"I think the NEC stipulates that the grounding conductor is to be run with the grounded conductor and presumably with the un-grounded conductor". What?. I am going to act like I didn't read that. Thanks a million, FilterGuy and smooth. I am going to wire it exactly as your 1st diagram that you replied with and disable bonding on only one inverter and never look back.
Signature Solar EG4 6.5K Off-Grid Inverter | 6500EX-48
- Thread starter RoySalisbury
- Start date
Zwy
Emperor Of Solar
If both screws are removed, you will need N-G bond in the subpanel after the inverters. The reason why is input Neutral is switched by the internal transfer switch, thus there would not be any N-G bond for ground fault protection.
With a N-G bond in the subpanel, when you enter bypass mode with AC input, you will have N-G bond in the main service panel and the subpanel.
This is why you can't remove both screws unless you will only use the inverters in off grid mode without AC input wired in.
Zwy
Emperor Of Solar
Ian at Watts247 showed the LV6548 running only on PV and powering multiple shop tools like chopsaw, tablesaw. There is a Youtube video if you want to see it.
Zwy
Emperor Of Solar
You need the 3 pole double throw to switch Neutral from the main distribution panel.
Zwy
Emperor Of Solar
No, there is an internal relay that switches off N-G bond.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
That is a good idea no matter what. There is no avoiding a loop in the neutral when you have multiple inverters, so having it all sealed up in a faraday cage would go a long way toward reducing any potential RFI issues from ground or other loops. However, in options with multiple inverters, the conduit itself can become a broadcasting loop if you are not careful. (With multiple inverters, I think I would go with metal cable trays that hold all the wires).
Normally I don't worry so much about loops, but when an inverter is involved, you are dealing with the quintessential RFI noise generator. Consequently, I watch for loops and try to avoid them if at all possible. Loops should be avoided, but sometimes they are almost impossible to avoid...particularly if it is in a metal building.
Zwy
Emperor Of Solar
That was discussed at length and how I came up with my diagram. The only parallel path is between the 2 inverters under inverter power. This was the best design without modifying the unit by removing any screws. My biggest concern with any screw removal is electrons returning to source and in a ground fault situation there could be the possibility of not 100% protection. With both inverters N-G bonded under inverter power, while there is objectionable current for the few feet between inverters on G, it would provide 100% ground fault protection.
Some will argue the bonded N-G in the one inverter will suffice, but as this is a relay, what is the likelihood of both relays failing at the same time?
Zwy
Emperor Of Solar
One can always use the units as off grid power only and add an external battery charger for power off the grid with some efficiency loss and the possibly not able to run full loads as desired.
It's not that hard actually, purchase a 3 pole double throw rated for at least 60A and follow the diagrams given.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Zwy
Emperor Of Solar
One member here tried a Reliance 310C transfer switch wired where the neutrals remained in the main panel.
It would trip the inverter immediately as it created a ground fault scenario. Remember, electrons return to source.
Zwy
Emperor Of Solar
I'm trying to remember, we had that discussion. It would work with one screw removed in an inverter (which you know I do not advocate and you didn't advocate before).
42OhmsPA
What's in a title?
Exactly what I had pictured in my head and planned to draw tomorrow. What are you using for your diagrams? I was going to try visio and end up making something really crude in excel ?.
Now I need to make the big decision if I want to be the test dummy seeing how these handle a well pump and other surges like table saws, band saws, etc; I can always add 2 more.
@FilterGuy @Zwy and all others thank you for your help and contributions, it's truly appreciated. Huge thanks to Will for making it all possible here as well.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Did you see the resource I posted with all the different scenarios?
Grounding and Bonding for MPP LV6548 and EG4 6500EX-48
Click on the orange download button above to get the document. This document shows how to handle grounding and bonding with the MPP LV6548 and EG4 6500EX-48 Warning 1) EG4 requires explicit permission from the distributer before removing the...
diysolarforum.com
Plain ol' Powerpoint
42OhmsPA
What's in a title?
Just downloaded it, made mental note to check it earlier and forgot.Did you see the resource I posted with all the different scenarios?
Grounding and Bonding for MPP LV6548 and EG4 6500EX-48
Click on the orange download button above to get the document. This document shows how to handle grounding and bonding with the MPP LV6548 and EG4 6500EX-48 Warning 1) EG4 requires explicit permission from the distributer before removing the...
Plain ol' Powerpoint
It shows I don't use PowerPoint as much as a should, I dread it because using it normally means I'm doing boring presentations for work.
ryantboldt
New Member
- Joined
- Jan 13, 2022
- Messages
- 7
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Isn't that redundant??
A Sol Ark 15k video would be sweet
Subdood
Photon Wrangler
Thanks again..This is to avoid ground loops that might cause RFI issues.
You could do this as well.
View attachment 96473
This works fine and as far as I know, is to code However there are a lot more connections in the ground path to the critical loads box. I like to try to minimize the connections between any one point and the main grounding spot...... (Yes, my anal-retentive nature is showing
Since the two indoor panels would be right next to each other, it wouldn't be difficult to run a ground wire to the sub panel from the crit panel to match your original schematic. I'm moving hots and neutrals anyways, so one more wire shouldn't be a problem. What gauge wire would be sufficient for this? Guess I'll just have to run two 6 gauge wires from inverter output to the crit box.
You said the second version would cause a ground loop which might cause radio interference issues, is that the worst problem? What are you talking about here? Is there a safety issue also?
Last edited:
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
I think the second one creates a lot more connections between the critical load panel and the central grounding point in the main box.
This is not a ground loop and is perfectly legit. I just like to minimize the connections between points on the EGC system. (Star configuration vs daisy chain config)
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