I have an off grid 24vdc system that was installed in March 2009. The system includes:
• Midnite Epanel MNE250AL+
• Outback VFX3524, FM60, mate 2
• 3 Rolls Surrette 8CS25P
• 6 sharp 216 panels
I am now adding a Kohler 8.5 KW generator to the system. Questions:
• I’ve read there should be only one neutral-ground bond. Is this correct? I have a neutral ground bond in the epanel. The Kohler generator comes pre-wired with a neutral ground bond but this can be disconnected.
• What else should I be thinking about? It has been 10+ years since my system was installed.
Thank you!
-cindy
If you asking about what is code you probably want to consult with a local electrician. They probably know what local inspectors want to see in your area.
As far as neutral and ground being bonded - in a conventional house it is usually at the first place where the electric comes down from the service. But I am no electrician.
The idea I believe is so that if anywhere else on the system a hot touches either the neutral or the ground it will trip the breaker. You don't want current ever to potentially running through the ground. Someone else can correct me if I have that theory wrong.
But as far as adding generator to the mix I have no idea the right way it is supposed to be done.
Maybe someone else does.
Larry
Portable generators with outlets shouldn't have the neutral/ground bond removed. Many of those have GFCI breakers or outlets and create problems when attempts are made to connect them to a house. A fixed-in-place generator that is permanently wired to the house power system should have the neutral/ground connection removed unless it is being wired to a transfer switch that also switches the neutral.
Thank you. The Kohler 8.5kw gen is a stationary unit. Will run permanent connection from gen to small breaker box in house (no neutral ground bond) then a 110 leg to Midnite Epanel. The Midnite epanel contains a neutral-ground bond.
This is the plan. Feedback appreciated.
Would like to hire an electrician for this but live in a rural unincorporated area 5 miles outside a village with population 132. Not a lot of electricians 🤣. Even fewer willing to work on PV.
Two additional notes in relation to my last post.
1. Since posting, I've read there may be load imbalance issues from using only one leg of a 240v line?
Xantrex and Outback make 240v to 120v step down transformers for $450 to $600. I would be interested in hearing thoughts on this.
2. I found a more recent Outback Off-Grid Epanel wiring diagram than the 6-30-2007 version I used 10+ years ago when installing my system. The newer version does not show a neutral-ground bond in the epanel. https://www.midnitesolar.com/pdfs/classic_simple_flow_diagram.pdf (https://www.midnitesolar.com/pdfs/classic_simple_flow_diagram.pdf)
Is Midnite now recommending NO neutral ground bond in the epanel?
Maybe you can get a design consult with one of the bigger suppliers of equipment like Northern Arizona Windsun or AltE .
Might be worth a few bucks for them to take the time to evaluate your system and make recommendations.
Larry
Thanks Larry. Didn't know that was an option.
The questions as to where the best location for the neutral ground bond connection depends on situation specific factors: inverter type, off-grid, grid connected, mobile? With no one answer applying for all, it makes sense that the E-panel wiring diagram doesn't include it. Haven't looked at the manual, but it seems like the sort of issue that should be addressed there. For off-grid, making the neutral ground bond in the E-panel is probably the best choice, but doing it in a load center instead is an alternative.
Thank you Kent0. Your explanation makes complete sense. I found the most recent version of my Epanel manual on the website and you are correct, the topic of neutral-ground bond is covered in more detail there.