Open Ground when testing outlets on inverter

[Tomtennant]

I wired the light bulb between neutral and ground. I also added a 5A fuse in the line. When wired this way, the voltage from neutral to ground goes to about 50 mV. The voltage from Line to Neutral is 120V, as expected. The light bulb does not come on and the 5A fuse does not blow.

I do have continuity from the AC output ground to the grounding lug on the case of the inverter. There no internal connection (infinity ohms) from the AC output neutral to the AC output ground and the case grounding lug (when inverter is not powered).

Based on “Grounding Made Simpler” - I think this means I can wire up the Line, Ground, and Neutral wires to the breaker box. My breaker box is Neutral/Ground bonded. I also have a grounding lug on the outside case of the inverter. This one should also be connected to the grounding rod (essentially the ground inside the breaker box). Is that correct? My instruction manual says that “the ground terminal must be connected to the ground wire” and that for a fixed location install “connect the grounding terminal to earth”.

Edit: However, If I connect the AC output ground to the grounding bar in the main breaker box, and run a grounding wire from the inverter grounding lug back to ground (either to the grounding bar in the breaker box or to the grounding rod) this will create a ground loop. So, I should just leave the grounding lug disconnected?

Do I need to ground the battery negative? Where does it get grounded? I’m lost.

 

[Tomtennant]

Thinking this thru…. Since the external grounding lug is connected internally to the AC output grounds, If I connect both, I will have a ground loop. This may or may not be bad but can cause some noise. However, since the AC output ground and the ground lug on the case are internally connected, I just have to connect one, not both.

Still not sure if I have to connect the battery negative to ground. Case ground or create a separate earth ground. This wire should be gray or white since it is DC ground.

 

[aicragleon]

I have a WZRELB with the following description from ebay... "Pure Sine Wave Inverter 3000W Power Inverter 12V to 120V Off Grid LED Display". It does not have the 60-0-60 scheme (link below, description for when link no longer works). I performed the "fix" and my stock EVSE is working now. My socket tester shows the outlet is wired correctly. I only had 2 wires connecting to the chassis grounding screw and they were not blue, but black. I removed the single wire coming from the terminal block and kept the circuit board wire attached. I also first tested it with a homemade neutral ground bonding plug and the EVSE was faulting without it, but works perfectly with it so now it is time to make a "permanent" bond at the terminal block. Thanks for this fix.

Pure Sine Wave Inverter 3000W Power Inverter 12V to 120V Off Grid RV LED Display 600346542785 | eBay

Full power rated power and double the surge power. 3000W rated power, 6000w surge power for a few miliseconds. Continuous Power 3000W. Big and clear MCU LED Display for DC Volt and AC Volt output to moniter the actual working status.

www.ebay.com

 

[Tomtennant]

I still have a question about this. I do have the floating 60-0-60 issue when not connected, but testing with an incandescent bulb and fuse as recommended shows that it will go to “normal” when wired or supplied with a load.

The ground plug on my AC outlets is wired to the case (0 ohms) and the AC output lugs for direct wiring. Since my house has the ground and neutral bonded, I should not have to ground the case of the inverter, right? If I also ground the case (to earth or to the panel ground) that would created a ground loop.

Also, do I need to ground the inverter to the battery in any way? Or does having the pos and neg terminals connected suffice?

 

[Hedges]

Ground pin of AC outlets and case of inverter should be wired to ground wire of house and ground rod. That ensures case and any appliances plugged in do not shock people who touch them.

There should be only one place where neutral and ground bond together. If neutral of your inverter is connected to neutral of the house, that would be at house's service entrance where ground rod is. For an RV plugged into shore power, it is at utility entrance of the facility providing shore power. When an RV is off-grid, then the neutral/ground bond is typically provided at its inverter, by a relay which closes when off grid.

For an inverter with 60-0-60, I do worry that grounding neutral might drive battery terminals to an elevated AC voltage. Such inverters don't seem appropriate for wiring into a house or cabin. A transformer could fix that.

 

[Vincentdurkee]

HaldorEE,

I have 2kw and 5kw inverters by Reliable. I think the 2kw is the same one that you do. The 5k one that I posted having the live ground, I did not perform this fix on because I believe it will not actually fix, but the 2kw inverter I have did not have the live grounding problem. I performed the fix that they mentioned, and it resolved my grounding issue. I was able to plug in the Car Charger, and I tested it with an inline GFI breaker, and it passed. The 2kw inverter I have was able to power my microwave but just barely.

If you're running multiple things of the Inverter I find 5kw a good size. I have have had running a 12000 and 5000 btu Air conditions, the refrigerator, microwave, and various other smaller things running on it at the same time. Not on the same outlet of course without issue.

I've had no issues running my electronics of the 5kw inverter with that live ground problem. I've been powering them for about 8 months.

Can you send me a picture of how you bonded the terminals? I'm far from an electrician and when I go plug my car into the 5k inverter it's giving me the ground issue.

 

[steviep19]

Can you send me a picture of how you bonded the terminals? I'm far from an electrician and when I go plug my car into the 5k inverter it's giving me the ground issue.

Look a few posts back, woodshed1 posted really detailed pictures of his, and that’s exactly what I did

 

[sparkyv]

Hello. I have the same issue with the open ground, same 3k reliable inverter, (2nd inverter). ( I am using a auto transfer switch and tying all grounds together, house and inverter.) I think I ruined the 1st 1 because I bonded the neutral to a house main panel ground which gave me a grounded neutral which I thought was great. Everything worked, But after 1 month the inverter died. So this time I am not bonding the neutral to grnd. But I grounded the inverter chassis to house grnd. I would think that if I connect the neutral from inverter to the inverter chassis which is grounded I should be good. Is that what is happening in the 2 pictures you posted and what the manufacturer recommended?

 

[steviep19]

Hello. I have the same issue with the open ground, same 3k reliable inverter, (2nd inverter). ( I am using a auto transfer switch and tying all grounds together, house and inverter.) I think I ruined the 1st 1 because I bonded the neutral to a house main panel ground which gave me a grounded neutral which I thought was great. Everything worked, But after 1 month the inverter died. So this time I am not bonding the neutral to grnd. But I grounded the inverter chassis to house grnd. I would think that if I connect the neutral from inverter to the inverter chassis which is grounded I should be good. Is that what is happening in the 2 pictures you posted and what the manufacturer recommended?

Sparky,

I don't think you should be connecting the neutral to the inverter's chassis. The whole point of one of those steps is to isolate it from the chassis. Remember fault grounding is seperate from earth grounding. Fault grounding is providing a path back to the source, which would be the inverter, not the grid.

I'm not totally sure with your scenario, but ya you should never hookup the neutrals to the house's panel when off gird. But I did as described by the manufacturer, which bonded the neutral to ground at the inverter. I also run a few transfer switches and have had no issues running this way since the original post.

The way I understand it is , unless there's a fault, the grounds are attached to the chassis of the device at the other end, so even though they're bonded to neutral, they cannot complete a circuit, unless their in a faulted state, which is the whole reason for having them.

I've used these, which do have the grounds connected, but does switch the hot/neutral wires. if that helps.

https://www.amazon.com/Xantrex-8080915-PROwatt-Transfer-Switch/dp/B004S5Y158/ref=sr_1_5?crid=2LWLR06DB5OBM&keywords=automatic+transfer+switch&qid=1654790466&sprefix=automatic+transfer+switch%2Caps%2C96&sr=8-5

 

[sparkyv]

Sparky,

I don't think you should be connecting the neutral to the inverter's chassis. The whole point of one of those steps is to isolate it from the chassis. Remember fault grounding is seperate from earth grounding. Fault grounding is providing a path back to the source, which would be the inverter, not the grid.

I'm not totally sure with your scenario, but ya you should never hookup the neutrals to the house's panel when off gird. But I did as described by the manufacturer, which bonded the neutral to ground at the inverter. I also run a few transfer switches and have had no issues running this way since the original post.

The way I understand it is , unless there's a fault, the grounds are attached to the chassis of the device at the other end, so even though they're bonded to neutral, they cannot complete a circuit, unless their in a faulted state, which is the whole reason for having them.

I've used these, which do have the grounds connected, but does switch the hot/neutral wires. if that helps.

https://www.amazon.com/Xantrex-8080915-PROwatt-Transfer-Switch/dp/B004S5Y158/ref=sr_1_5?crid=2LWLR06DB5OBM&keywords=automatic+transfer+switch&qid=1654790466&sprefix=automatic+transfer+switch%2Caps%2C96&sr=8-5

Thanks for your response. One thing I'm not sure is . the yellow (ground ) is connected to the chassis of the inverter, so bonding the black(neutral) to yellow the same as bonding neutral to ground at the inverter? What is the part about the blue wire inside the inverter?
My neutrals are not connected house to inverter but all grounds go back to house main panel. including the inverter chassis.
I am using the Moes auto transfer switch which have neutrals separated.

 

[sparkyv]

Sparky,

I don't think you should be connecting the neutral to the inverter's chassis. The whole point of one of those steps is to isolate it from the chassis. Remember fault grounding is seperate from earth grounding. Fault grounding is providing a path back to the source, which would be the inverter, not the grid.

I'm not totally sure with your scenario, but ya you should never hookup the neutrals to the house's panel when off gird. But I did as described by the manufacturer, which bonded the neutral to ground at the inverter. I also run a few transfer switches and have had no issues running this way since the original post.

The way I understand it is , unless there's a fault, the grounds are attached to the chassis of the device at the other end, so even though they're bonded to neutral, they cannot complete a circuit, unless their in a faulted state, which is the whole reason for having them.

I've used these, which do have the grounds connected, but does switch the hot/neutral wires. if that helps.

https://www.amazon.com/Xantrex-8080915-PROwatt-Transfer-Switch/dp/B004S5Y158/ref=sr_1_5?crid=2LWLR06DB5OBM&keywords=automatic+transfer+switch&qid=1654790466&sprefix=automatic+transfer+switch%2Caps%2C96&sr=8-5

Thanks for your response. One thing I'm not sure is . the yellow (ground ) is connected to the chassis of the inverter, so bonding the black(neutral) to yellow the same as bonding neutral to ground at the inverter? What is the part about the blue wire inside the inverter?
My neutrals are not connected house to inverter but all grounds go back to house main panel.
I am using the Moes auto transfer switch which have neutrals separated.

 

[steviep19]

the blue wires connect the neural to the shell of the inverter.

Since we are connecting the ground and neutral they explained breaking that connection so the case of the inverter is not connected to neutral which could put voltage on the case making it a shock hazard

 

[sparkyv]

the blue wires connect the neural to the shell of the inverter.

Since we are connecting the ground and neutral they explained breaking that connection so the case of the inverter is not connected to neutral which could put voltage on the case making it a shock hazard

Got it. I contacted them also and they responded. But Their wording was a little ambiguous. "do not use yellow(ground) wire, if house neutral is connected to ground connect black neutral with it". The house neutral is connected to ground at the house main panel so I take it to mean connect neutral to a ground which goes back to main house ground. I think this would leave the inverter case unprotected if short to case. ??