N-G Bond, Separated systems

[teal95]

My system continues to get more complicated. I have a grid supported SolArk 15k and am now adding 3 phase from 6500ex's. The SolArk has been operational since Christmas time, now I'm getting into the details of 3 phase. The 3 phase shares the batteries with the SolArk and will get some of the solar panels (currently 6 strings into the SolArk, but shading is causing some of the strings that are in parallel to not be optimal).

Does the 3 phase get it's own ground or do I tie it back to the split phase ground?

Does the neutral in the 3 phase get bonded to ground?

There's a trough under everything so connections are fairly easy regardless.

 

[timselectric]

One grounding system for everything.
You already have an existing grounding system. So everything new will connect to it.
As for the N/G bond, each separately derived system will need its own.
From the title, I'm assuming that there's no connections between the two systems?
(Other than grounding and batteries)

 

[teal95]

Correct, no connections other than battery and grounds. I had thought about connecting one of them to 110 (one leg off of breaker box fed by SolArk), but was told that I would need to hook up all 3 phase, which i don't have. I don't understand why it wouldn't work...

 

[timselectric]

Correct, no connections other than battery and grounds.

Then yes, the 3-phase system will need a N/G bond. (This might be provided by the inverters)

I had thought about connecting one of them to 110 (one leg off of breaker box fed by SolArk), but was told that I would need to hook up all 3 phase, which i don't have. I don't understand why it wouldn't work...

When they are stacked together, they operate as one system.
Feeding power into only one input would look like an error (partial power loss)to the system.

 

[teal95]

So, functionally, there is no reason for it to not work, except that it's probably been programmed to shut down as it would think it's lost 2 phases?

I have 4 of the invertors. My idea was if I could feed grid to 1 phase I would only need 1 more to effectively run at 13 kW/phase. I shouldn't need more than 1 but...

 

[timselectric]

So, functionally, there is no reason for it to not work, except that it's probably been programmed to shut down as it would think it's lost 2 phases?

Correct

I have 4 of the invertors. My idea was if I could feed grid to 1 phase I would only need 1 more to effectively run at 13 kW/phase. I shouldn't need more than 1 but...

I'm not sure if I understand this.
But, you can't blend one grid phase with two inverter created phases.