It is the current not the voltage that can injure or kill
I just had to say something about homemade e-stim devices. Be very careful and know what you are doing. Before I retired I taught electrical safety all over California and Nevada and to some very large companies. Here are some basic facts that you can think about. There is a lot more to it than only what I am posting here but it should give a lot of you a better understanding of what electrical current can do to a body. The let go threshold for electrical current is about 10 mA (that is milliampere). The ground fault circuit interrupter (GFCI) like the one in your kitchen, bathroom or outside plus operates at around 7 mA. For undamaged clean skin the maximum live voltage that you can touch is below 50 volts. Usually the skin resistance is high enough that it will insulate you from and current at 50 volts or lower. That is in perfect conditions. (The classes I taught were OSHA qualified and usually were 6-8 hours in length.) So there was a lot to talk about. Anyway, below is a list of current levels and what could happen to your body if exposed to those currents.
An electrical current at 1,000 volts is no more deadly than a current at 100 volts, but tiny changes in amperage can mean the difference between life and death.
Effects of Amperage on Electrical Shock
Different amounts of amperage affect the human body in different ways. The following list explains some of the most common effects of electrical shock at various amperage levels. To understand the amounts involved, a milliampere (mA) is one-thousandth of an ampere or amp.
A standard household circuit that supplies your outlets and switches carries 15 or 20 amps (15,000 or 20,000 mA).
1-10 mA
Little or no electrical shock is felt.
10-20 mA
Painful shock, but muscle control could be lost.
20-75 mA
Serious shock, including a painful jolt and loss of muscle control; victim cannot let go of wire or another source of shock.
75-100 mA
Ventricular fibrillation (uncoordinated twitching of ventricles) of the heart can occur.
100-200 mA
Ventricular fibrillation occurs, often resulting in death.
Over 200 mA
Severe burns and severe muscle contractions occur. Internal organs can be damaged. The heart can stop due to chest muscles applying pressure to the heart, but this clamping effect can prevent ventricular fibrillation, greatly improving the chances of survival if the victim is removed from the electrical circuit.
There are some very ugly photos of the results of electric shock out there and if you have the stomach for it, search for electrical shock photos online. If you have questions, please don't hesitate to contact me.