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Generally speaking at same voltage level and same current which, current is more dangerous AC or DC or are they the same?

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AC voltage adds some advantage technically as in every cycle it is going from positive to negative with zero in between. If you are considering levels which are dangerous for human being. I think it depends on what part of your body is in contact with conductor and whether you are touching ground(earth) or not.

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From a purely electrocution point of view they are both the same since they will result in the same current flowing thru your body.

I've heard some claims that if your hand is clenched around a conductor electrocuting you, that you have a better chance of being able to let go with AC as apposed to DC.

In the end, both are dangerous at the same voltage. Whether you actually get killed or hurt at any particular voltage depends on parameters of the situation, like how moist your skin is where the contacts are, the contact area, and where in your body the current flows. These factors are much more variable than any small advantage AC might have in being able to let go. And note that the letting go part only matters if contact is such that the current is clenching muscles that then cause better contact.

Consider them both dangerous according to the voltage. Don't get a false sense of security by thinking one is a little less dangerous than the other.

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    \$\begingroup\$ I would imagine the alternating nature of AC to be more likely to cause ventricular fibrillation, those cardiovascular control circuits are pretty sensitive. \$\endgroup\$ – Sam Jan 29 '17 at 20:45
  • \$\begingroup\$ But then, I often found with my power supply that if I touch a naked output terminal of the 220V-12V step down transformer, it feels like a shock. But if I touch the live wires after the bridge rectifier and capacitor filter (i.e. when it is converted to DC 12V) the shock is no more felt. From this I interpreted, the impact of 220V DC and 220V AC might be same in my body, but in reality the nominal voltage that human body can sense in normal conditions, is smaller for AC. I mean, we might start feeling shock with AC current at a much lesser volt than that of the DC. \$\endgroup\$ – sribasu Feb 3 '17 at 19:46
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Electrocution is not the only danger.

If you start an arc, e.g. in a faulty switch, an AC arc may be self-extinguishing (during the zero crossing) whereas a DC arc will not.

You'll often see switches or relays rated for a given current, say 10A, for 240V AC ... or only 30V DC.

Apart from the fact that such an arc leaves your circuit powered despite the switch being OFF, it also dissipates power, generating heat, and potentially starting fires.

So, there are some additional dangers from even moderate (48V downwards) DC voltages.

There are further dangers specific to low voltages, because (for the same power) they involve higher currents, and large batteries can supply thousands of amps.

Never carry a metal ladder in a battery room.

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One other thing to know is that AC can flow even when there is no apparent conduction path. Thats because ac current can flow through capacitances, and high frequency currents flow better through capacitances than low frequency currents. I know the question was probably intended for DC vs line frequency (commercially 50 or 60Hz), but this is definitely a concern with higher frequencies.

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well, this guy survived and it was AC:

enter image description here

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enter image description here

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