Generally everyone fears receiving an electrical shock, quite simply because the instance can be distressing, physically harming and in some cases fatal.
An electric shock in humans comes about when the human body or parts thereof become/act as an electrical conductor. Fundamentally, the human body comprises mostly a saline solution, i.e. salty water, and since salty water is a fairly good conductor of electricity, so is the human body.
The key parameter when evaluating the severity of an electrical shock is ‘electrical current’ since electrical current constitutes a flow of electric charge, i.e. the movement of subatomic particles.
A further key parameter to consider is electrical voltage, since akin to the flow of water through a pipe (electrical current flowing through a conductor), electrical voltage can be considered akin to water pressure that stimulates water flow.
So given that the conductivity of the human body remains constant, electrical current flow will increase as electrical voltage increases.
The kinetics of physical movement of muscles within the human body comes about due to small electrical impulses (electrical current) conveyed and injected into muscles. So when the human body is inadvertently injected with ‘stray’ electrical current as during the course of an electrical shock, muscles react in a way to oppose or override those electrical impulses conveyed by the human brain. In other, more simple terms muscle movement becomes spasmodic.
IEC 60479.1 sets out the magnitude and format of electrical current that, when injected into a human body, those physiological effects an electrical current will bring about over a period of time.
To simplify, an electrical current of 50 milli-amperes, i.e. 50 thousands of one (1) Ampere, will over a period of one (1) second provoke pathophysiological effects such as cardiac arrest, breathing arrest, burns or other cellular damage.
Given analysis of the diagram and table below we can also comprehend other pathophysiological effects relative to injected electrical current and time.
In conclusion, no one wants to be the receiver/victim of an electrical shock, so I hope the latter may explain be helpful and indicate how dangerous electricity is.
Eur Ing Dr Robert Brown (Robert) is the Executive Director of Fraser George and Associates Limited and is a Consultant and Forensic Engineer in the fields Electrical Electronic and Control Engineering.
Robert is an accomplished professional Expert Witness having prepared and presented many court compliant reports and presented oral evidence within the High Court, Crown Courts and County Courts.
For further information please contact Robert via;
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