Resistance of the human Body

[mivey]

impedance of the load is typically much much smaller than the resistance of human body so whether you are in series or in parallel with the load makes virtually no meaningful difference.

My thought is that in the normal course of business, the parallel connection across the source tends to have a high impedance component through earth contact or similar whereas a series connection with a load has a relatively low impedance component (the load).

That is why I say a neutral shock tends to be worse as you tend to be in series with a low-impedance load through good skin contact (lower caution/awareness due to lower concerns about neutral safety).

A hot shock tends to include a high-impedance path such as earth contact, lower pressure contact, or some unknown multi-impedance meandering path back to the source (high awareness but accidental contact/path closure).

Of course a direct high-pressure contact from source hot to source neutral is worse than either of the two prior scenarios but these tend to be less frequent due to a higher awareness/caution level.

YMMV.

 

[edlee]

Now you've done it!
I am picturing a primitive tribesman building a crystal radio receiver out of bone.....

:lol: and here I always thought they used drums to communicate

 

[junkhound]

Now you've done it!
I am picturing a primitive tribesman building a crystal radio receiver out of bone.....

When a kid back in the early 50's, since we lived only about 5 blocks from an AM radio station tower, my ham radio uncle showed us how we could put a piece of galena (chipped from local high sulpher coal chunks in the coal bin in the basement) and a pencil lead and hold it just so between our teeth and hear the radio station! Better reception if one also had a silver amalgam filling.

 

[jcormack]

My thought is that in the normal course of business, the parallel connection across the source tends to have a high impedance component through earth contact or similar whereas a series connection with a load has a relatively low impedance component (the load).

That is why I say a neutral shock tends to be worse as you tend to be in series with a low-impedance load through good skin contact (lower caution/awareness due to lower concerns about neutral safety).

A hot shock tends to include a high-impedance path such as earth contact, lower pressure contact, or some unknown multi-impedance meandering path back to the source (high awareness but accidental contact/path closure).

Of course a direct high-pressure contact from source hot to source neutral is worse than either of the two prior scenarios but these tend to be less frequent due to a higher awareness/caution level.

YMMV.

That is one of reasons some sites or industries utilize high impedance grounding on three-phase systems - the additional resistance/impedance in the neutral to ground lowers the potential shock current / shock voltage hazard. A 554 ohm resistor between transformer neutral and ground on a 480 system limits the maximum ground fault current to 0.5 amp or less, and then add in the resistance of the human body + resistance of ground/earth path where you are and you have a somewhat safer system, but of course now require sensitive ground detection devices.

 

[mivey]

That is one of reasons some sites or industries utilize high impedance grounding on three-phase systems - the additional resistance/impedance in the neutral to ground lowers the potential shock current / shock voltage hazard. A 554 ohm resistor between transformer neutral and ground on a 480 system limits the maximum ground fault current to 0.5 amp or less, and then add in the resistance of the human body + resistance of ground/earth path where you are and you have a somewhat safer system, but of course now require sensitive ground detection devices.

The lesser of two evils perhaps.

 

[hourglass52]

Resistance

Resistance

Just wondering why, when I take the multimeter and put the negative probe on my belly button and touch my head and then my butt. The readings are the same???

 

[mivey]

Just wondering why, when I take the multimeter and put the negative probe on my belly button and touch my head and then my butt. The readings are the same???

The important thing is that it takes two readings rather than one.