How many volts of electricity can humans with stand before even minimal damage is caused?

Question

This would be a shock to promote caution and allertness, as a warning more than punishment. PLEASE INCLUDE SOURCES if possible

Answer 1

The human body, because it is mostly water, is a relatively good conductor of electricity, except for the skin which is dry, which is a very poor conductor. Most of the damage caused by electrocution comes from burns, caused by the electric current heating the the material it is passing through, or from flash burns caused by arcing. Many of the burns occur where the current entered and left the body through the skin, because as I said the skin has a much higher resistance than the rest of the body, so it is heated much more. Deep burns are less common, but possible, especially if the the current is restricted to a small area, such as the fingers, arms, or legs. Under normal circumstances, a voltage of less than 200V is unlikely to cause a serious shock, unless the skin has been moistened.

Very high voltages have been known to cause nerve damage, as nerves conduct electricity slightly better, on average than the rest of the body, and have insulating, fatty sheaths. This is often the case with lightning strikes. It is thought that very powerful electric fields are able to cause damage to cells on a microscopic level; this is known as "microperforation."

Electric currents can cause unconsiouness and temporary seizures if passed directly through the brain. This is what happens in so called "Electroconvulsive Therapy," an archaic, but often effective treatment for some psychiatric disorders. This is where the patient is given a general anesthetic and muscle relaxant, and a tiny high frequency current is passed through the brain, inducing a small seizure.

Electric currents can stimulate muscles to contract. This is sometimes a problem with electrical workers, as the current makes them unable to let go of whatever they are holding on to. This is easy to avoid by wearing thick rubber gloves, or using hand tools that are specially insulated for electrical work, and using only one hand at a time to avoid completing the circuit.

Deaths from electrocution are nearly always due to cardiac arrest. A current density of about 100mA per square centimeter may be enough to stop the heart. Under normal circumstances this is difficult to achieve without voltages on the order of 2000~9000V, and without a conduction path directly through the heart. However it is possible to affect the heart using much smaller voltages and current, if the skin is moistened and/or the electric shock is applied directly to the heart, as in the case of medical defibrillators.

Answer 2

Hmm... this is indeed a tricky question, for the real value is only an approximation (furthermore, it differs for a direct current and for a alternating current). Assuming that it is a direct current, a man, can tolerate a current about 4.5 ~ 5.5 mA and for woman should be around 3.2 ~ 3.8 mA.

PS: For a further information, I've already enclosed an url link :).
PPS: I hope this helps :)