Feedback on System Design - 17.6kW and 2 PW

[Eric33432]

Given this:


Then this is unnecessary, as the service neutral conductor is already earthed:


But this part is very important, as each service disconnect initiates its own EGC, and that EGC system needs to be bonded to the neutral to function properly:


Like any building with multiple services, the multiple EGC systems with multiple EGC-neutral bonds will allow neutral current on the EGCs if the different EGC systems ever become interconnected, as is not unlikely.



Given that you have 15.6 kW of inverter capacity, and currently hit at most a bit over 12 kW, you could increase the DC size by a 1/3 (add 12 more panels) without adding any inverters or having more than say 0.1% clipping losses for the year. And that's conservative for the case that all 37 or 49 panels are all facing the same direction; if you have multiple roof planes with multiple orientatoins, you could probably add more than that. [I did not review the thread, so perhaps info on the panel arrangement is already above.]

Cheers, Wayne

Thanks, Wayne, for this.

It appears that many electricians are weak on grounding/bonding. As I said in an earlier post above, I had a discussion with an electrician some years ago about the fact that my three service equipment type transfer switches were NOT connected with an GEC to the ground rod. I asked him if he considered the electric meter box to be service equipment and he said no but the GEC needed to be connected to the service equipment, notwithstanding the GEC was already connected at the meter enclosure. Later I emailed him a link to Mike Holt's video on this subject and he admitted he was wrong.

I suppose all I need to do is remove that ground wire from the ground rod to the solar service equipment ("safety switch"), being sure to leave the bond screw installed.

BTW, I noticed today that I hit 12.9 kW peak production.

Yes, my panels are in 7 groups of from 4 to 6 panels each facing several orientations. There is no shading from trees. The roof is complex, with many different sections, all at 23˚ pitch, so not too steep. It is not possible to get more than 6 panels on any one section due to the setbacks the building department requires. I might be able to get 20 more panels if I max out the remaining sections.