DC grounding in a Schneider system

[bsr]

Please see the schematic of the system I am wiring up. This is from the installation manual of Conext™ XW Pro. I have couple of questions regarding DC grounding.

1. The AC side is grounded through the utility. (top ground bus bar in the PDP). It doesn't show explicit grounding for DC side. Do I have to run a wire from DC grounding bus bar of PDP to grounding rod?

2. Schneider Conext MPPT 100 compatible with either negative grounded, positive-grounded, or ungrounded (floating) PV arrays. From reading many posts, I see negative grounded system are most common, and recommended. I do have my solar panels (frames) connected to a ground wire and can bring to the charge controller or connect to a rod directly. Should I ground the panels and keep the pv/charge controller floating, or should I bring the panel ground cable to the charge controller and negative ground the DC side.


Thanks
bsr

 

[400bird]

I'm pretty sure it doesn't show DC grounds because floating for both PV and battery is common. For permitting, my city asked me to remove the DC grounds from the drawing.

 

[robbob2112]

DC/negative ground is for mobile systems - residental systems are left floating to allow the inverter/mppt to detect arcing out at the array. (arc-fault)

It used to be common to do negative ground on everything, but no more.

 

[bsr]

thank you so much for the response. I am reading the materials available on the resource section and check out arc-fault. thanks again

 

[robbob2112]

Arc fault detection can be a requirement for some AHJ if you are doing a roof install. Depends on if you need to interconnect agreement and what version NEC they are on.

If you are off-grid/outside a city, you may still be subject to state rules.