voltage showing between inverter's earth and neutral

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ketoneenergies

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Oct 22, 2018
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voltage of 20v is showing between inverter's earth and neutral when only battery is connected. when input, output and earth connection is made voltage is showing 120v between earth and neutral without load. With load voltage is showing 55v between earth and neutral.
 

Roland W

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Oct 9, 2017
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I have already made this video for you :)

 

italianuser

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Feb 25, 2020
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oh my @Roland W ! Very good explanation. Soon I'll make the connections to the OffGrid Inverter and I already know (from some tests I did last year) I have 50-55V between ground and hot. My building is not grounded to earth so I don't have a ground bar in the Grid Panel (the box is at the entrance of the house); I only have all ground wires in the house connected together (but they don't discharge anywhere). I suppose it's not the best scenario... :whistle:
 
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Roland W

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Oct 9, 2017
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137
oh my @Roland W ! Very good explanation. Soon I'll make the connections to the OffGrid Inverter and I already know (from some tests I did last year) I have 50-55V between ground and hot. My building is not grounded to earth so I don't have a ground bar in the Grid Panel (the box is at the entrance of the house); I only have all ground wires in the house connected together (but they don't discharge anywhere). I suppose it's not the best scenario... :whistle:

In older European houses, plumbing typically is made with steel pipes. You could get a Ground there. It is many times made like that. Would that be a possibility in your house?
 

floydR

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Aug 23, 2017
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Many houses in the US are also grounded via the plumbing usually on an pipe exiting/entering the house grounded to cast iron pipes/copper
Later floyd
 

italianuser

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Feb 25, 2020
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@Roland W @floydR Attaching ground wires to water pipes, yes, I've seen this in many houses. Although it works I'm quite sure it's illegal in Italy, I'll check it. That's because people got electric shock touching the pipes. If they don't create the ground connection for the building I suppose I'll have to do without:censored:

This morning I did some measurements, just to see what's going on, strange numbers come up! Nothing is switched on (no TV, no washing machine, nothing), a part from the fridge, my notebook, a lamp, a couple of cell chargers and three Liitokalas LOL. Monitoring says I'm consuming around 1A, multimeter says 238V.

Hot - GroundNeutral - Ground
Lab, multiplug extension connected to another multiplug extension9V7V
Lab, wall plug86V1V
Bathroom, wall plug120V105V
Kitchen, wall plug (open space)140V85V
Balcony, wall plug where I'll connect Offgrid Inverter (open space, about 10mt / 32ft distant from kitchen)140V85V
 
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Roland W

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Oct 9, 2017
Messages
137
@Roland W @floydR Attaching ground wires to water pipes, yes, I've seen this in many houses. Although it works I'm quite sure it's illegal in Italy, I'll check it. That's because people got electric shock touching the pipes. If they don't create the ground connection for the building I suppose I'll have to do without:censored:

This morning I did some measurements, just to see what's going on, strange numbers come up! Nothing is switched on (no TV, no washing machine, nothing), a part from the fridge, my notebook, a lamp, a couple of cell chargers and three Liitokalas LOL. Monitoring says I'm consuming around 1A, multimeter says 238V.

Hot - GroundNeutral - Ground
Lab, multiplug extension connected to another multiplug extension9V7V
Lab, wall plug86V1V
Bathroom, wall plug120V105V
Kitchen, wall plug (open space)140V85V
Balcony, wall plug where I'll connect Offgrid Inverter (open space, about 10mt / 32ft distant from kitchen)140V85V

Mama mia, those numbers are straight out of a horror script. Don't electrocute yourself there! Grounding over water pipes is banned, there where the city has already changed their water supply from metal to plastic pipes. You need to get a proper grounding from somewhere. So dangerous :(
 

italianuser

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Feb 25, 2020
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:sick::sick::sick: Aww... I really would make the whole circuit again... it would cost me around 2000€. I never had any real problem during the last ten years (when it was done), and I added MCBs (they do work) and RCBOs (testing them every month) on both floors. I will consider having it fixed, how the say in Italy "if I have 2000€ falling out of my pocket" (extra money!).

For the grounding... the whole roof was made new some years ago, it's based on a big 400m2 metal grid, I might give it a try. Just as a test to see if measurements get better, nothing more.
 

MBF Dan

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May 14, 2021
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:sick::sick::sick: Aww... I really would make the whole circuit again... it would cost me around 2000€. I never had any real problem during the last ten years (when it was done), and I added MCBs (they do work) and RCBOs (testing them every month) on both floors. I will consider having it fixed, how the say in Italy "if I have 2000€ falling out of my pocket" (extra money!).

For the grounding... the whole roof was made new some years ago, it's based on a big 400m2 metal grid, I might give it a try. Just as a test to see if measurements get better, nothing more.
You have to get to the earth with grounding the roof won't help it will infact just make the risk more as your entire roof will rise the the floating voltage. You need to get a discharge path into the earth people get killed by floating voltage over 40 volts if I remember the OSHA safety standard correctly. This really isn't an optional expense it is one of those things you can't afford not to have right.
 

prepared1

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Jan 17, 2021
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I spend a lot of time working on old buildings. I've come to accept that you just cannot know what was modified in that building during its' lifespan. Like people cutting into copper plumbing and inserting a section of PEX tubing somewhere. Or, removing conduit, and converting to Romex. You just cannot rely on a ground in those situations. A copper ground rod costs about $20, and some bare copper, or green coated copper wire, pound the rod into the ground somewhere away from the rest of your electrical system, use a good bronze clamp on the rod, and be done with it.
 

italianuser

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Feb 25, 2020
Messages
361
@MBF Dan Most of the buildings here made before 1990 or so don't have any proper grounding! I asked the other people here in my building but seems like nobody interested in spending a penny for grounding.

@prepared1 I'm at the 5th floor of a building in the middle of other buildings, there's a river under the street. The proper procedure, more or less, would be to ask a permission to the counsel to do the job, rent a company that will do the project, have it signed by an engineer, do the drilling and cabling; they will send a team over for, I'm guessing, a week and do everything. But how I was saying to MBF the other 10 families here aren't easy to convince. Plus they say "if nobody had injuries since 1950 why should we spend money" wth...

I'll ask our condominium manager again to see what he says about costs for this operation.
 
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