Also, like you mentioned, the heart is controlled by electric pulses and repeated pulses of electricity can throw this off quite a bit and cause a heart attack. However, I don't think that this is unique to alternating current. I read once about an unfortunate young man that was learning about electricity and wanted to measure the resistance of his own body.
He took a multimeter and set a lead to each thumb. By accident or by stupidity, he punctured both thumbs with the leads, and the small I imagine it to be 9 V battery in the multimeter caused a current in his bloodstream, and he died on the spot.
So maybe ignorance is more dangerous than either AC or DC. Direct current DC , because it moves with continuous motion through a conductor, has the tendency to induce muscular tetanus quite readily. Alternating current AC , because it alternately reverses direction of motion, provides brief moments of opportunity for an afflicted muscle to relax between alternations.
Thus, from the concern of becoming "froze on the circuit," DC is more dangerous than AC. However, AC's alternating nature has a greater tendency to throw the heart's pacemaker neurons into a condition of fibrillation, whereas DC tends to just make the heart stand still. Once the shock current is halted, a "frozen" heart has a better chance of regaining a normal beat pattern than a fibrillating heart.
This is why "defibrillating" equipment used by emergency medics works: the jolt of current supplied by the defibrillator unit is DC, which halts fibrillation and gives the heart a chance to recover.
This is because the voltage rating is the average of the oscillating voltage after taking all positive. Realistically statistically speaking, AC is more dangerous that DC. The DC voltage that we are most likely to encounter is 12 DC in our vehicles , and it is very unlikely to kill us. Sign up to join this community.
The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why is AC more "dangerous" than DC? Ask Question. Asked 8 years, 7 months ago. Active 2 years, 6 months ago. Viewed k times. Same is the case i. AC Currents and voltages are three to five times more dangerous than DC having the same level of voltage. In case of DC voltage and currents, It causes a single convulsive contraction a jerky and uncontrollable process in which muscles become shorter and tighter which pushes the victim away from the DC current or voltage source they touched.
In case of AC voltage and currents, it causes tetany a condition marked by intermittent muscular spasms or extended muscle contraction which leads to freeze the victim or part s of the body touching the AC voltage or current source. In that cases, defibrillating equipment which supply DC units to halt the fibrillation and bring back the heart to the normal condition are used as emergency medical service. Generally, the final decision depends on multiple factors like, human body resistance, wet or dry skin or place, thickness of the skin, weight, sex, age, level of current and voltages, frequency etc.
If we consider the minimum level of AC and DC voltages, 50V AC in Dry condition and 25V in humid and wet places and up to V DC are considered safe in case of direct or indirect contacts with electrical installations. Same is the case for current, i. The following table shows the story of AC and DC and its effects on human body. But Voltage is must to drive the Current. Amperes are responsible for electrocution, Not the Volts. Following are some reasons showing that AC is more dangerous than DC.
RMS and Peak Value. It is the effective or RMS Voltage. The equation of this alternating current is. Putting the values and solving for Voltage:. In short, More DC voltage or current is needed to induce the same hazardous effect as AC voltage and current. A victim body acts an insulating medium between the live wire and ground leading to capacitance.
But we know that a capacitor blocks DC while AC can pass through it. Resistance in DC:. Now resistance in AC also known as impedance. Rapidly changing voltage allows more current to pass through the body. There are arguments in favour of both AC current and DC current. These arguments are based on experiments and studies carried out on human beings including men and women and industry professionals who have experience of working with both the types of currents.
Victims who have experienced the electric shock with DC current says that they are unable to pull their hand back because DC current flows continuously.
This effect is similar to an electric doorbell supplied with DC current. Hence, it is believed that the DC current shock is more dangerous. Whereas, in the case of AC current, the person experiencing the electric shock can pull their hand back as the current goes to zero.
Hence, it is believed that the AC current shock is least dangerous than DC current. When the person is experiencing an electric shock, the focus of that person is to get rid of it and save the life. What is happening internally to the muscles cannot be known. According to Charles Dalziel experiments on men and women, muscles contraction is continuous in case of an electric shock with DC current. Whereas in the case of AC current, a person experiencing electric shock undergoes a series of muscle contraction.
Series of muscle contraction causes very severe damage to the muscles. Due to the capacitive behaviour of the skin coming in contact with the current carrying conductor, more current can pass through the body if the voltage is rapidly changing. Studies have shown that twofold of increase in the voltage increases sevenfold increase in the current.
More DC current is required to produce a similar effect as of AC current. These arguments are not only based upon experiments being carried out on men and women but also have been studied medically. Hence, the argument in favor of AC current holds the truth. Well, one should not be afraid of electricity, but one must remember that both AC current and DC current can be dangerous to the human body and safety measures must be taken into the consideration when working with any of them.
Krunal Shah is a passionate educator and career-counsellor with experience as an Entrepreneur. Currently, he is working as Director of Subodh Tech Private Limited, where he is involved in providing job-oriented training and Engineering Consultancy. Informative and interesting article. If author includes the results and after effects into article, it could be more better.
During my working day when I was in middle east my friend suffering from knee rheumatic disease he took the AC and put it on his knee I have seen his leg shaking but nothing happen to him and his rheumatic knee feels ok. Thanks to Mr. Krunal Shah and EFY for wonderful article. I never come across such a beautiful article on electric shock. But this article is very good.
It is very interesting article. Your explanations has a logical flow which makes me read it very comfortably. Thank you so much!
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