Is alternating current more dangerous than direct current?
And give me explanation for that... Assume that 230 V, 50 Hz AC voltage and 230 V DC voltage. Which is more hazardous to human life?
Which has more probability of risk?
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asked Jan 14, 2013 at 13:34
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7\$\begingroup\$ Aaah... Classic "Thomas Edison and George Westinghouse" war! Check out: pfeiffereng.com/Principals%20of%20Electrical%20Grounding.pdf \$\endgroup\$– SwanandJan 14, 2013 at 13:41
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2\$\begingroup\$ The answer would depend on whether you're looking for medium-rare, or well done. \$\endgroup\$– Anindo GhoshJan 14, 2013 at 14:22
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1\$\begingroup\$ The way this game works is, anyone who chooses one over the other gets downvoted. \$\endgroup\$– gbarryJan 14, 2013 at 15:52
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1\$\begingroup\$ Perhaps, while we're here, we could clear up that little matter of assembler vs C. :^ \$\endgroup\$– gbarryJan 14, 2013 at 15:55
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\$\begingroup\$ @Swanand best part: "Figure 1 also shows two stick figures, Safe Sally and Suzie Sizzle to illustrate how the human body can become electrocuted. The use of female names is only to provide names that are easy to remember and which rhyme with safe and sizzle and in no way intended to indicate that women are unsafe or more easily shocked." \$\endgroup\$– Phil FrostJan 14, 2013 at 17:49
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3 Answers
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AC has some time period - frequency. It repeats itself and periodically touches zero. However DC remains at a constant voltage level. Let me compare on different points:-
Due to such nature of AC, there is a "Let go" thing with AC, At a specific point it may let you go and you could be safe. However, in case of DC, there isn't any chance.
It also depends on factors like Skin Moisture. Moisture conducts!!
When you are shocked with AC, it generates ripple in your body of 50Hz (In this case) which contracts your muscle and you get heart-attack. When you are shocked with DC, it electroculates your body i.e It separates chemicals from your cells. (In both cases, You Die!)
For DC, Path Matters! If DC passes from say one finger to other, you might feel burns that's it... But AC spreads across body.
At High frequency, AC is comparatively safe... Yes.. Due to Skin effect, it flows from your skin! :) No such case for DC (0 Hz)
So both are dangerous under appropriate circumstances!
This is refered as "War of Currents" between Thomas Edison and George Westinghouse!
P.S. IN ANY CASE, DON'T PLAY WITH ANY.... BOTH ARE DANGEROUS!!
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This is like the question, "Which is more dangerous, a pit full of spikes, or a giant swinging blade?"
You can argue about the different ways in which they may kill you, but it doesn't much matter when you are dead, does it?
answered Jan 14, 2013 at 14:05
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5\$\begingroup\$ There is nothing wrong with being curious about electricity. Curiosity is not the same as stupidity. \$\endgroup\$– stanriJan 14, 2013 at 14:16
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1\$\begingroup\$ @stanri I didn't say it was a stupid question. I said it doesn't have an answer. The question was not, "how does AC kill you differently than DC?", it was, "which is more dangerous?" Fact is, they both kill. They are both dangerous. Your survival will depend on so many factors other than whether it's AC or DC it's not worth debating, unless you are trying to resist the adoption of AC power distribution for commercial reasons. \$\endgroup\$ Jan 14, 2013 at 14:22
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1\$\begingroup\$ "Which is more a hazard to human life" is a very good question because it explores the differences between AC and DC and in the real-world scenario that is mentioned, one is definitely more hazardous than the other. There is an answer. \$\endgroup\$– stanriJan 14, 2013 at 14:26
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\$\begingroup\$ @stanri: would you feel safe grabbing a wire with 230 VDC or 230 VAC? I wouldn't. I think I could quite likely be dead in either case. Would you rather be stabbed or shot? Would you rather be dragged under the ocean or shot into outer space? \$\endgroup\$ Jan 14, 2013 at 14:30
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\$\begingroup\$ As a kid, I grabbed an 220V AC bare wire by accident and I'm still here. I get what you're saying. you're concerned that now I'm saying that it's ok for everyone to go put fingers in their plugs. No, of course not, that's stupid. I'm just answering the question. \$\endgroup\$– stanriJan 14, 2013 at 14:34
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AC is more dangerous for a human being. The common 50Hz may causes the heart to go in fibrillation. Without a quick medical attention you'll die in minutes.
It is true that it is the current that will cause the damage, but in AC only 30mA is sufficient to put you in fibrillation if endured for several second. It is also sufficient to block your lung muscle. Given the body resistance, it only need ~50V AC to have that much of potential.
answered Jan 14, 2013 at 14:40
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\$\begingroup\$ "potential" refers to EMF, not current, as you seem to intend in your last sentence. \$\endgroup\$ Jan 14, 2013 at 14:53
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\$\begingroup\$ Umm... Where did blocking of lung muscles come into the context of cardiac fibrillation? \$\endgroup\$ Jan 14, 2013 at 15:48
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2\$\begingroup\$ 60Hz is too fast to cause fibrilation. The heart would low-pass filter this. Fibrilation frequencies top out around 300 bpm = 5 Hz. Basically to get fibrillation the heart cells have to be able to reset in between contractile pulses. At 60Hz they just stay contracted. It'll still kill you, but not from fibrillation. ;-) \$\endgroup\$ Jan 18, 2013 at 11:36
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1\$\begingroup\$ Unless something is really very wrong, the heart muscle will not tetanize. It has a fairly long refractory period. You can, of course, get circus rhythms -- fibrillations. Microshock through, say, a low impedance catheter, even at 60Hz, even just a few cycles, can of course cause fibrillation. Fibrillation does not equal tachycardia \$\endgroup\$ Jan 23, 2013 at 1:16
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\$\begingroup\$ Sustained 60Hz will not cause circus rhythm (another name for that is re-entrant tachycardia), but otherwise we are agreed. \$\endgroup\$ Jan 28, 2013 at 20:11