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We always say that a low current can kill. However my knowledge of current is the amount of Coulomb. When that is explained, there is no mention of voltage level...

However, shouldn't voltage be important too? Do we consider a voltage of 120V because this is the voltage in common wire?

Let's make an extreme supposition.

Would 1A with 1 pV still be dangerous?

If so why? Coulomb are like particle as far as I understand, so if they have no energy, why would they be so dangerous?


marked as duplicate by Marcus Müller, Enric Blanco, Voltage Spike, Dmitry Grigoryev, winny Jul 10 '17 at 12:06

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  • \$\begingroup\$ With 1A @ 1 pV you'll be dead before the current starts, because you're made of superconductive matter. \$\endgroup\$ – Dmitry Grigoryev Jul 10 '17 at 11:54

It is the level of current that determines how dangerous electricity is when it flows into the human body. The level of current is determined by the voltage and the resistance of the path that the electricity is using to enter the body. Thus both voltage and current are important. Assuming the body's resistance is fixed, the current is proportional to the voltage. Low voltages (say below 40 volts) are usually considered reasonably safe because the resistance of the human body is high enough so that dangerous currents will not flow. House mains voltage (usually 120 or 240) is high enough that dangerous currents can flow. Your example of 1 pV and 1A would require a resistance so low as to be impossible given that wire resistances and the range of body resistances are orders of magnitude higher. As far as energy goes, again consider how much energy is being supplied by your mains voltage which is just a flow of current. By the way, a coulomb is a measure of charge and is not a particle.


Remember Ohm's Law - the current that can flow through your body depends on the resistance that the current is flowing through (your body's resistance, and any other resistances in series with your body) and on the applied voltage.

If you can somehow manage to get 1 Amp flowing through your heart with only 1 picoVolt you will be electrocuted - but your body resistance and other resistances are sufficiently high that 1 pV is highly unlikely to produce a harmful current (if might if you apply electrodes directly to the heart muscle, but I doubt even that would do it.)


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