Off-grid Inverter - FailSafe question

[wbarkwell]

First - sorry for my elementary question and terminology ....

I am preparing to receive an EG4 12000XP. My plan is to send power to the XP by way of an breaker in my Main Electrical Panel (via the inverter GRID connection). The inverter would pass the power from the XP to the Main Breaker of the CRITICAL LOAD PANEL (via the inverter LOAD connection). All critical circuits will receive their electricity from the XP via this panel.

My question - If the XP fails but the grid is still up, I want to be able to provide power to the CRITIAL LOAD PANEL by working around the failed XP. It would seem some type of Manual Transfer Switch with the circuit from the Main Electrical Panel as the source and the XP and a DIRECT to CRITICAL LOAN PANEL (via a branch breaker) being the two "LOADS" from the Transfer Switch. I would then have to install a Generator Interlock kit on the CRITICAL LOAD PANEL to choose between the XP connection and the DIRECT LOAD connection.

After your head stops spinning maybe you can provide some feedback ?

Thanks

 

[Mattb4]

Something like this but sized for your AIO?

 

[mciholas]

Simplest, cheapest way is to have a "main" breaker in your critical load panel and interlock it with a breaker that comes from the solar system load output. Like this:



The "main" breaker is fed by another breaker in the main panel. When the "main" breaker is on, the critical load panel is fed by the utility. The 2 pole breaker on the top right column is fed by the load output of the inverter. When it is on, the critical load panel goes through the solar system. The slider between them assures that only one is on at any one time. It would be very bad to have them both on at the same time.

In most subpanels, you can add a main breaker to it if it doesn't have one. That was the case with mine, I removed the lugs and installed a 60 amp main breaker instead and the cover had the knockout for the breaker.

Transfer switches (at least the ones you can use in the US) are expensive, big, ugly, etc. The Europeans have some nice ones, even ones that automatically switch, but not UL listed here, so a no go.

Mike C.

 

[wbarkwell]

Simplest, cheapest way is to have a "main" breaker in your critical load panel and interlock it with a breaker that comes from the solar system load output. Like this:

View attachment 256702

The "main" breaker is fed by another breaker in the main panel. When the "main" breaker is on, the critical load panel is fed by the utility. The 2 pole breaker on the top right column is fed by the load output of the inverter. When it is on, the critical load panel goes through the solar system. The slider between them assures that only one is on at any one time. It would be very bad to have them both on at the same time.

In most subpanels, you can add a main breaker to it if it doesn't have one. That was the case with mine, I removed the lugs and installed a 60 amp main breaker instead and the cover had the knockout for the breaker.

Transfer switches (at least the ones you can use in the US) are expensive, big, ugly, etc. The Europeans have some nice ones, even ones that automatically switch, but not UL listed here, so a no go.

Mike C.

Thank you all ... To make this clearer for me (dumb it down for me)... I have attached my VERY SIMPLE chart. Note that I do NOT have any solar .. basically I am using thie XP as a UPS for my Critical Loads in my house ..

2 routes for the Electrical service controlled by Critical Load Panel

Primary ... Main Panel Feed (via Breaker #1) > Inverter > Critical Load Panel (via its Main Breaker)
Secondary (XP Fails) > Main Panel (via Breaker #2) > Critical Load Panel (via Branch Breaker)
Power to Critical Load Panel is manually selected by choosing between the two Breakers in the Critical Load Panel (with Interlock limiting an either or scenario)

Another question that I have - if I understand correctly the XP feeds the LOAD via a 50 Amp breaker (I am concerned about the adequacy of this and then started thinking about the Smart Load and can these two be combined for 100 Amps) - but ... in the meantime ... if the XP can provide 100 Amps via AC Bypass and the LOAD is serviced via the Critical Load Panel with a 50 Amp breaker - what happens to the other 50 Amps (of the 100 Amp bypass) ?

Thanks for your thoughts and any help you can provide to someone who is obviously over their head.