Residential Fridge/Inverter Install

[Bobtop46]

Thank You all for the reply.

Solarman:  as stated in my update all the negative wires go to one end of the shunt, only one wire goes from the shunt to the battery.  I just have not updated the diagram.  The inverter negative wire goes to the shunt not the chassis.  I am talking about the green inverter ground wire (6 ga) goes to the same stud as all the rest of the 12v grounds, should I move it to its own stud?

John from Detroit:  I am not attempting to power my entire main panel or a sub panel only 2 circuits.  My inveter has not built is transfer switch.  it is a Xantrex Prowatt 2000w Inverter, with 2 15amp relays built specifically for it, and remote.  Hence, I don;t need a dedicated branch breaker or sub-panel.  The relays have 3 (12/2) wires.  The first is a plug that goes to inverter, the second is wired to the circuit breaker in the main panel, the third is the load side where I moved the wire from the circuit breaker too.  When AC is available (gen, or shore) the relays by pass the inverter and supply AC.  When no AC is available it switched to the inverter power.  I am already at 00 or 2/0 wire gauge for entire set up.

Gary: You hit the nail on the head.  My pre-inverter AC setup had no GFCI in the circuit.  I used the exsisting AC outlet from the old Dometic RV fridge to plug in the new Samsung.  That is why everything works from shore power or generator.  The problem is the GFCI on the inverter.  This thought caused my to do research where I found this from support-us.samsung.com

https://support-us.samsung.com/cyber/popup/iframe/pop_troubleshooting_fr.jsp?modelname=RFG297AARS/XAA&idx=420969

If the refrigerator is not powering on at all, verify the following:

"Verify the circuit breaker has not been tripped.
Unplug the refrigerator.
Verify the power cord is not damaged.
If the outlet is a GFCI outlet, press test, and then press and hold reset to confirm the GFCI was not tripped.

Important: If the refrigerator continues to trip the GFCI outlet, use a non-GFCI outlet.

Verify the outlet is functional by testing with another device, such as a lamp.
Verify the outlet is a 120 V, 60 Hz properly grounded outlet.
Plug the refrigerator back in.
If the issue continues, service is required."

From here I will have to look into getting an inverter that doesn't have a GFCI outlet as the AC source.  I am also thinking about adding an inline 15 amp circuit breaker after the relays to protect the system from AC overload.  I am not sure that it is needed because the inverter has overload protection on the AC side also DC high volts and low, and over temp protection.  The two circuits are the bedroom and dining room  (this circuit has 2 outlets, the fridge and one by dinette table)  I don't even care about the bedroom circuit and for this test trip I didn't even have it plugged into the inverter.  This whole thing is only to power the fridge while going down the road. 

 

[Gary RV_Wizard]

The electric heat element in an RV fridge is a common source of ground faults, but you state that the fridge runs ok via inverter as long as you dodn't start the engine. That tells me that the fridge heater wiring is NOT the cause of the GFCI trip.  You can ignore all that advice on non-GFCI, cause your fridge does power up ok.
The GFCI trip is telling you there is a wiring problem.  Switching to a non-GFCI cicuit merely suppresses the warning; it does NOT fix the problem. Do not ignore it.


Your inverter is designed to have a chassis ground wired to a lug that goes directly to the RV chassis (not battery negative or shunt). The install instructions for your ProWatt cover this explicitly - follow them!

 

[Bobtop46]

From what I can find on the Samsungs is that they create EMI that is known to trip GFCI outlets, the wiring is fine.  My first test (before going on the road) was parked and I did not run the test long enough.  I can not duplicate that test anymore.  The GFCI trips every time right away.  At home I ran an extension cord (10 ga. 25ft) to non-gfci outlet in the house and the fridge runs fine, uses 200 watts on start up until it reaches temp them drops to 100 watts.  I them plugged it into a GFCI outlet and it tripped right away.  This is a known Samsung EMI issue.

I did follow the directions exactly as far as the green ground to chassis goes.  That is where it has been since install.  It does share the same stud as the rest of the 12v systems grounds (i.e the converter) I did put the inverter ground on the bottom of the stud closest to the chassis on bare metal.  This stud is shared by 2 or 3 other ground wires. Leading to to think the inverter needs its own stud.

A deeper discussion on why the GFCI doesn't work on the 2 circuits powered by the inverter.  Short answer is no ground on the AC side on those two circuits.  I moved all 3 wires (black, white, bare) for the fridge from the circuit breaker to the load side of the relay.  Before this the ground wire for the circuit went to the ground bar in the main panel which is grounded through the plug at the pedestal or by the generator to the chassis.  In a perfect world the new circuit would be grounded by the relay plug that goes to the inverter thru the inverter ground, that is not happening either because the ground for the inverter was not meant to ground the loads and doesn't, or  the inverter expects the loads to be grounded before they reach the inverter, or the ground wire needs its own stud.

Last but not least the Samsung just will not run on a circuit with a GFCI (as stated on the support web site) and I need a direct wire inverter.

 

[Gary RV_Wizard]

2. When there is no AC available the fridge runs off the inverter (tested), about 100 watts on cycle.

Then I don't understand how you made this statement in your earlier post. How did it work on the inverter if it always trips the GFCI immediately?

I also think you are wrong about the reasons for the tripping. Lack of an AC ground wire does not in any way interfere with GFCI operation or cause tripping.  GFCIs are utilized on old houses that are strictly two-wire systems, no grounds anywhere.  Much of what you find in the internet re GFCI is myths from the 80's.  But you seem convinced, so I guess we will just have to disagree about that.
Best of luck with your problem.

 

[solarman]

Thank You all for the reply.

Solarman:  as stated in my update all the negative wires go to one end of the shunt, only one wire goes from the shunt to the battery.  I just have not updated the diagram.  The inverter negative wire goes to the shunt not the chassis.  I am talking about the green inverter ground wire (6 ga) goes to the same stud as all the rest of the 12v grounds, should I move it to its own stud?

ah.. ok, I had not seen the updated schematic... glad you corrected that.

the green ground wire bonds the inverter chassis to the vehicle chassis

 

[Bobtop46]

Thanks again for all the replies.

Gary I know that you are right and agree with you.  I have resolved the issue.