DC Photovaltaic grounding- twice the current for a positive ground?

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mbrooke

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Why does a positive grounded system result in double the current flowing through the human body? I never knew this was possible. :dunce:
 

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mpoulton

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Location
Phoenix, AZ, USA
That doesn't sound accurate or logical at all. I downloaded the publication that's from, and it looks like those authors got their "understanding" of DC grounding from another article published in a different journal on the safety of 400V DC distribution in datacenters. I can't read that source without paying for it though. I can think of no reason at all that the amount of fault current would change based on the polarity of the system, or that one polarity would be more dangerous than the other, since there's no way to know in advance what direction the current will actually end up flowing across a victim's chest.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
That doesn't sound accurate or logical at all. I downloaded the publication that's from, and it looks like those authors got their "understanding" of DC grounding from another article published in a different journal on the safety of 400V DC distribution in datacenters. I can't read that source without paying for it though. I can think of no reason at all that the amount of fault current would change based on the polarity of the system, or that one polarity would be more dangerous than the other, since there's no way to know in advance what direction the current will actually end up flowing across a victim's chest.



Ok- phewww. Because I thought I was really lacking in electrical theory :lol: Then again I still wonder if there is any basis, as my understanding on electrical theory isn't complete.
 

jaggedben

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Northern California
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Solar and Energy Storage Installer
If you read it again, it doesn't say that twice the current flows. It says it 'seems' like this due to something called the 'heart-current factor.' I have no idea whether the latter is anything real but if it is it would be due to a characteristic of the heart and not the electrical source. Kinda sounds like BS to me but I'm not a biologist.
 

mpoulton

Senior Member
Location
Phoenix, AZ, USA
I just went over this in detail with a physician who happens to be an expert on the physiology of electric shock. He says it's a load of BS that doesn't make any sense. The heart-current factor refers to the proportion of the total current through the victim which passes through the heart. This does not depend on polarity. None of this depends on polarity. A DC shock in either direction is equally dangerous, all else equal.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
I just went over this in detail with a physician who happens to be an expert on the physiology of electric shock. He says it's a load of BS that doesn't make any sense. The heart-current factor refers to the proportion of the total current through the victim which passes through the heart. This does not depend on polarity. None of this depends on polarity. A DC shock in either direction is equally dangerous, all else equal.

Awesome! Thank you! :)
 
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