Wet Location Body Resistance

mapj1:

If you go back far enough in old regs, the maximum accessible touch voltage that is normally 50V, used to be set to 25 in damp or conductive locations, suggesting an assumed halving of the body resistance.


Of course in reality getting a person wet only alters their surface resistance, the moisture levels of internal organs is not significantly affected. Therefore the effect of being coated in sweat or sea water is more akin to a dry contact over a larger contact area, but as the entry and exit wounds indicate, most of the heat, and so most of the resistance, is where the current path breaks the epidermis.

Once charring starts the resistance drops sharply, by providing cooling and improving the contact, water may reduce this surface burning effect at the penalty of a higher initial current. None of this is good.

Mike.

Thanks :) 




Any idea how this translates into a disconnection time? 


Table 41.1 seems to be based on a 0.8 multipler?

mapj1:

If you go back far enough in old regs, the maximum accessible touch voltage that is normally 50V, used to be set to 25 in damp or conductive locations, suggesting an assumed halving of the body resistance.


Of course in reality getting a person wet only alters their surface resistance, the moisture levels of internal organs is not significantly affected. Therefore the effect of being coated in sweat or sea water is more akin to a dry contact over a larger contact area, but as the entry and exit wounds indicate, most of the heat, and so most of the resistance, is where the current path breaks the epidermis.

Once charring starts the resistance drops sharply, by providing cooling and improving the contact, water may reduce this surface burning effect at the penalty of a higher initial current. None of this is good.

Mike.

Thanks :) 




Any idea how this translates into a disconnection time? 


Table 41.1 seems to be based on a 0.8 multipler?