Wiring from common neutral inverter to a 240/120 sub panel

DAbineri
DAbineri Registered Users Posts: 1 ✭
in General Solar Power Topics #1
When using the inverter I am replacing, I just ran 240 (black and white) and ground from my main panel to the inverter and it supplied the same back to my sub panel to power both 240 and 120 circuits and it worked perfectly.

My new inverter requires black and red at 240v and a white (neutral) and a ground for input (common neutral config?).

My question is how to take the output of the inverter back to the sub panel to have the functionality as the previous sub panel?

The output of the inverter seems to be the same as the input, red,black,white and ground. Do I power the subpanel with the red-black 240v wires? In the sub panel, I have the neutral and ground connected for the old inverter in the sub panel, but I don't believe this will work for the new inverter?   

How should the sub panel be wired in this situation? The new inverter is an EG4 6000xp.

Thank you.
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #2
    For 240vac split phase, normal color convention is black and red for 240vac L1, L2 hot legs and white for neutral.  Ground is green wire.

    There is only one neutral ground bonding that is done in main panel.  No neutral-ground bonding downstream of main panel.

    Subpanel neutral is brought back to main panel neutral bus through inverter.  Make sure the tab on subpanel neutral bus bar to its metal case is taken out so neutral is not ground bonded in sub panel.   The sub panel neutral is ground bonded in main panel.  Main panel case is grounded to outside earth grounding stake.

    All metal cases grounds are connected to main panel metal box which is grounded in main panel.  Metal conduit between boxes does not count as common grounding, it needs to be separate (green) grounding wire.  All metal boxes including any additional breaker boxes for generator or special outlets goes to the main panel ground.

    Ground path is a safety connection and should not be current carrying unless there is a fault.  Ground bonding neutral in more than one point causes neutral current to be shared between neutral wire and ground wire between the two neutral-ground bonding points which is a no-no.

    Now for the caveat, some inverters ground bond neutral to inverter case ground when there is no AC input detected on inverter.  This is off-grid operation.  This is okay since when there is no AC input to inverter there will be no current flowing from main panel and no current on neutral line to main panel.
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