TalkBaja.com » Baja Mexico Forums » Off-Grid / Solar, Wind or Generator?

All the discussion about grounds on BajaGringo's "Combining wind turbines with solar" thread got me re-thinking my grounding and lightning practices, so I started doing more research and reading.

Ground Wiring:

Currently I'm using a single ground point for ALL my safety grounds. Everything, including AC and DC safety grounds from the outbuildings, solar components, and the satellite dish routes back to a ground buss in my main panel using #6 braided wire, then out to the ground rods. I do not have multiple ground points for each building or component. If I understand the theories correctly, It seems a lot of people agree that multiple ground points can create ground loops during a lightning strike, sending the charge back into sensitive electronics. One thing that does concern me about the method I'm using is that a lightning strike on an outbuilding does route back through my main panel before dissipating out to the ground rod, but I think I'll stick with it anyway. There seems to be a downside to just about every suggested grounding method.

At every point where lightning can enter the sensitive electronics of the system, I have surge protectors that will (should) shunt all lightning energy to the ground.

Since I can only go down 4' before hitting solid rock, I have two 4' ground rods bonded together with #6 wire. Then I have 20 feet of copper pipe buried horizontally, that is also bonded to the two ground rods with #6 wire. Right now my ground rods are in poor dry soil. I'm going to move my ground rods to a area that receives water regularly and use BajaGringo's method for re-sinking them.

I had planned to connect the battery negative to ground also, but was later advised not to do so as the bond between the battery negative and system ground can actually attract lightning. Which seems to be confirmed by some of the posts in the URL below. One thing I really never thought about is that you are only grounding the frame of the solar panels. The positive and negative from the actual cells are isolated from the frame, so as with the batteries, the negative from the panels floats and is not bonded to ground or the frame. Now I understand why bonding the battery negative to system ground can attract lightning.

Now I'll get to the point. I came across this interesting discussion about grounding the solar panels http://www.wind-sun.com/ForumVB/show...?t=4490&page=2. Read post #12, or the second one down on the page. The guy in this discussion seems VERY knowledgable and he believes the solar panel frames should not be grounded, and in fact doing so attracts lightning...BUT there's some compelling arguments against this method also.

What to do I'll probably wind up leaving my frames grounded. Hopefully no-one on this site finds out if their grounding method works against a lightning strike. Just one more theory to add to the confusion!

Wooo...

The grounding issue is something that has actually stalled me a bit before going forward with finishing my system upgrade. The more I read about grounding solar / off-grid systems the more I would find diverse opinions on the subject. I had already read the thread you quoted from the wind-sun.com forum and it was one that stuck in my mind when I posted earlier on some of my questions about grounding.

If the decision for grounding lightning outside my panel will only produce a ground loop at worst, I would rather remove the high voltage/current surge a strike would bring from my panel / equipment.

Minor ground loops can be dealt with by running your sensitive audio gear off an isolation transformer - which I do. I bought one when I moved to Baja years ago as I knew the CFE provided power was noisy and wanted to protect my gear.

I am starting to get a better feel now for the direction I will go but and going to do a bit more research, just to be sure. I really appreciate your input and hopefully we all come away from this a bit more informed...

How about a Ufer ground....might be perfect for those conditions.

Funny you mention that patch. I was actually considering the option of creating a Ufer ground for my wind turbine lightning protection. I have a bunch of extra 1" rebar left over and was thinking of laying it down near the bottom of a concrete filled trench, tied to my wind turbine pole via welding cable.

It does seem like a better option than directing a strike to ground via my panel....