Why would you die if you jumped into an electrically charged pool of water?

Question

I was watching Syriana in which a swimming pool light has failed so the water is charged with electricity. This is analogous to when people drop toasters in swimming pools. The thing is that I would have thought the electricity would take the easiest route to earth, which would only be you if you were still touching the sides and the pool was insulated from earth itself. So why does the electricity travel through the higher resistance material (the body)?? Or if it doesn't, how does it kill people??

Answer 1

It’s worth exploring the difference between the key electrical concepts; charge, voltage and current. First of all - charge per second (current) only flows between an electric potential difference (voltage). The current flowing in any material is directly proportional to the voltage and inversely proportional to the resistance. Volts / Resistance = Amps. (divide by the volts the resistance to get the Amps).

Forget the pool for a moment, take the simple case; if for example, you were unfortunate enough to touch a live conductor at 100V. Your resistance under wet conditions can be as low as 1000 ohms which under 100V can produce 100mA.

Actually we are saying that there is a POTENTIAL of 100V at the point you touch a live conductor and a potential of zero volts on the ground. The potential DIFFERENCE is 100V - 0V or 100V. Note, if you were standing on a 100V wire whilst touching another 100V wire then THEORETIACLLY no current would flow (100V - 100V) = 0. NEVER EVER TRY THIS - there are other effects which occur in practice which are likely to kill you.

If there is a sufficient potential difference across your heart (say) then sufficient current will flow to disrupt the pattern of electrical activity which keeps your heart beating. Instead of all the tiny muscle cells in your heat contracting together, they start to do their contracting out of sequence. This process is called fibrillation. Left untreated, there will be insufficient blood flow to your brain, which will then die of oxygen starvation. The current required to flow through a heart to cause this effect is (from memory only 50 thousandths of an amp (50 mA). The actual effect on the human body will depend on how much current flows. In extreme conditions, severe burning of the organs can result from the electrical heating effect as the current passes through them. See the reference for the effects.


If the water didn’t conduct (very large resistance ) you would be safe because the Resistance would be very large - and you are dividing 100 by a very large number - so no current. Thankfully, this is the case with air - which is why you are not killed by overhead power lines!

But the water does conduct! Some electricity will flow directly to earth and some will flow through the water. In fact, there will still be an electric potential difference in the vicinity (probably the whole pool) of the exposed conductor. Consequently, some of the electricity will flow through the pool water, some will flow through the person in the pool, some will flow through to earth.

The comment about the fuse may not be correct. There may not be sufficient current flowing in the water to blow a fuse, but sufficient to kill you. The correct approach is to use a residual current device. (RCD) This measures very precisely the currant flowing into the pool lights and out again. If any current is leaking to earth, the RCD detects the imbalance and trips the circuit within a few milliseconds. Always use one when mowing the lawn! The website listed explains that injury is also dependent upon the length of time you are exposed to the current. Most RCDs will trip the circuit within a safe interval - if some of the current happens to be passing through you!

Hope this help

Answer 2

This wouldn't 'charge' the pool, leaving it with a large net positive or negative charge. But it could cause a current flow within the pool. Your body would have a lower resistance than the pool water because of all of the salts and other electrolytes in your body. That might not be true in the ocean or in the Great Salt Lake. So it's likely that enough of the current will flow through you to cause damage.

Answer 3

It would kill you because the electricity would should through your body and give your heart a huge jolt,
Your probably thinking "You have to touch the floor for it to hurt to complete the circuit" but water conducts electricity, and the water in the pool reaches the bottom which is connected to the floor completing the circuit.

Answer 4

Water is a horrible conductor of electricity so the second something enters the water the electricity tries out that object next.

I know it's an overly simple explanation and some may disagree with what I say but screw you all, I barely passed GCSE Physics and that was 16 years ago so forgive me for not being scientific enough for you cruel bastards.

Answer 5

Electricity runs through water so yes, i think it'd definitly kill some body, depending on the charge of course

Answer 6

I don't think so, if you jumped in there would be nowhere for the current to flow but as soon as you touched something at a lower potential you'd die as you would complete the circuit.
PS I wouldn't like to try it!

Answer 7

It wouldn't do much to you if the thing is wired properly. You may suffer a bad burn, but the fuse in the fuse box will blow out before any bad burns would happen, unless you put a big fuse in instead.

Answer 8

The currents shoot through the water molecules

Answer 9

Just half an amp can disrupt the nerve-impulse which controls the heart, and similarly, our breathing mechanism.

Answer 10

the water is a liquid the body is a solid and the lightening has to earth and the only way to do it is through a solid.