Why DC System Is More Dangerous Than AC System?

Which one is more dangerous either DC or AC power, especially when it shocks a human body. Other way we can say, if we can take the same amount of AC and DC current onto our body which one would hurt us more?

The answer- DC (Direct Current) is more dangerous than AC (Alternating Current), but why DC is more dangerous than AC?.

Before we find the answer for dangerousness of DC or AC, let we know the basic definition of DC and AC:

What is DC System?

What Is AC System?

DC or Direct Current could be defined as the one direction or unidirectional flow of current. Current does not change its flowing direction, only flows in one direction. The amplitude of voltage and current may vary over the time but flow of direction always unchanged.
Plot of Direct Current Waveform
AC or Alternating Current could be define as opposite the DC, changes direction periodically. Not only changes, periodically reverse direction. The amplitude of voltage and current vary and reverse over the periodic.

Plot of Alternating Current Waveform

Why DC Shock is More Dangerous than AC Shock?

It would be difficult to mentioned DC is more dangerous than AC for electric shock. But, if we consider the same amount of DC an AC current flowing through a human body for a certain period of time from a same voltage difference, then could say the DC is more dangerous than AC or not.

If you look at the both waveform (red mark lines in above figures) for DC and AC: for DC the amplitude or amount of current is same in respect to time variation.
On the other hand, for AC the amplitude or amount of current is varying, it is increasing from zero to positively and after maximum it is again decreasing up to zero and up to negative maximum and again coming positive maximum through zero.

Now, comparing the DC and AC waveform there is a zero amplitude in AC system that is not presence in DC system. This zero amplitude is known as "zero voltage crossover point" in AC system.

This zero amplitude for a period in AC system is giving a chance to release  from the touching live conductor. This is the secret of AC is less dangerous than DC for electric shocking.

Does Really DC is Safer Than AC Voltage?

It is still debatable and there is no conclusive research on safety of one over other because this cannot ethically tested on humans. People who would say that AC is more dangerous because it's pulsating nature disturbs the nervous system;

On the other hand, some would say that AC is safer because it gives time for nervous system to react during Zero-voltage crossover points in AC.

Actually both AC and DC current and voltage are dangerous. People who speak of AC is less dangerous than DC are, but statistics of electricity shocking accident says most of the peoples are dying in AC system though there is zero current passing point which lets you to go or leave your muscle to relax.
Keep electricity safe rising the safety awareness, as far as safe voltage levels are concerned some UL standards consider 42 V AC/DC to be safe and some ECMA standards even consider up to 60V DC to be safe.


  1. Advantage of AC:
    cheaper to generate, transmit and distribute.
    Easy step-up/down
    Robust motors like induction motor run on A/C

    Disadvantage of AC:
    AC is not very efficient to transmit over long distance compare to HVDC
    Most of electronics gadgets do not run directly on AC.
    Needs power factor correction to maintain efficiency of the distribution.


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