Question about capacitors and capacitor banks

[tim.hall53]

Hi,

I am pretty new to electronics and want to make sure I don't do anything dumb.

Could someone please tell me what is the smallest capacitor or capacitor bank that could be fatal?

Thanks!

 

[KerimF]

What harms our body is the electrical current (generated by a voltage source) that can pass in our biological tissues. I guess it is in the range of a few milli-ampers.

Time also plays an important role during which a current follows a path in the body and its limit depends on the path (like through heart for example) and the current amplitude.

I think AC and DC current have different limits while AC is sensed easier.

As you know current could be calculated:

For DC:
I = V_source / R_total

For AC:
I = V_source / Z_total

My friend (a technician) touches the mains hot line (220V, 50Hz) to feel if it is dead or not. Obviously before doing this, he checks that his shoes are well dry and his hand as well. I mean, as long R_total (or Z_total) of the current path including of the body is high enough, there is nothing to fear.

I am afraid you need to search for the current/time limits to get more professional advices.

Zc = 1 / ( 2 * pi * freq * C )
But there is also the possible inrush step current (this depends on the rest of the circuit and its state).

 

[Sloth]

Hello,

With high voltage even small energies could be fatal. Meaning that you only need a small capacitor. Heart "control pulses" are very low energy too. So distracting them doesn't need much of energy. Using low voltages will keep you safe, as they hardly penetrate skin and skin impedance keeps currents low.

And KerimF, you might advice your friend to get a voltage pen or touch other wires with the L-wire to see if it's live or not. That is if the friend is any dear to you.

 

[tpetar]

I dont think that small HV (220V-300V) can kill healthy adult person, but can give good electro-shock for remembering, in contrast of that big HV can be fatal. I think that is bigger chance for someone to die is if eat toxic material from small electrolytic capacitors. Bigger capacity is different story. Even small voltage 1F or few farads can be dangerous when make sparks on metal.

Capacitor Testing, Safe Discharging and Other Related Information
https://www.repairfaq.org/sam/captest.htm

 

[KerimF]

Thank you Sloth for your care. I used always telling him to stop this bad habit ... now he is 60 years... Do you think there is a chance that he uses always his voltage pen? Sometimes I feel that he enjoys being electrified at low dose

 

[Sloth]

Maybe that keeps his heart still running!