system grounding questions

http://photovoltaics.sandia.gov/docs/PDF/CodeCorner94.pdf

As you scroll down through the above article, you will see a wiring scheme that shows the EGC (equipment grounding conductor) from the PV array is bonded to Earth but, is not bonded to the negative output of the PV array at the combiner boxes, nor is the EGC bonded to negative at the battery bank.
 However, if you look at the EGC at the vdc input to the inverter it is bonded to the neutral conductor as well as Earth.
As well, the EGC is bonded to the neutral conductor at the main breaker panel, which is also bonded to Earth.

I would like to point out though, that this scheme is dated 2003. The NEC (National Electrical Code) makes changes and is revised every three years. The lastest set of codes starts with this years (2008) new code book.
http://www.nfpa.org/catalog/product.asp?pid=7008SB&order_src=A291

Reading the article, you will find out that the PV array was going to be installed on the rooftop of the dwelling. If this had been done, there would need to be a GFP (Ground Fault Protection) breaker installed in the PV source circuit as well. For more on this and other code compliant PV system information, go to - http://photovoltaics.sandia.gov/docs/John_Wiles_Code_Corner.htm

truer words have not been spoken.  grounding baffles many, don't feel bad.

here is another link, and for a dc system, you would likely pull from your equipment grounding busbar to you grounding electrode conductor to your grounding electrode (ground rod).  in your small system, that would probably mean after you have grounded the modules and rails with the bare copper into the combiner, you would pull a positive, negative and ground into the dc load center.  there other necessary grounding conductors (controllers, enclosures) would meet on the equipment grounding busbar.  depending on where the modules are (on building or not on building for GFP) you may have to bond the negative and grounding conductors in the gfp, OR have to bond the two busbars with a bonding jumper.

perhaps that is helpful, hopefully i did not make it worse.

http://howto.altenergystore.com/Reference-Materials/National-Electric-Code-and-Solar-Electric-Systems/a45/

james
altE staff