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This perhaps looks like 8th grade question. I have two different scenarios:

  1. I am handling an electrical appliance with dry hands.
  2. I am handling an electrical appliance with wet hands.

It is often said that "it is dangerous to touch appliances with wet hands because water is good conductor." However, if there is a complete circuit connecting the power supply to "me" and then to the ground (0 potential,) then the first scenario should be as bad as the second scenario since the equivalent resistance is almost the same in both scenarios.

If so, is this fact a myth? Since somebody asked for a reference: check the first paragraph of this 8th class textbook (NCERT, India)

IY4
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  • @MarcusMüller I read your answer to that question. You said that with wet hands resistance decreases. But why? It is a series circuit so resistance should only add up. – IY4 Oct 25 '21 at 09:08
  • Please provide a link to this quote: *It is often said that....* – Andy aka Oct 25 '21 at 09:14
  • @Andyaka Done. Please check. – IY4 Oct 25 '21 at 09:14
  • @IY4 if your life depends on sum resistance being 100 kΩ and not 10 kΩ, would you not want the body-ground and the conductor-body resistances *each* to be as high as possible? – Marcus Müller Oct 25 '21 at 09:25
  • In the UK, there are no wall switches in bathrooms for this reason; the light switch is either just outside the door, or ceiling mounted with a pull cord. –  Oct 25 '21 at 09:53

2 Answers2

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The appliance should be designed so that live conductors are not touchable. Touching the case with wet hands is not by itself a problem.

The problem is that water from wet hands may leak into the appliance and provide a conduction path from the live conductors to your hands. This can result in potentially fatal electric shock.

enter image description here

Figure 1. A hair drier switch. Image source (random): https://www.birthofbeauty.com/turbo-power-replacement-hair-dryer-switch.html.

Consider the switch on a hair-drier for example. The live conductors are not very far from the thumb activated lever or slide and in a poorly designed switch it wouldn't take much water to create a hazard.

Transistor
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The water is a good conductor is often said but it is wrong, because what conduct electricity in water are ions, in any case we don't know how much salt (condictivity) the water we are talking about have. We can assume that sea water is worst than rain water.

For the worst scenario, sure you have to be connected to ground if not no current will flow but we should distinguish between AC and DC.

I suggest to watch ElectroBoom, a youtuber that despite is comic plot on the videos explain very well the electrocuting process with real experiments.

gino
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  • I mean tap water which is a good conductor because it has ions in it. – IY4 Oct 25 '21 at 09:09
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    sure, I was depicting only the two estremes, a water with a good conductivity (sea) and one with a "poor" one (rain). Just for information there are others thing very dangerous, I remember a miner die because he was urinating and catch a damaged cable with the stream of urine. – gino Oct 25 '21 at 09:48