Another inverter/solar grounding question for the experts
Hello all,
I have just recently installed and wired in my new solar system to my TT which includes the following:
- (4) Deep Cycle / Marine 12V batteries at 120Ah each
- Xantrex Prowatt SW2000 inverter
- GoPower 30A Automatic Transfer Switch
- Sub-panel for breakers to be powered from inverter
- 250W solar panel (plan on adding another 250W panel)
- Tristar MPPT-45 Charge Controller
- Trimetric 2025-RV battery monitor.
I have given it all a fairly thorough testing and it seems to be working pretty well except for one problem. When I run the microwave off the inverter, it "sometimes" trips the GFCI on the Xantrex inverter. When I say sometimes, it seems to be about 50% of the time. I can reset the GFCI and I am away to the races again, but this could be a real pain after awhile.
This got me to thinking about the grounding. I have a decent electrical understanding but not a whole lot of practical experience and am not familiar with the standard wiring practices in an RV. Thinking about grounding gives me a headache. I have done some searching and reading but am still not clear on what is required.
The trailer is basically brand new. Straight from the factory/dealer, the battery had "several" wires connected to the battery - most were from the positive terminal and only one #8 from the battery negative. There is no obvious place I can find where this negative wire is frame grounded I can only "assume" that it runs back to the converter ground terminal strip and that terminal strip is connected to the trailer frame. All these wires "disapper" into the underside of the trailer and it would be very difficult for me to trace exactly where they are going. Rather than changing them, I just left them all connected as they were when wiring in my new components.
When I connected my components, I ran the positive/negative from the battery to the inverter. The inverter has a separate grounding terminal. Then inverter instructions say to connect a cable from the inverter ground terminal to the trailer frame. I did not follow this exactly. From the inverter ground terminal, I joined this ground cable with the ground cable from my Tristar charge controller and from my solar panel, and then ran a bigger ground cable back to my converter which I connected to the grounding strip in the converter panel.
On the A/C side, my inverter comes with two GFCI outlets. I built a cable with a 3-prong plug that I have plugged into the inverter outlet and then ran that cable to my ATS. The other cable to the ATS comes from a 30-amp breaker in the main breaker panel. At the main breaker panel, the cable going to the ATS has positive terminated on the breaker outlet, neutral on the neutral bar, and ground on the ground bar.
The 3 cables at the ATS (2 in and 1 out) are connected to the positive and neutral connections provided in the ATS with the ground cables all connected to the ground terminal strip inside the ATS.
The outlet from the ATS is wired to a small sub-panel with 3 breakers which power my RV outlets and my microwave. The sub-panel has a separate ground and neutral strip which I terminated all of the cables to. This includes the main supply cable from the ATS and the 3 cables supplying the loads in my RV.
So the way I see it, I basically have all of my grounds connected together including my AC and DC grounds. I am assuming they are also connected to the trailer frame somewhere although I am not sure where. I am also wondering if maybe the neutral and ground are bonded together at the inverter although I am not sure how that is wired internally and maybe this is the problem. If the neutral and ground are bonded together at the inverter, could some of the current be returning via the ground instead of the neutral and causing the GFI to sense a fault?
I think I have everything wired okay but, like I said, I am not familiar with RV wiring standards and am wondering if something I have done is causing my GFI problems. Should I be running my inverter ground directly to the trailer frame as per the instructions? Should my AC and DC grounds be kept separate from one another? Is there something else I should be doing?
Thanks for the help everyone.
I have just recently installed and wired in my new solar system to my TT which includes the following:
- (4) Deep Cycle / Marine 12V batteries at 120Ah each
- Xantrex Prowatt SW2000 inverter
- GoPower 30A Automatic Transfer Switch
- Sub-panel for breakers to be powered from inverter
- 250W solar panel (plan on adding another 250W panel)
- Tristar MPPT-45 Charge Controller
- Trimetric 2025-RV battery monitor.
I have given it all a fairly thorough testing and it seems to be working pretty well except for one problem. When I run the microwave off the inverter, it "sometimes" trips the GFCI on the Xantrex inverter. When I say sometimes, it seems to be about 50% of the time. I can reset the GFCI and I am away to the races again, but this could be a real pain after awhile.
This got me to thinking about the grounding. I have a decent electrical understanding but not a whole lot of practical experience and am not familiar with the standard wiring practices in an RV. Thinking about grounding gives me a headache. I have done some searching and reading but am still not clear on what is required.
The trailer is basically brand new. Straight from the factory/dealer, the battery had "several" wires connected to the battery - most were from the positive terminal and only one #8 from the battery negative. There is no obvious place I can find where this negative wire is frame grounded I can only "assume" that it runs back to the converter ground terminal strip and that terminal strip is connected to the trailer frame. All these wires "disapper" into the underside of the trailer and it would be very difficult for me to trace exactly where they are going. Rather than changing them, I just left them all connected as they were when wiring in my new components.
When I connected my components, I ran the positive/negative from the battery to the inverter. The inverter has a separate grounding terminal. Then inverter instructions say to connect a cable from the inverter ground terminal to the trailer frame. I did not follow this exactly. From the inverter ground terminal, I joined this ground cable with the ground cable from my Tristar charge controller and from my solar panel, and then ran a bigger ground cable back to my converter which I connected to the grounding strip in the converter panel.
On the A/C side, my inverter comes with two GFCI outlets. I built a cable with a 3-prong plug that I have plugged into the inverter outlet and then ran that cable to my ATS. The other cable to the ATS comes from a 30-amp breaker in the main breaker panel. At the main breaker panel, the cable going to the ATS has positive terminated on the breaker outlet, neutral on the neutral bar, and ground on the ground bar.
The 3 cables at the ATS (2 in and 1 out) are connected to the positive and neutral connections provided in the ATS with the ground cables all connected to the ground terminal strip inside the ATS.
The outlet from the ATS is wired to a small sub-panel with 3 breakers which power my RV outlets and my microwave. The sub-panel has a separate ground and neutral strip which I terminated all of the cables to. This includes the main supply cable from the ATS and the 3 cables supplying the loads in my RV.
So the way I see it, I basically have all of my grounds connected together including my AC and DC grounds. I am assuming they are also connected to the trailer frame somewhere although I am not sure where. I am also wondering if maybe the neutral and ground are bonded together at the inverter although I am not sure how that is wired internally and maybe this is the problem. If the neutral and ground are bonded together at the inverter, could some of the current be returning via the ground instead of the neutral and causing the GFI to sense a fault?
I think I have everything wired okay but, like I said, I am not familiar with RV wiring standards and am wondering if something I have done is causing my GFI problems. Should I be running my inverter ground directly to the trailer frame as per the instructions? Should my AC and DC grounds be kept separate from one another? Is there something else I should be doing?
Thanks for the help everyone.
