doubt on dangerous one in AC or DC

[arava prakash]

HELLO FRIENDS
I have read many threads and their replies, different answers are given by different fellows but which one I have to follow
FOR EXAMPLE
"WHICH ONE IS DANGEROUS? AC OR DC?????????"

So please reply to the thread
consider a condition where "50 hz AC" and "DC" having same amplitude.Now which one is DANGEROUS? AC or DC.


thank you

 

[betwixt]

BOTH !

It is the heating effect from the current flowing through the body and physical damage from muscle spasm that makes them dangerous. It makes no difference whether it is AC or DC if the current is high enough to cause injury.

If the person is still capable of movement, there is, under some circumstances, slightly more chance of them escaping from AC because muscle spasm tends to work in opposite directions as the polarity changes so combined with the mass of the body it has less effect on overall movement. DC wil tend to stretch muscle during spasm and hold it in place, making it more difficult to pull away.

However, for all practical purposes, they are equally dangerous.

Note it is the current that does the damage - not the voltage unless it is high enough to arc to the body in which case it can cause severe burns.

Brian.

 

[amayilsamy]

That's current flow what kills and if it's high enough it really doesn't matter if it's DC or AC. However, if one happen to survive the shock itself then DC is more dangerous. It's because DC current does elecrolysis of body fluids and products of it are toxic. So it may happen that few hours after shock one dies because of poisoning.

 

[tubelectric]

As far as I have understood (correct me if I'm wrong):

DC: Harder to get your hands off

Low frequency AC: Strongest effects on heart, fibrillation is more likely

High frequency AC: Causes mainly burns (and less pain, may even go unnoticed??)


But as a general rule - no electricity can be considered safe if the current through your body exceeds a few mA's!

 

[burrow]

I would say DC is more dangerous..Since AC signal is alternating it actually gives a break in stretching or contracting muscles But in the case of DC it is like a sudden damage, it doesn't actually give a gap.

So basically i would say ac is like chopping.it gives a small pause where you can take of your hands, but in the case of dc it actually Doesn't leave you with a gap

 

[betwixt]

As mentioned in post #2, DC can make it impossible to retract from the danger while AC may give you a chance.

With only 10mS between voltage peaks and considerably less than that when the voltage may be low enough to allow muscle action, I doubt it would give chance to "take off your hands", that gap is incredibly short.

Brian.

 

[BradtheRad]

But as a general rule - no electricity can be considered safe if the current through your body exceeds a few mA's!

I once read just 1mA can be lethal (by stopping the heart).

I once did measurements. I found I could not bear the sensation of 500 uA going through me.

 

[FvM]

As most Edaboards members will be aware of, this is a serial topic. I guess, all thinkabable questions have been answered several times.

I once read just 1mA can be lethal (by stopping the heart).

Refer to the commonly agreed safety limits I quoted in a previous same topic thread. https://www.edaboard.com/threads/93956/#post509830

 

[arava prakash]

the current that does the damage - not the voltage.

Brian.

many of the edaboard members are state like this
but up to my knowledge (correct me if i am wrong)
" current flows due to the voltage difference ",
so how the current only does the damage - not the voltage.

- - - Updated - - -

DC can make it impossible to retract from the danger while AC may give you a chance.

With only 10mS between voltage peaks and considerably less than that when the voltage may be low enough to allow muscle action, I doubt it would give chance to "take off your hands", that gap is incredibly short.

Brian.

As the force of attraction and reflection are equal in magnitude,
at low voltage peaks our muscle action is sufficient to take off our hands
but at high voltag peaks our muscle action is difficult and not possible

 

[betwixt]

It is true that to produce a current you need a voltage but the other factor is the resistance (Ohms Law). With dry hands which have a fairly high resistance you can probably withstand quite a high voltage because your resistance is high and the current is low. With wet hands, your resistance will be much lower so the same voltage will produce a much higher current.

It is the current that does the damage, how much voltage it takes depends on how conductive you are at the point of contact.

Note that even AC, which I stress MAY make it easier to disconnect yourself, will still cause damage if enough current flows.

Brian.