CrazyEngineers Archive
Old, but evergreen and popular discussions on CrazyEngineers, presented to you in read-only mode.
@aarthivg • 17 Jul, 2012 • 2 likes
The shock of an ac supply is attractive and more dangerous whereas shock of dc is less dangerous and repulsive. Why?
@Harshad Italiya • 18 Jul, 2012 I think AC Supply shock is less dangerous compare to same amount of DC Current.
@Anoop Kumar • 18 Jul, 2012 Yes DC is more dangerous, its depends on voltage.
Since we don't use DC more than 12v we think DC is less dangerous.
@rajasekhar266 • 18 Jul, 2012 dc shock is more dangerous than ac
@rajasekhar266 • 18 Jul, 2012 DC is more dangerous than AC. Because, AC varies from zero to maximum and then again to zero..In this way, AC puts jerks to a person due to continuous variations. On the other hand, DC is smooth, unvariable and continuous.
@Kaustubh Katdare • 18 Jul, 2012 AC puts jerks to a person due to continuous vibrations? - I'd like to hear more on this. 😨
@rajasekhar266 • 18 Jul, 2012 hand may be isolated from shock within that span of time because of zero voltage
@silverscorpion • 18 Jul, 2012 • 1 like ^^ I think what he meant was that in AC current, the voltage is continuously varying.

The severity of the shock you get depends on both the voltage that is applied and the current that flows through the body. That in turn depends on many things like the body resistance, time of exposure to the current, maximum current driving capacity of the source etc.. In general, 100 mA (milliAmps) of 50 Hz AC current is enough to kill. For DC, it seems to be about 500 mA.

The following is a table from here, that shows the various values of current and the effects produced..

[​IMG]

AC or DC, both can be equally dangerous. And also, the danger level of any particular voltage or current level depends on the actual power (V*I) that is acting upon the body. So, even 30V or 50V can be dangerous given the right conditions and low enough body resistance. It's better to exercise caution regardless of AC or DC..​
@agutulawy • 28 Jul, 2012 Hi I do think when we use same current fof AC and DC then Dc is much stonger than Ac because of Ac oscillating graph while DC is on a constant graph hence no complete of cct while in Ac you complete the cct
@varun191singh • 03 Aug, 2012 • 1 like see ac is more dangerous than dc because what we get supply is just the rms value of the voltage i.e 220v but its peak value is around 320v.so if u r going to touch a live wire u are gonna to get a shock of nett 320v not of 220v
@[Prototype] • 03 Aug, 2012
varun191singh
see ac is more dangerous than dc because what we get supply is just the rms value of the voltage i.e 220v but its peak value is around 320v.so if u r going to touch a live wire u are gonna to get a shock of nett 320v not of 220v
When you compare the equal magnitude of AC & DC, the DC is more dangerous. It being RMS or not doesn't matter. If you're saying 320V AC, then you compare it with 320V DC, in which, the DC is always more dangerous.
@Ramani Aswath • 03 Aug, 2012
The_Big_K
AC puts jerks to a person due to continuous vibrations? - I'd like to hear more on this. 😨
In the case of AC shock, physiologically the disorientation of the pulsatile shock can disorient the brain and prevent a person from with drawing from the source, leading to a greater damage. I do not know how a higher frequency shock would work. 50 Hz is a bad frequency for shocks.
Incidentally, I did get a massive shock from a high voltage (>2000V) RF source while developing a welding process for PVC. Fortunately for me, the frequency was so high that the current passed along the skin to the ground. It was scary to see the line of discharge from the electrode following my fingers even after I jerked back my hand. I did feel disoriented for a few minutes.
@Abhishek Rawal • 03 Aug, 2012 • 1 like I will go simple here, DC is more dangerous than AC !

why ? check waveform below :
[​IMG]

[​IMG]


IN AC, Voltage changes with respect to time ... so by mistake if your fingers been stucked in plug-hole .. scientifically u have a "milliseconds" of time to remove ur hands ... as u see AC voltage reaches zero twice a cycle and voltage is always fluctuating.
While, in DC current , voltage remains constant .. so u dont have any chance of saving your soul. 😁
@singh manvendra • 03 Aug, 2012 AC is more dangerous than DC.... Since our body fluids are ionic in nature, when you touch a wire carrying AC current, the polarity of your body in contact with the wire becomes same as that of wire. But then suddenly AC reverses the polarity...Unlike charges attract each other and this phenomenon repeats. So you will remain stuck with the wire.

However DC does not change the polarity so as soon as the polarity of your body is same that of the current (which happens in a fraction of seconds)....it throws you away (like charges repel each other).... although the shock will be more in case of DC but you may survive as the shock is momentarily..... But in AC you will be stuck with the wire as long as current flows
@graphite • 03 Aug, 2012
AC is more dangerous than DC.... Since our body fluids are ionic in nature, when you touch a wire carrying AC current, the polarity of your body in contact with the wire becomes same as that of wire. But then suddenly AC reverses the polarity...Unlike charges attract each other and this phenomenon repeats. So you will remain stuck with the wire.

However DC does not change the polarity so as soon as the polarity of your body is same that of the current (which happens in a fraction of seconds)....it throws you away (like charges repel each other).... although the shock will be more in case of DC but you may survive as the shock is momentarily..... But in AC you will be stuck with the wire as long as current flows​
In case of AC when polarity becomes same for a fraction of second it doesn't throws us away?
Polarity of our body changes.. how come?
@[Prototype] • 03 Aug, 2012
singh manvendra
AC is more dangerous than DC.... Since our body fluids are ionic in nature, when you touch a wire carrying AC current, the polarity of your body in contact with the wire becomes same as that of wire. But then suddenly AC reverses the polarity...Unlike charges attract each other and this phenomenon repeats. So you will remain stuck with the wire.

However DC does not change the polarity so as soon as the polarity of your body is same that of the current (which happens in a fraction of seconds)....it throws you away (like charges repel each other).... although the shock will be more in case of DC but you may survive as the shock is momentarily..... But in AC you will be stuck with the wire as long as current flows
DC will never throw you away because there is no reason to do that. Once you're stuck with the DC, it'll constantly flow through your body, however, the AC goes to a point where its value is 0 in every cycle. Following the repulsion theory you've presented, the AC should be the one who should repel you due to body unable to change the polarity at the same frequency as that of the wire.
@Ramani Aswath • 03 Aug, 2012 Physiology is different from physics.DC causes a single contraction of the muscle which pulls away.This does not happen with AC and you do not pull off. Disorientation of the shock prevents a conscious pulling back and you end up with a more harmful contact.
@Kaustubh Katdare • 03 Aug, 2012 Well, my point is that this is certainly not the AC current 'attracting' the person, like magnet attracts iron.
@Harish Sarma • 09 Aug, 2012
singh manvendra
AC is more dangerous than DC.... Since our body fluids are ionic in nature, when you touch a wire carrying AC current, the polarity of your body in contact with the wire becomes same as that of wire. But then suddenly AC reverses the polarity...Unlike charges attract each other and this phenomenon repeats. So you will remain stuck with the wire.

However DC does not change the polarity so as soon as the polarity of your body is same that of the current (which happens in a fraction of seconds)....it throws you away (like charges repel each other).... although the shock will be more in case of DC but you may survive as the shock is momentarily..... But in AC you will be stuck with the wire as long as current flows
Generally AC will throw a person and in case of DC the person will get stuck to it as the voltage remains constant and doesn't get a chance to save himself
@Ramani Aswath • 09 Aug, 2012 • 1 like
harishksharma
Generally AC will throw a person and in case of DC the person will get stuck to it as the voltage remains constant and doesn't get a chance to save himself
Not quite. What happens with DC is that the current causes a single muscle contraction, which pulls away the limb from the current. In the case of AC there is no single defined contraction. So the limb remains in contact prolonging the shock.
@Gurdeep Mundi • 01 Mar, 2016 what is this everyone have different opinion why dont you try touching a wire carrying ac and dc current then we will be able to get an exact answer
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