Outback GVFX 3524 grid tie interacting with two utility meters

[gogreen]

I am installing a GVFX 3524 with Midnite Panel 250 AL. Its 1kw system of solar with battery back-up for critical loads on the frige and furnace. This system is a grid tied interacting with two utility meters, the usual meter that measures household consumption and the other, a revenue meter, measuring the output of the solar energy. The utility is concerned that the system, as wired, according to the epanel diagram provided, has the backed-up loads feeding through the inveter into the solar output negating the solar generated. I think they're right. The internal wiring to and from for the inverter was wired according to the Midnite epanel instructions provided. I'm not sure how the sub electrical panel fits but I believe it gets its power from the AC hot out on the epanel. I'm not an electrician and this is my first install so some of this is not entirely clear to me. Any help would be appreciated. Thanks!

[Rock]

AC input (to inverter) from main breaker! Should be around 30 amp breaker in main panel.

AC output of inverter goes to subpanel for critical loads.  

DC input to inverter comes from battery bank.

When power production exceeds the needs of the subpanel and efficancies of system, power from solar panels will flow from inverter to main panel (30 amp breaker) then from main panel to meter/meters.  These legs are dual direction! feeding subpanel when solar panels are not producing and sending solar power back to meter/meters when excess is produced.  

When the grid is down a electronic transfer switch within the inverter shuts down interaction with grid and systems charges batteries and/or supports subpanel loads.

Take a peak at outbacks instructions it will help.  

[boB]

I'm sorta confused by both of these...    On the first post,

"the backed-up loads feeding through the inverter into the solar output negating the solar generated."

??Into the solar output???

~~~and~~~

"switch within the inverter shuts down interaction with grid and systems charges batteries and/or supports subpanel loads."

???shuts down interaction with grid and systems charges batteries???

I think this second one is trying to say that when the grid comes back UP the system charges the batteries.

boB

[jmk]

 Your grid power should only be going to ac one in on the inverter. Then the inverter determines when to send it back to the grid by an increase of dc voltage. If you have a sub panel ran by the inverter it should be hook to ac out only. That panel shouldn't be hot from the main panel except by the inverter. If you have grid power going to booth the inverter and to the sub panel then you don't have it hooked up right. I am speaking from experience from using an Xantrex inverter but I can't imagine that they would be different in that aspect. It's a big manual but read it again. The inverter should sell the power back to the same place it gets its power from which with Xantrex is ac in one. With Xantrex its a 60 amp breaker. I'm not familiar with outback but it seems to me like your sub panel is in between the grid and the inverter. If you do have it hook up that way then you are getting grid power to booth ac in and ac out terminals on the inverter. It's just what it sounds like to me? I could be wrong.

[Tom in NH]

Hope I'm not hopping on to this discussion too late, but I wired an outback GVFX3648 and an epanel recently. If your subpanel is powered from the inverter's AC Hot Out, it should be isolated from your other ac outlets and will continue to operate even after the grid goes down. You can test this by opening the AC IN breaker on the epanel. The sub panel should remain energized.

You should not use the sub panel to feed anything that goes back to your utility service panel. The GFX AC OUT must be isolated from the utility power.

My system uses a single meter and I'm having a hard time imagining where you are placing your second meter to measure power output unless it is on the AC IN line. The GFX AC IN wire connects the inverter to your utility service entrance panel. When the inverter is not able to supply the loads on the AC OUT line, it will draw utility power to supply the loads, and your meter will run in one direction signifying consumption of utility power. When the solar panels are providing adequate power, the inverter will feed excess ac power back to the utility service entrance panel (through AC IN) where it will feed other household loads or go back out onto the grid. In this case your meter would run in the opposite direction signifying production of solar power.

The inverter has an internal transfer switch that prevents AC HOT OUT from feeding back to the AC HOT IN line. As long as you keep all the circuits coming from AC HOT OUT isolated from the rest of you house wiring, you should be ok. I think a load break test would confirm that you're not backfeeding any power to your main panel. On a day when you are SELLING consistently, put a volt meter on the breaker terminal screw your AC HOT IN wire is connected to. Open your main breaker shutting off power to the building. You should see the volt meter drop from 120 vac to 0 vac. If it doesn't your GFX inverter is energizing your service entrance panel because something is wired incorrectly.

Tom

T