Inverter pass through for whole home battery backup system. -Please advise.

[225lakesidedrse@gmail.com]

We're just starting to design our first system, and have landed on a "whole home" battery backup with hybrid inverter. Our goals:

• Install per code (safety and reliablilty first)
• Limit load to: Refridgeration (3); Lighting; Computers/Network; nat gas water and heat.
  
• Automatic switch to battery upon outage.
• Bypass for Inverter Maintenance.  Allow switch back to grid input. *
• Support for generator input. Might use "chargeverter"
• No net metering or grid sell back

We're in Michigan, and our lot has a lot of tree coverage, so solar is a secondary.

In addition to all the other research, I've read through this article a few times.
200 amp vs. 100 amp Inverter pass through By Robin Gudgel, MidNite Solar Read Robins Article On 200A Passthroughs: link to the article here  The new MN15-12KW-AIO All In One seems interesting as it might help with some automatic load shedding.

Questions we're working through:

• What kind of wiring are code/safety/reliability compliant that will achieve our goals? 
• Are there any good sources for a wiring diagram for my desired configuration?

[Wizbandit]

I briefly glanced at the ticket you submitted to support. I have a few answers.

The MN-ONE AIO can not be directly connect to the grid like from the meter to the AIO without a suitable disconnect and over-current protection device.  Disconnect OCP disconnect devices MUST be Listed and approved to be used as such.  They will have usually a UL STICKER that says "Suitable for use as service disconnect equipment" or something similar.  The MN-ONE does not have this service listing.

There is no "Built-in" Inverter BYPASS.  If the inverter quits you have to do a bunch of re-wiring to get AC IN to AC OUT working after you remove it.  You will need a 100 amp external by-pass/transfer switch system if you want to be able to bypass the MN-ONE AIO.

[225lakesidedrse@gmail.com]

I've landed on a design from the EG418kPV Manual p34 "Whole Home Backup with Feeder Tap" configuration.

https://eg4electronics.com/wp-content/uploads/2024/04/EG4-18KPV-12LV-Manual-1.pdf

There are benefits to this kind of config, along with extra costs.  We're running this by our electrician and local inspector.

This design includes a bypass switch for inverter maintenance.

[225lakesidedrse@gmail.com]

This "Feeder Tap" approach seems to have the benefit of not being dependent on your main panel's bus rating  as  the "Backfed Breaker" approach is, which can be more risky (in the EG4 18K Manuel pp31 see the note on "Permitted Combinations of Main Breaker Ratings and Main Bus Ratings .)

Here's the related code 705.12 Load-Side Source Connections https://up.codes/s/load-side-source-connections