D/C Breakers before String-Inverter? Lightning Arrestors? How do you ground?

I'm somewhat confused by this subject and wanted to see what the general consensus was for PV Installations. On my solar system I have the railing grounded by #6 bare copper, the Panels themselves are grounded by Unirac's grounding mid-clamps.

#10 gauge wires from the panels run through conduit to the inverter, then the inverter is grounded via a 3-way w/ground A/C #10gauge cable that runs to an old style A/C no fuses/breakers disconnect to the meter-box.

The meter-box is grounded with a ground rod next to the power pole which is then connected to 60ft run buried w/o conduit (same #6AWG ground wire). to a copper ground rod that is sticking out a few inches of the concrete foundation and that is connected to the rebar..
This #6 runs up to the railing which it also grounds and then terminates.

The reason why I've grounded it this way is two years before I had solar a lightning strike hit about 500 ft. or so from the house near the power lines, it charged the lines destroyed the A/C Transformer and went into our house destroying electronics and making what sounded like a shotgun go off inside our breaker box.

Also the meter box had it's own set of breakers and was grounded to the one ground rod that came with the power pole. Clearly this wasn't enough, I'm hoping that between the ground rod 60ft of bare copper exposed to dirt and the faus ground. That this should give the electricity plenty of ample opportunity to go to ground and avoid my precious high $ equipment. I should also mention that I live where you have a few inches of dirt then often solid limestone/rock making grounding more difficult.

My weakest link I think would be the Inverter being fried by a lightning strike energizing my panels.. then all I'd have to depend on would be the #10 awg ground.

So what do you think I've seen a lot of people recommend lightning arrestors or a grounded combiner box w/ground AND Lightning Arrestor and then I've seen a lot of people say that it's not necessary.

On your roof installs what do you generally do for grounding?


  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Have you searched the forum for Lightning, grounding and surge protection or SPD...  there are some very long and detailed discussions that should answer all your questions. 
    Sorry I know just the basics of grounding, and that is you should only have all your AC & DC dist boxes on a single connection to one Ground point for your house and it the array is grounded , that ground point should be connected under ground to the house ground point with #6 ga bare copper wire... hth
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