds and lightning

[MScott]

In the middle of a thunder storm right now and it reminded me of a question I have about grounds.
First of all, I have a completely off grid solar powered home so I have no wires (electric or phone) coming in to my house/garage. Last summer we had a severe thunder storm which knocked out one of my inverters as well as my TV and computer. The lightning strike was a large pine tree about 200 yards from my house which was actually set on fire. Nothing struck the house or solar panel array.
Consensus is that the lightning surge came into the electrical system through the ground rods since this is the only connection with outside (except for the panels.) I have been advised that the only way to avoid this in the future would be to remove the ground rods, but I am afraid to do this since it goes against everything I know about electrical systems and would surely not pass an electrical inspection.
Does anyone have any comments about this? Is there some kind of lightning arrestor that could be added to my system to protect it. (There was about $2000 damage done and even though it was covered by insurance, I don't really want to pay another $500 deductible.)

 

[kd3pc]

NOTHING will stop a direct hit, and the induced current it creates in nearby electrical systems.

Keep your grounds, as removing will them will do nothing but make your system unsafe. High current, low voltage systems need those grounds.

There is nothing to say that the strike did not jump from the tree directly to ANY better ground, be it a water pipe, ground rod, damper/denser soil that joined the foundation or even exposed wiring.

It is an induced current, many times...not a carried current via a specific path. In this case, close was good enough. There are various devices, none of which will sustain a direct hit and protect, available. Some work better than others, many are quite expensive. Again none are a sure thing.

Leave the rods

 

[Gooch]

NOTHING will stop a direct hit, and the induced current it creates in nearby electrical systems.

Keep your grounds, as removing will them will do nothing but make your system unsafe. High current, low voltage systems need those grounds.

There is nothing to say that the strike did not jump from the tree directly to ANY better ground, be it a water pipe, ground rod, damper/denser soil that joined the foundation or even exposed wiring.

It is an induced current, many times...not a carried current via a specific path. In this case, close was good enough. There are various devices, none of which will sustain a direct hit and protect, available. Some work better than others, many are quite expensive. Again none are a sure thing.

Leave the rods

agreed. nothing you can do about it. the amount of energy in a lightning strike is so high that it will take ALL available paths, not just the one of least resistance.

 

[JoeFin]

Consensus is that the lightning surge came into the electrical system through the ground rods since this is the only connection with outside (except for the panels.) I have been advised that the only way to avoid this in the future would be to remove the ground rods, but I am afraid to do this since it goes against everything I know about electrical systems and would surely not pass an electrical inspection.

That is what they do in electrical transmission power - and no it is not designed for personal safety.

The amount of joules of energy a lightening strike puts down you could have a garage full of MOVs and it would still not be enough. Putting your home on a floating delta or high impendence grounded transformer wouldn't satisfy the local code authorities either.

They do have lightening strike detectors that would sense any strikes at a given distance and alert you or automatically disconnect your system. This is probably the most feasible alternative.

Once the system is disconnected you would then want to short all conductors to ground to eliminate any possibility of electrical potential between them

 

[MScott]

Thanks. That was my thought too. Does it seem reasonable that a strike 200 yards away would travel that far through the ground. It was (AFAIK) the only close strike during the storm.

 

[JoeFin]

Does it seem reasonable that a strike 200 yards away would travel that far through the ground. It was (AFAIK) the only close strike during the storm.

Sure depending on the soil conditions as it radiates away from the original point of impact your solar array and home would have seen a difference in potential

 

[MScott]

OK, thanks guys. I knew I would get some good advice here. I guess I'll just leave things as they are. The probability of another close strike is probably very low anyway.
The soil here is rather shallow over Precambrian Shield rock but there is a low area with a stream between the strike and my house so the soil in that area would be deeper and wet.