Why do alternating curents having frequency greater than 700 hz dlcause no harm to human body?
Answers
see we know that ac current comes in positive peak and a negative peak when a body gets electric shock in dc there is direct ray of current due to which there is a damage in neurons conduction which is not so in case of ac as there is negative potential peak in current body can resides itself in this time
Even if the skin effect did kick in at 700 Hz for the human body, the current will then be passing through the outer layer of the body,ie. the skin.
Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor, and decreases with greater depths in the conductor. The electric current flows mainly at the "skin" of the conductor, between the outer surface and a level called the skin depth. The skin effect causes the effective resistance of the conductor to increase at higher frequencies where the skin depth is smaller, thus reducing the effective cross-section of the conductor. The skin effect is due to opposing eddy currents induced by the changing magnetic field resulting from the alternating current. At 60 Hz in copper, the skin depth is about 8.5 mm. At high frequencies the skin depth becomes much smaller. Increased AC resistance due to the skin effect can be mitigated by using specially woven litz wire. Because the interior of a large conductor carries so little of the current, tubular conductors such as pipe can be used to save weight and cost.