Please check my wiring/diagram. Did I make any big mistakes or forget anything?
- Thread starter Travis55
- Start date
If you haven't already verify the Voc of 6 panels in series, adjusted for the coldest possible temp is below the 250 volt max. Any breakers on the PV inputs should be rated to the Isc of your panels multiplied by 1.56, this is also the required ampacity of the wires, likely 10 AWG is all that will be required. No breakers or fuses are required, you can use simple disconnects if you want. You should have a disconnect before the wires enter the building and one adjacent to the inverter. A ground wire should be run from the solar panels with the PV input wires and be bonded at the inverter or main panel. All solar panels, and metal of the solar panel mounts should be bonded to this ground wire, 6 AWG ground wire is required where exposed, 10AWG is ok when in cable or conduit.
Your batteries have builtin in breakers no separate fuses are needed. For a 2 battery configuration as pictured run 1 AWG wire between the batteries and a 2/0 from the positive on the top battery and the negative on the bottom battery to the inverter. You could also run separate 1 AWG wires from each battery to the inverter. if you add any more batteries you will want all batteries and inverter to run to a bus bar. Batteries and any enclosure should be bonded to the ground in the main panel.
Use 3 or 2 AWG wire for the run to main panel. Line can be split with a Polaris block or similar to feed both sides a 2 pole 40 amp breaker as the main, no other 2 pole breakers are allowed in the main panel, 120 volt loads only.
Your batteries have builtin in breakers no separate fuses are needed. For a 2 battery configuration as pictured run 1 AWG wire between the batteries and a 2/0 from the positive on the top battery and the negative on the bottom battery to the inverter. You could also run separate 1 AWG wires from each battery to the inverter. if you add any more batteries you will want all batteries and inverter to run to a bus bar. Batteries and any enclosure should be bonded to the ground in the main panel.
Use 3 or 2 AWG wire for the run to main panel. Line can be split with a Polaris block or similar to feed both sides a 2 pole 40 amp breaker as the main, no other 2 pole breakers are allowed in the main panel, 120 volt loads only.
Thanks, the ISC is 13.70 for the panels, that comes out to 21.37A. Could I use a 20A breaker?
Could you please elaborate on this part:
In the diagram I have two sets of leads +-, +- going from the solar panels to each MPPT input on the inverter. Do you mean to run an additional ground from each set of 6 panels to the electrical panel grounding bar? (So 6 cables would be running from the panels to inside in that case)
How about the solar ground mount, do I also run a wire from each ground mount frame to the electrical panel ground bar inside? Total from outside that would be: 4 cables for the solar panels, 2 cables for grounding on each set of solar panels, 2 cables for each metal solar ground mount.
Edit: I saw someone else saying that the solar frame ground needs to go to it's own ground rod that exists right next to the panels, so that any issues have the shortest path possible to travel, and that you don't want it grounded to the same ground as in your main panel. Any thoughts?
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No you will want to use a 25 amp breaker, also 10 AWG wire minimum.
You only need a single ground from each array this can ground both the panel frames and the ground mount. For commercially produced ground mount systems the instructions will provide the details on proper grounding. Other wise you'll need bond the panels, and ground mount to a ground wire. Typically this is done with a 6 AWG wire that links all ground lugs required. This ground will join the PV + and - wires and run to the inverter to be tied in to the buildings ground system. Once in conduit or cable a smaller ground wire can be used but at least 10 AWG. If you use the UF-B cable as in your diagram you can use the ground in this cable for the run to the inverter. You will need three wires from each array +, - and ground all can be in the same cable such as UF-B. If both of your arrays are on the same ground mount struture you only need one wire ot bond every thing and this will tie into the ground(s) running to the inverter.
A separate ground rod at the panels is not required or recommend, for safety resons you want the ground mount and panels bonded to the same ground used in the rest of the system.
