AC vs DC Power: Which Is More Dangerous to the Human Body and Why?

Is AC power or DC power dangerous for human body?

Neither in small amounts, both in larger amounts. Grab a 12v car battery, or 12vac transformer. You might feel a slight tickle. Up the voltage, and you'll feel more than a tickle. Allow some amperage to flow, and you could be in trouble, depending on whether you use two fingers on one hand, or one finger from each hand (across the heart). AC has a tendency to release your grip as it crosses zero volts, dc tends to make your muscles grab and not release.

Few milliAmp is sufficient to stop the heart's actvity permanently, AC or DC , if body is moist then few milli amp. will be fatal AC or DC, but in general same value of DC is more degerous than same value of AC.

h1. b
Bill sparks as a electrician for 60 plus years i can inform you that A.C. & D.C. is fatal at the right voltage & current,
above 10 mil amps & ABOUT 80 VOLTS . IS FATAL IN MOST CASES . I have first time experience of this
I have been saved twice during this 60 yrs both on A.C. at 240 Volts, normally if you are griping hard on cable &
tools, then in most cases you can not let go, even during the voltage going to zero for the 50.th of a second.
the first time this happen to me was when i was 16, the Electrician grab my coat and pulled me off saving my
Life.
it is a bad feeling and you feel very shaken for about 10 mins. the second time was when i was reaching up
to strip the cable coming out of the ceiling (the cable was lead covered ) my hand slipped up on to the lead
covering also my other hand moved up the stripping tool to come in contact with the metal of the tool i was hol
ing getting a electroshock my legs gave way forcing me to fall to the floor, releasing me from the cable .
SO ALWAYS SWITCH OFF THE MAIN SWITCH . (IT IS ALWAYS UNEXPECTED ) ALL THE BEST, ALWAYS
WORK SAFELY. I AM NOW 74 AND HAVE HAD LOTS & LOTS OF SMALL SHOCK S DURING MY WORK, ITS
HAD NO BAD EFFECT THAT I KNOW OF.

The minimum voltage that will shock you depends on how well you are connected. If your skin is wet the voltage needed to shock you drops significantly. Basically the voltage needs to break through your skin so a path can be established through your bloodstream.

I'm not sure that there is a significant difference between AC and DC. Your muscles don't react fast enough to release you from AC. 60 Hz is on in different polarities every 8 ms. so the time that the voltage is minimal is way less than a ms., especially after current has been established. If you try and tap a button quickly it is about impossible to push it for less than 100 ms so 1 ms or even 8ms off time might as well be continuous.

I have worked on control systems around AC from 120VAC to 12KVAC or so. (I worked with two electricians who dropped a crescent wrench on the buss bars of a 12KV MCC. The wrench vaporized completely and they were both sun burnt and blinded for a few days from the flash.) I am really, really careful around any voltage over 24 VDC so I have no direct experience but I know people who have.

It is generally accepted, and the experience of some electricians that I know, that voltages of 480VAC or more produce such severe contractions that if you make contact with the palm of your hand you will be unable to let go and if you make other contact you can be thrown quite a distance, causing other injuries. For this reason some electricians that I have known with personal experience that, even after they've taken ALL precautions, initially brush possibe hazards with the back of their hand, rather than their palm.

P.S. Even if you live through the shock, the possible effects of high voltages include broken bones from muscle spasms and the cooking of your internal organs. I also knew a man who took a really big hit, after taking all the established precautions, and spent 5 months in intensive care with severe internal organ damage. He never really recovered.

Both are dangerous with a large amount of current and can be fatal.

Both are dangerous depending on the voltage. But still AC has a higher chance of killing than DC since it requires less milliamps to be lethal.

Anecdotally, I've heard electricians say that 440 VAC is the most dangerous. It's because if you contact it with your palm you can't let go, while voltages like 1200 VAC and higher throw you across the room. Some Electricians make a final test, after lock out, by brushing the circuit with the back of their hand so they can't grab it.