As an Electrical Engineer you should aware of current whether its AC or DC.And it is responsibility also to aware other people and advice them to take proper precautions.
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Which is more dangerous ?
AC and DC both are dangerous. What really tends to kill you is current, so enough current whether AC or DC both can be deadly.
Due to zero current passing point some people says AC is less dangerous than DC. and some people assert that DC is less dangerous. So there is a misconception about this. Just go through this article and you concept will be clear.
There is some difference in shock between AC and DC. Although I haven't experienced DC shock that much amount. I had get shock form 15V DC when positive side and negative side both are touched my tongue. But I can explain you an account of utmost shock from AC current. It causes muscle spasms, fibrillation of the heart and an unconscious state which leads to freeze the victim or part(s) of the body touching the AC source.
In case of DC, it causes a single convulsive contraction which shove the victim from the DC source, he or she touched.
Because of alternating nature, AC can causes to hearts pacemaker neurons into atrial fibrillation, more dangerous than DC, where cardiac standstill (because of ventricular fibrillation) occurs in case of electrical shock. There is a chance for 'frozen heart' to get back on the normal track as compare to fibrillating heart caused by AC. In medical service defibrillation equipment is used as emergency purpose which supply DC units to halt the fibrillation and bring back the heart to normal condition.
The ultimate decision depends on so many factors like wet or dry skin or place, age, human body resistance, voltage, frequency etc.
Ac is more dangerous than DC. And low frequency (50Hz or 60Hz) AC voltage or current is more dangerous than same level of DC voltage or current. That means 230V Ac is more dangerous than 230V DC. But keep in mind , DC has also ability to roast you.
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Why AC is more dangerous ?
Low frequency (i.e. 50Hz or 60Hz) AC is more dangerous than high frequency AC. AC Power is four to five times dangerous than DC having same level of voltage. There's a couple of reason for this.
The first is that when someone mentions an AC voltage that means mentioning the effective value or RMS value. So the peak value of AC is higher RMS value as Peak value = √2 ｘRMS value.
As we know for AC -
V = Vₚ sinωt
∴ V = √2 Vrms sinωt
∴ V = 1.414 Vrms sinωt
if Vrms = 230V ⇒ V = 325 sinωt
from above calculation we can see that for our domestic supply which is 230V or 120V(in US) AC are RMS value and the peak values are 325V or 170V. whereas DC has only RMS value that means only 230V or 120V DC.
In other words, AC turns out more about 325V or 170V that means it more than that it appears. So from here you can understand that AC is more dangerous.
Secondly, human body can resist DC better than AC. Human body has capacitance in it on top of just resistance. That means human body acts like an insulating medium between the live wire and the ground. and we know the capacitor blocks DC and pass AC through it.
DC has zero frequency. So fdc = 0
and suppose for AC frequency, fac = 50Hz or 60Hz
Resistance in DC : Xc = 1/2πfC
As, fdc = 0 ⇒ Xc = ∞(infinite)
That's why capacitor doesn't allow DC to pass through it.
Impedance in AC : Z = R + jXc
∴ Z = √(R² + X²c) and Xc = 1/2πfC
and I = V/Z
if frequency = 50Hz or 60Hz , Z(impedance) will decrease. Then current will flow easily. So, AC has ability to pass easily through the capacitor. That's why AC is more dangerous than DC when human body acts as a capacitor.
The third is that frequency. Some people has concept that AC is less dangerous than DC because of alternating nature of AC. Here alternating nature means AC changes its direction multiple times and it touches zero value 50 or 60 times per second due to frequency and there is chance for victim to skip the shock where as DC has no frequency.
if frequency is 50Hz or 60Hz (US), then lets check how fast AC changes its direction -
DC has zero frequency. So fdc = 0
and suppose for AC frequency, fac = 50Hz or 60Hz
Resistance in DC : Xc = 1/2πfC
As, fdc = 0 ⇒ Xc = ∞(infinite)
That's why capacitor doesn't allow DC to pass through it.
Impedance in AC : Z = R + jXc
∴ Z = √(R² + X²c) and Xc = 1/2πfC
and I = V/Z
if frequency = 50Hz or 60Hz , Z(impedance) will decrease. Then current will flow easily. So, AC has ability to pass easily through the capacitor. That's why AC is more dangerous than DC when human body acts as a capacitor.
The third is that frequency. Some people has concept that AC is less dangerous than DC because of alternating nature of AC. Here alternating nature means AC changes its direction multiple times and it touches zero value 50 or 60 times per second due to frequency and there is chance for victim to skip the shock where as DC has no frequency.
if frequency is 50Hz or 60Hz (US), then lets check how fast AC changes its direction -
T = 1/50=0.02sec
or T = 1/60 = 0.017sec
So, during 0.02sec or 0.017sec AC touches the zero point twice but human brain is not that much faster (except the unintentional functions) to response electric shock and move back from the voltage source.
📝Note :- Remember always that current kills, not the voltage. But Voltage is cause to drive current. Both AC and DC are dangerous. My advice to everyone who is working with electrical equipment , please take care of safety. Do not touch the live wire, you cannot get back your life if you loose it, then no matter which one is less dangerous or which one is more. If anyone get electric shock, try to disconnect the power supply and push back the victim from the source (Before push back, you should proper insulated, keep in mind).
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