Your Daily Safety Tip - The Effects of Electricity On Your Body The effect that an electric shock has on your body depends on the path that the current flows through your body. This is because the body components such as your skin, fatty tissues, muscles and bones have different resistances that vary with external influences, such as if your skin is wet or dry as wet skin has a lower resistance than dry skin, the amount of contact surface area and the contact pressure. The duration of the shock and the frequency of the voltage also determine the effect that the shock has on your body. The extent of the electric shock can vary from a tingling sensation to muscular contraction causing respiratory paralysis, ventricular fibrillation and the danger of severe internal and surface bums if not death. The effect will vary from individual to individual due to each persons unique physiology. The resistance of the skin can vary considerably for voltages below 50 volts and usually restricts the current to relatively safe levels. This is why electrical regulatory bodies classify Extra Low Voltage as 0 to 50 volts and do not require an electrical license when working on equipment operating up to 50 volts. The skins resistance can decrease rapidly for voltages above 50 volts and the current flow through vital organs such as the heart is often life threatening. The amount of current which passes through a body depends on the ratio of the voltage of the electricity to the resistance of your body. The smaller the resistance (or the larger the voltage), the more current passes through the body. As examples, an AA battery provides voltage of 1.5 volts, a car battery 12 volts and an electrical outlet 110 volts. The resistance (which is measured in ohms) of the human body can range from one hundred to one million ohms. Wet skin has a much lower resistance to current than dry skin. This is why electrical appliances warn against use while in the shower or bath; although the voltage of the appliance may not be sufficient to send large currents through a dry body, the same voltage may result in a very dangerous current in a wet body. If the resistance of a body is as low as 100 ohms, a voltage as small as 20 volts can lead to fatal currents. To put 50 volts into perspective, the wall receptacle in you house is 110/120 volts. Yet we take these for granted. Involuntary muscular contraction can occur at low levels of current and can lead to physical actions such as falling off ladders which will then lead to more serious physical injuries. One of the problems with electrocution is the failure for the victim to let go of the conductor or appliance because of muscular contraction, a factor that the rescuer must be always remember. The main cause of death from electric shock is ventricular fibrillation which is a condition of the heart in which bundles of muscles respond erratically caused by incorrect muscle timing, so consequently no blood is pumped, resulting in oxygen starvation to the brain which leads to death. Once ventricular fabrication is established it is extremely unlikely the normal operation of the heart will resume by its self The path of current through a body also determines the magnitude of the effect. Current entering a body wants to travel a path of least resistance and exit through the part of the body touching the ground. Because the heart is on the left side of the body, touching a live wire with your left hand means that the shortest path to the ground involves passing through your heart. If current travels through the right side of the body, the current is less likely to affect the heart. This is why medical first responder use a device called a defibrillator. Because the heart is made up from a lot of bunches of muscles, if a large DC voltage is applied directly to the body via the defibrillators pads, the muscles can be made to squeeze together for a period of time then released. The heart muscles are momentarily exhausted for a while, until hopefully the heart will attempt to resume its normal rate. It is absolutely imperative to seek medical attention after receiving a severe shock because internal parts that may have been burnt may release poisonous toxins after a few days which may kill the person even if they seem healthy. Being a trained first aider would be useful if you found a person lying on the floor unconscious from electrocution who was still touching the active appliance, as you would know how to assess and remove the danger, check for a response, clear the airway and check for breathing, check for circulation, carry out Expired Air Resuscitation and Cardio-Pulmonary resuscitation if required and call for help. If you are not a trained first aider leave the person alone and call for help. It’s all you can do at this stage. Shock Physiological Effects Electric Current 1 V - Threshold of feeling, tingling sensation. 5 V - Accepted as maximum harmless current 10 V - Beginning of sustained muscular contraction (Cant let go current.) 100 V - Ventricular fibrillation, fatal if continued. Respiratory function continues. 6000 V - Sustained ventricular contraction followed by normal heart rhythm. (defibrillation). Temporary respiratory paralysis and possibly burns.
Posted on: Thu, 05 Dec 2013 06:08:07 +0000
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