Recommendations: GFCI Inverter for off-grid type setup with small subpanel

[Mark_B]

Hey all. I'm looking for recommendations for an inverter running off a 100ah 24v Lifepo4 battery bank to power some odds and ends in my garage.
But I want to run it through a sub-panel with a breaker or two and have GFCI protection either at the panel and/or the outlets.
The basic cheap inverters don't seem to support this.
I need about 3000 watts give or take.
Any recommendations?
Thanks!

 

[SunnySoCal]

Yellow Jacket 2 ft. 12/3 SJTW In-Line GFCI Heavy-Duty Cord with Multi-Outlet (3) Power Light Block 2816 - The Home Depot

The 2 ft. with In-Line GFCI and 3-Outlet Lighted Power Block is ideal for workshops and garages. The ground fault circuit interrupter detects ground faults and cuts off electricity to reduce the risk of electrical shock. This product has a 2 ft. cord, a Powerlite indicator and GFCI test and...

www.homedepot.com

Edit: Just realized this is only 1/2 the wattage you need. Your need for 110 VAC or 220 VAC? IF 110 VAC that's almost 30 Amps so make sure you get the right wire size to run this.


Could you get away with just this? I have an inline gfi but it's probably only rated to 5 amps, I'd have to look. I thought the norm was for wet environments. I guess if you're running tools it's a good idea to have one...

 

[BentleyJ]

Could you clarify what you mean by "The basic cheap inverters don't seem to support this." Almost any kind of basic Inverter could have the output terminals connected to a subpanel with breakers. Are you referring to a possible grounding issue that prevents a GFCI from operating properly? If so then an MPP Solar LV series should work. It is designed to take in both utility power and solar as a source for charging the batteries. Since it is designed for a utility neutral that is normally bonded to ground at the main panel and your subpanel will be connected to ground as well, A GFCI breaker in the subpanel or a GFCI receptacle or GFCI extension cord/splitter/spider box should work. Keep in mind that in a subpanel neutral and ground are NOT connected. This is to prevent the ground wire from becoming a secondary path for current returning to the Inverter on the neutral leg.

 

[Mark_B]

Could you clarify what you mean by "The basic cheap inverters don't seem to support this." Almost any kind of basic Inverter could have the output terminals connected to a subpanel with breakers. Are you referring to a possible grounding issue that prevents a GFCI from operating properly? If so then an MPP Solar LV series should work. It is designed to take in both utility power and solar as a source for charging the batteries. Since it is designed for a utility neutral that is normally bonded to ground at the main panel and your subpanel will be connected to ground as well, A GFCI breaker in the subpanel or a GFCI receptacle or GFCI extension cord/splitter/spider box should work. Keep in mind that in a subpanel neutral and ground are NOT connected. This is to prevent the ground wire from becoming a secondary path for current returning to the Inverter on the neutral leg.

Below is the inverter I have, and Giandel has confirmed to GFCI with this one.
Yes, the grounding issue preventing GFCI from working as expected.
I have no expectation of connecting to grid, even to charge. So not sure how this might affect the circuitry. ?
Thanks for the response!

 

[BentleyJ]

I'm not an electronics expert by any means. My understanding is that it depends on the inverter circuitry having floating (isolated) outputs. An easy test you could do yourself on an inverter would be to check continuity between GND and the neutral (wider slot on the receptacle) If they are connected then a GFCI should work as long as all the grounds get tied together.

 

[izmail]

Maybe this may help. I had same problem once, even had an exchange with Giandell about the issue and their response was that their inverter ( as any "cheap" inverter) has floating output and grounding one leg is not recommended, but possible. In which case they recommend to use GFCI.
This video

kinda explains how to do that, RCD is European term for GFCI.
To make it absolutely correct an isolation transformer is needed, regular ACME 480/240/120 will work. That what I ended up with. Only problem - cost about $250. One side of secondary winding is connected to ground wire and ground wire connects to the ground at the same point as grid ground

 

[12VoltInstalls]

the grounding issue preventing GFCI from working as expected.
I have no expectation of connecting to grid, even to charge. So not sure how this might affect the circuitry. ?

I recently had this exchange with Giandel regarding GFCI. In your case a GFCI breaker in a subpanel is probably appropriate since I don’t think any standard GFCI outlets are above 20A

If you read that meandering thread I linked the solution is fairly clear. In your case the subpanel would make the bond which shouldn’t ’surprise’ the GFCI breaker.

 

[Mark_B]

I recently had this exchange with Giandel regarding GFCI. In your case a GFCI breaker in a subpanel is probably appropriate since I don’t think any standard outlets are above 20A

If you read that meandering thread I linked the solution is fairly clear. In your case the subpanel would make the bond which shouldn’t ’surprise’ the GFCI breaker.

I will have to give this some time to read and understand. Thank you for posting.