DC grounding ?

verdigo

I am in assembling the DC portion of my system. My grounding plan is to run all grounds, ie combiner chassis, Classic 150, and Battery bank to the E-panel grounding bus bar, and in turn grounding that to the grounding rod. I have read here on the forum in the past that it is better not to have multiple paths to ground. I was planning to run the PV array directly to the ground rod though. Am I understanding this correctly?

Thanks

Dennis

BB.

Re: DC grounding ?

verdigo wrote: »

I am in assembling the DC portion of my system. My grounding plan is to run all grounds, ie combiner chassis, Classic 150, and Battery bank to the E-panel grounding bus bar, and in turn grounding that to the grounding rod. I have read here on the forum in the past that it is better not to have multiple paths to ground. I was planning to run the PV array directly to the ground rod though. Am I understanding this correctly?]

Grounding the PV Array to a local ground rod (and mounting structure)--GOOD.

Grounding the negative (or positive) PV power connections to a remote/local/any ground--Can be a big problem (depending on lots of stuff) and almost never recommended.

Running a 6 AWG wire from the remote ground rod to the local/main home ground rod--I usually recommend YES.

-Bill

verdigo

Re: DC grounding ?

I guess I should clarify. The array frames and mounting rails are going directly to the ground rod. The positive and negative leads from the individual strings go to the positive bus for the circuit breakers and the negative bus bar in the combiner. The PV negative "in" and the chassis ground in the Classic are one in the same though it does have a PV neg "in". The combiner and the Classic's chassis's are grounded to the ground bus in the E-panel, which in turn is grounded to the ground rod.

Don't know if that is clarified or not.

Dennis

BB.

Re: DC grounding ?

Grounding the array negative/battery negative in the E-panel is standard (and fine).

Note, there can be a requirement for DC GFI protection... Typically a 1 amp fuse/breaker between Battery Negative and Safety Ground... If the fuse/breaker blows, the solar array/charge controller will shut down (either through MPPT controller electronic detection of blown fuse or through a ganged breaker between 1 amp breaker and 1 or 2 more breakers on the PV+ (and sometimes PV-) lines. This type of fusing of battery negative to safety ground is something I oppose--but current code permits or may even require in some cases.

If you have a strong potential for lightning strikes, it may be worth installing Lightning Arrestors at the PV Array Combiner and in (possibly) other locations (and on the AC Inverter Output).

Midnite makes some relatively "high tech/modern" lightning arrestors.

-Bill

verdigo

Re: DC grounding ?

Thank you Bill. I suppose what I have rigged up right now will suffice. I am definitely going for lightning arrestors.

Thanks again.

vtmaps

Re: DC grounding ?

BB. wrote: »

Grounding the negative (or positive) PV power connections to a remote/local/any ground--Can be a big problem (depending on lots of stuff) and almost never recommended.

Depends on the charge controller... some controllers ground the PV array internally... But you know that:

BB. wrote: »

Grounding the array negative/battery negative in the E-panel is standard (and fine).

--vtMaps