Can eg4-18k backfeed my house, from detached garage sub panel?

[bentz2151]

I have a 200 amp main in the house. Busbar is rated for 200.

100 amp subpanel in detached garage 100 ft away.

12.8kw array and eg4 18kwpv on order+ 1 eg4 wall battery

I see alot on youtube that people attach the inverter BETWEEN the meter and main. I cant do this unfortunately cause its such a far difficult run.

I want to do a grid tie system with one eg4 wall battery as well.

My question is this:

Eg4 inverter has a grid terminal and load terminal. Would I just not use the grid terminals at all?

So just connect into subpanel through a 50 amp breaker to the load side of inverter for backfeeding garage and house?

Or should I run the sub panel feeders into the [Grid] terminals, then put [load] into the mainbreaker on the sub panel?

(and I would obviously follow the 120% rule by Derating the 200 amp and 100 amp sub.)

My other question is, when sending power to the grid, how could that be monitored since id be sending power through 2 panels with household load before it even reaches meter.

Thanks in advance Im learning and reading as much as I can

 

[millsan1]

The latter. Current sub panel feeds into grid on 18, load side of 18 to current sub panel.

In case of a power outage, only the sub panel would be up.

You could backfeed this way, the CTs would control that, but you wouldn't know what was truly backfeed, and what was powering load on main panel, and then backfeeding.

Meaning:
18 is showing 6K of backfeed.
Your main panel is using 2K.
Real backfeed to grid would be 4k.

 

[bentz2151]

I would want the house to be up during an outage, is there a way to wire it so I can have house online, and id probably shut the garage down during an outage to preserve battery capacity.

 

[millsan1]

Only way to do that is to get eh 18 between the house panel and teh meter. In theory you could run some long heavy wire from meter to the garage, then have the wire into the grid side of 18, then load side of 18 to your garage panel, and that panel back to your main panel at home.

But you would have to redo your grouding as well.

Best bet is to figure a way to get the 18 between the meter and your main panel.

 

[bentz2151]

Curious, we rarely lose power here, but if I lost power to grid, and then just closed the main disconnect on house, then set the inverter to export to grid, it would be exporting only to my house.

Then id have power in the house during an outage. Or does the eg4 not work that way?

 

[millsan1]

It could work, but you'd have to have an interlock to prevent accidental backfeeding, which would disconnect the garage during non power outages.

 

[EG4_Jared]

I believe this diagram from our 18kPV manual may be helpful.