N-G bond my inverter. HELP!

[ClinicalScientist]

Hello Solar friends!
I’ve been a long time lurker and finally posting looking for for advice. As many people have posted: I am attempting to charge my EV from my setup, but am getting an insufficient grounding error. I know the EV charger is simply checking for a connection from ground to neutral (usually back at the panel for home systems). I know you can also create a bonding plug allowing this to work. I have an XYZ INVT 1500 watt pure sine inverter. After doing some research I became concerned about doing this with this particular inverter. It appears to me that both neutral and the HOT sides are putting out 60 volts with the ground simply a chassis ground. My questions are:

Can I safely bond the neutral to ground with this setup? I also run a GFCI with the setup.

Should I just return this inverter and get one where only the hot side is 120 volts and the neutral is 0v so I can bond the neutral safely?

Thank you so much for your advice in advance. Also note this system is not connected to shore power or a home system and is designed to be mobile.

 

[timselectric]

So, they both have a 60v reference to ground?
If that's truly how it's designed. Your only option is to use a small isolation transformer and bond the transformers output neutral.

 

[timselectric]

Have you tested this with a meter?

 

[Bud Martin]

1) Do you know if the Safety Ground is connected to the chassis or not? You can verify that with Ohm meter.
2) Did you contact XYZ to see if the Neutral can be bonded to safety Ground without damaging the unit?
3) Does the unit have AC outlet and and also AC output terminals?

 

[ClinicalScientist]

Thank you so much for the quick replies! I tested with a touch pen type tester first and all three lit up indicating voltage present. With the multimeter I get: neutral-hot: 127 volts. Neutral-ground 7 volts. Hot-ground 7 volts. Now I’m wondering if I have a faulty multimeter. I would like to test each terminal independently, but I do not know how with this setup as my ground is not bonded.

 

[ClinicalScientist]

1) Do you know if the Safety Ground is connected to the chassis or not? You can verify that with Ohm meter.
2) Did you contact XYZ to see if the Neutral can be bonded to safety Ground without damaging the unit?
3) Does the unit have AC outlet and and also AC output terminals?

1) The ground is attached to the chassis. I checked physically and with the ohm meter
2) for some reason this never crossed my mind. I will do that. Thank you!
3) it has two ac outlets, but no other AC access. No ac output terminals.

 

[timselectric]

You are going to have to check with the manufacturer. I wouldn't want you to damage anything.

 

[ClinicalScientist]

So, they both have a 60v reference to ground?
If that's truly how it's designed. Your only option is to use a small isolation transformer and bond the transformers output neutral.

Thank you so much for confirming this. I am going to get a new multimeter tomorrow and test again. I got scared at first from another post referencing this on reliable wzrleb inverters. And noticed mine is basically the same model with a different paint job. If there is no 60v reference to ground can I be sure this is not a split 60-60 to make 120 across?

 

[timselectric]

Truthfully, if you are not reading anything (or near nothing) to ground. Then the ground is floating. And you should be able to bond your neutral and ground together. But, i would still recommend that you contact the manufacturer to confirm.

 

[ClinicalScientist]

Truthfully, if you are not reading anything (or near nothing) to ground. Then the ground is floating. And you should be able to bond your neutral and ground together. But, i would still recommend that you contact the manufacturer to confirm.

Thank you again. I reached out to the seller and will report back with the response.

 

[Sky Noris]

I've got a simmular type of inverter - wzrleb 8KW inverter. It's not bonded inside the inverter so it must be bonded inside the panel. My solar system is completly off grid so I run a earth ground rod and everything. Before doing that I had a floating ground happening much like you would'd see watching David Poz's youtube review. Afterwards everything works great, no crazy voltage readings on netural.. Just 0 volts as it should. Here's a video that shows a floating ground happening.

- Voltage measurements are done at the 5 minute mark.

 

[ClinicalScientist]

I've got a simmular type of inverter - wzrleb 8KW inverter. It's not bonded inside the inverter so it must be bonded inside the panel. My solar system is completly off grid so I run a earth ground rod and everything. Before doing that I had a floating ground happening much like you would'd see watching David Poz's youtube review. Afterwards everything works great, no crazy voltage readings on netural.. Just 0 volts as it should. Here's a video that shows a floating ground happening.

- Voltage measurements are done at the 5 minute mark.

That’s very interesting. So before you grounded back at the panel you had a similar reading to the guy in the video? 60v neutral to ground? Thank you for the resource. I did ask the manufacturer if I could bond neutral to ground and they gave me a “no,” with no explanation or anything.

 

[timselectric]

A floating ground will read 50% voltage potential from almost always. When using a digital meter. I have worked with a lot of ungrounded delta industrial systems. You need an energy using tester to verify that it's not just potential that you are reading.

 

[Sky Noris]

If there is not a connection between the neutrual and ground it can't trip the breaker correctly. Because it has no path back to the source. When I was testing my inverter I found out it was not bonded.

 

[Sky Noris]

That’s very interesting. So before you grounded back at the panel you had a similar reading to the guy in the video? 60v neutral to ground? Thank you for the resource. I did ask the manufacturer if I could bond neutral to ground and they gave me a “no,” with no explanation or anything.

In all honestly I wasn't super concerned with the extra voltage. But I was worried about not having a bond anywhere. If power was applied to anything other then the neutral it wouldn't have a path back to the source. Any power would just flow to my earth ground. Now it has a single path back to the source. Previously I did read voltage on the neutral. Currently I read 0 volts and my power tester shows its grounded correctly.

 

[ClinicalScientist]

Thank you everyone for your help! I got a new multimeter and it was reading only 1 or 2 volts from neutral to ground, so I felt comfortable running the G-N bond. I did so behind a GFCI outlet encased in a 1 gang box. I didn’t run the ground back to the chassis figuring the gfi would trip if there was a short. Tesla charger is happy and so am I. On to the next challenge.

 

[CrazedFox1313]

Was reading this & it sounds very much like my issue as well.
My inverter would read the split 60v on each side.
But now reads the proper 120v hot & 0v on neutral after earthing the chassis ground to a proper installed ground rod.
After opening the inverter case & verifying the cassis, circuit-board & outlet/s all share same ground.
-
Also when I plug in my outlet tester it verifies that all is good.
Except when I try the EFCI test, then it’ll show open ground. I know it’s actually an isolated ground of sorts.
-
I was wondering if it’s alright to try bonding the Neutral to Ground, so I can have that last bit of safety ?

 

[timselectric]

Was reading this & it sounds very much like my issue as well.
My inverter would read the split 60v on each side.
But now reads the proper 120v hot & 0v on neutral after earthing the chassis ground to a proper installed ground rod.
After opening the inverter case & verifying the cassis, circuit-board & outlet/s all share same ground.
-
Also when I plug in my outlet tester it verifies that all is good.
Except when I try the EFCI test, then it’ll show open ground. I know it’s actually an isolated ground of sorts.
-
I was wondering if it’s alright to try bonding the Neutral to Ground, so I can have that last bit of safety ?

That depends on how your system is installed.
Do you have the grid connected to your system?
(In any way)

 

[timselectric]

But now reads the proper 120v hot & 0v on neutral

Assuming these are measurements to ground.
This is indicating that a N/G bond already exists.

 

[CrazedFox1313]

That depends on how your system is installed.
Do you have the grid connected to your system?
(In any way)

Apologies, it’s a modest 36VDC offgrid system.
It’s powering two EFCI outlets controlled by an light-switch for each.