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PowMr inverter has two grounds?

JoshPoget

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May 26, 2022
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I just finished building my 48 volt battery bank (EVE LF280K cells) and was going to hook up the inverter. However, the manual shows the AC Out only has Live and Neutral terminals and same with the print on the outer case where the grommet is at. However, inside where the terminals are at there is a ground terminal next to the AC Out Neutral. There is also a ground on out outer case which is what the manual says to use. My question is which ground do I use for a recepticle and can the inverter be used as a portable generator in a wood box where there is no ground pole or an RV frame? I read on some Amazon Q&A for this inverter that people are saying there is power on the live and neutral terminals and there is a grounding issue and others that say it is normal so I am not sure what is right here. Any help would be appreciated, it is the 5000 watt 120V version (model: POW-LVM5K-48V-H).
 
I read through the manual. It’s pretty clear the instructions are to ground the external ground lug.

You can test with a multimeter if the AC out neutral is connected to the case grounding lug. Ultimately if you have a neutral ground link in your incoming AC there should be the same basis of the invertor is supplying power in the absence of AC grid supply
 
Thanks for the quick reply. The manual also doesn't show the ground terminal inside the case next to neutral. It seems this was added recently and maybe the manual wasn't updated. With the inverter off I show continuity between the ground terminal and neutral terminal and same if I test between the neutral and ground on the outside of the case but no continuity between the ground terminal on the inside and the ground terminal on the outside. Also I will be hooking up my inverter gas backup generator to the AC in which brings up another question if that is ok since it doesn't have a bonded neutral.
 
Thanks for the quick reply. The manual also doesn't show the ground terminal inside the case next to neutral. It seems this was added recently and maybe the manual wasn't updated. With the inverter off I show continuity between the ground terminal and neutral terminal and same if I test between the neutral and ground on the outside of the case but no continuity between the ground terminal on the inside and the ground terminal on the outside. Also I will be hooking up my inverter gas backup generator to the AC in which brings up another question if that is ok since it doesn't have a bonded neutral.
I would ignore that inside ground. If you have case bonded to ground and neutral boned to ground. Your good to go

If your generator is the power source for your AC it should be neutral tied
 
Ok, so if I power on the inverter and it has 120v on live and neutral and same on the generator I am good to go? If the generator doesn’t then should I create a neutral bonding plug and put it in one of the generator outlets?
 
Ok, so if I power on the inverter and it has 120v on live and neutral and same on the generator I am good to go? If the generator doesn’t then should I create a neutral bonding plug and put it in one of the generator outlets?
There should be no potential between neutral from any power generator and your system protective earth line. ( unless you have a peculiar desire or need for floating AC )
 
I have seen people with inverter generators like mine that get a grounding error when trying to charge a Tesla for example so they have to create a neutral bonding/jumper plug and put it in one of the outlets on the generator to get around this. Are you saying the generator needs and earth grounding rod?
 
I have seen people with inverter generators like mine that get a grounding error when trying to charge a Tesla for example so they have to create a neutral bonding/jumper plug and put it in one of the outlets on the generator to get around this. Are you saying the generator needs and earth grounding rod?
Ev car charging systems have a requirement to measure ground loop impedance. Typically earth rod based grounding will fail such tests as the earth loop impedance is too high. In fact here the EV charge installers will not install where only earth rod grounding is detected.

You have two scenarios

(A) you have a grid feed where neutral is bonded to earth wire typically at the premises grid entry point. This is the more modern process. No earth rods are used.

In this case any grid tied invertor or generator should simply have its neutral bonded to its earth.

(B) you have no grid feed and hence no premises earth neutral bond

Now you need to establish a local earth. This requires an earth rod. Again all generators should be bonded to earth and neutral bonded.

Of course if you never had a grid feed your house should have a ground rod based earthing system.

What you don’t want is a grid tied neutral earth bond AND a earth rod also connected as thus is a risk of the neutral earth bond fails elsewhere in the grid system. Your earth rod could end up carrying your neighbours fault currents.

Hence if your invertor or generator are being used independently of the grid then you need to establish a local ground and connect the generator neutral to it.

( of course small gennys like the little Hondas don’t bother with that , they run floating AC)
 
My 2 champion 3500 watt gens have a screw on the front and says floating neutral. I use that screw on the front for bridging the 2 gems to the 50 amp combiner Champion wells. So no grounding rod needed in this case?
 
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My 2 champion 3500 watt gens have a screw on the front and says floating neutral. I use that screw on the front for bridging the 2 gems to the 50 amp combiner Champion wells. So no grounding rod needed in this case?
Many small generators run floating. It’s like an extension lead.

An all house unit is different
 
I would ignore that inside ground. If you have case bonded to ground and neutral boned to ground. Your good to go

If your generator is the power source for your AC it should be neutral tied
BE CAREFULL!!! Consult with an Electrician if you have doubts, "case or chassis" ground is not the same as A/C ground, you can't ignore the A/C ground and rely on the case ground, they both need to be connected, separately of course: A/C ground needs to go to your breaker panel and tied to the grounding system of your house A/C.
Case or Chassis ground needs to go to a local ground point in the area of the equipment installation, not related to the house A/C.
 
I opened the inverter case and found the ground terminal just has a wire going to the case inside so it is the same as the outside terminal. There is no continuity between ground and neutral on the inverter so when I try to hook up the Tesla it gets an error. Can I jump the ground to neutral in the inverter until I add the generator to the setup? And if the subpanel in my rv is neutral bonded then the generator should stay as a floating neutral right?
 
BE CAREFULL!!! Consult with an Electrician if you have doubts, "case or chassis" ground is not the same as A/C ground, you can't ignore the A/C ground and rely on the case ground, they both need to be connected, separately of course: A/C ground needs to go to your breaker panel and tied to the grounding system of your house A/C.
Case or Chassis ground needs to go to a local ground point in the area of the equipment installation, not related to the house A/C.
Sorry that’s not right. You do not establish multiple grounds in normal domestic. Systems it can be dangerous

The internal lug is not mentioned on the manual and should be ignored
 
Ok, and what about this: Can I jump the ground to neutral in the inverter until I add the generator to the setup? And when I add it to the RV I have read that the panel inside an RV is not neutral bonded so should I use the jumper in this case as well since the generator is a floating neutral? Or only use a jumper if I need to charge the Tesla or use power tools on extension cords?
 
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Sorry that’s not right. You do not establish multiple grounds in normal domestic. Systems it can be dangerous

The internal lug is not mentioned on the manual and should be ignored
Maybe I did not put it in the right context, I just review the manual page 14:1663180523995.jpeg

and page 15:
1663180553470.jpeg

I apologize for the misunderstanding, you are right.
 
Sorry that’s not right. You do not establish multiple grounds in normal domestic. Systems it can be dangerous

The internal lug is not mentioned on the manual and should be ignored
base on the manual, the internal lug is for A/C input only.
 
The manual must not be updated, see my picture with the additional ground terminal that is on the AC Out side. The outside case label was also not updated, it just says L and N but you can see there is a ground terminal there that has a wire to the case and the label inside shows the AC Out ground.
 

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The manual must not be updated, see my picture with the additional ground terminal that is on the AC Out side. The outside case label was also not updated, it just says L and N but you can see there is a ground terminal there that has a wire to the case and the label inside shows the AC Out ground.
Looks like they change the setup, I'll just connect all the A/C output and Ground to this terminal and not the outer. Also check if there is a ground/neutral bond at the inverter, just to be on the safe side.
 
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