I'm setting up an NHX-10 hybrid inverter with battery backup to ensure whole-home backup and grid-tied operation. My main panel is rated at 200A, but I plan to derate the main breaker to 150A to comply with the 120% rule. I'll use a 70A backfeed breaker for the inverter, and the inverter's AC output is 50A. It has a built-in ATS and is UL 1741 SB compliant. My aim is to power the entire main panel during outages and send solar/battery power to the home/grid when operational.
Here's the wiring plan:
* Install a 70A breaker from my main panel to the Grid In on the NHX-10.
* Connect the Load Out from the NHX-10 to another 70A breaker on the panel.
* Batteries and PV will be directly wired to the inverter.
* I want to avoid supply-side tap connection if possible.
I have a couple of questions:
1. Is it safe and code-compliant to connect the inverter's Grid In and Load Out to the same panel as I'm planning?
2. Are there any concerns regarding inverter damage or code violations with this looping setup?
3 Answers
You definitely need to ensure that the grid and your load output aren't active simultaneously on the main panel. Installing a generator interlock kit would help prevent that. Just make sure the grid main breaker and your 70A grid breaker are turned off when the output breaker is on.
If you need professional help designing your solar system, there are services that can provide permit-ready drawings with PE stamping. A bit of research can go a long way!
If you’re feeling overwhelmed, you could consider just going for a 200A inverter instead! It might cost more upfront, but you'd likely save time and hassle with the setup. Just a thought!