Which is more danger, AC or DC?

You guys should read about Tesla first. Edison was promoting DC and made sure the electric chair was AC to scare people away from AC. He would electrocute animals on stage to demonstrate the danger of AC. "Tesla, a man out of time" is a must read for anyone working with electricity.

Pasted from a website about Tesla:
"Arriving in New York City with four cents in his pocket, Tesla found employment with Thomas Edison in New Jersey. Differences in style between the two men soon led to their separation. In 1885, George Westinghouse, founder of the Westinghouse Electric Company, bought patent rights to Tesla's system of alternating-current. The advantages of alternating-current over Edison's system of direct-current became apparent when Westinghouse successfully used Tesla's system to light the World Columbian Exposition at Chicago in 1893."

Westinghouse was also a prolific inventor, to this day most railways still use the Westinghouse brake system.

Roy
 
Reading this I'm reminded of another danger: A hundered years after the Westinghouse company was founded it was run into the ground by top management handing the control to finacial managers who never learned what it was they were in business for. It was lost in half a decade...

Hugo
 
The most dangerous is known as the COLUMB EFFECT. This is when the power passes between the two hands, across the chest and thru the heart. This is the real killer.
 
The cyclical rate that A/C operates at will not allow a "lax time" enough for you to let go. a 110 V household circuit will kill you deader than a doornail. A 220V will do it twice as fast.
 
You need to ask the question, "To current, are people more resistive or reactive?" The question will lead you to your answer.
 
R
"To current, are people more resistive or
reactive?"

Definitely more reactive. I remember as an apprentice giving one of the journeymen a shock with the 500 V megger. He "Reacted" by giving me a belt over the ear.

Roy
 
R

raphael orimogunje

>AC or DC?
DC is more powerful than AC current supply, because DC frequency is direct current of 50Hz,which moves in a direct straight line. While AC current moves alternatingly from zero to 220v. a life could still be rescued in such cases. This makes the DC more dangerous.
 
You've got that backwards mate, Edison was for DC and had the whole of New York wired up in DC. Of course it was a disaster because of the energy lost in resistance that could be avoided the most part by using transformers in AC, which are not available for DC as DC does not have a changing magnetic flux.
 
DC stand for direct current. DC dos not alternate and therefore will always have a frequency of 0 hertz (cycles per second), unless you are pulsing it for radio transmissions or something but that is beside the point.
 
A
As DC is steady current its voltage remains same i.e 220v. The AC is RMS. it increases from zero to maximum value. for example I = 220v so I=I under root 2 so I = 220 multiply 1.414 so I = 311.08v.

Therefore AC is more dangerous then DC
 
>Both are dangerous if they were high
>voltages, for example more than 12V.

usually we used to say that the safe voltage is everything less than 50VDC or AC. this is why all equipment in 24 or 48 Vac/dc can be used in humid atmosphere or harsh environmental.

For example there is some actual talk and study to increase the battery voltage in cars as the electrical power used in vehicle is increasing drastically with all "automatic" equipment up to 5kw of electrical power in luxury vehicle is not rare. so to reduce Wiring size and weight manufacturers are thinking about increasing batteries voltage (and the whole electrical system of course) to 42Vdc!!! (less than 50Vdc)

Also, it is known that we need "high" voltage to "crack" the human skin and we need some current to maintain this crack. exactly the same as for electrical welding, High voltage to start the Arc, then a lot of current to maintain it.

But everything depending on the conditions, humidity, sensitivity of people, condition of electrification, etc
 
>AC is more dangerous since it deals
>with the amps. I've seen someone get hit
>by a 1000 Volts in a presentation. But
>only with 1mA a person can get killed.

you do not know what you are talking about....
AC deals with amps??? DC also deals with amps.
 
I
>Can any one tell me which is more
>danger: AC or DC?

defiantly DC o yes because DC is a direct current and will kill you if you have contact with it AC is safer because it is an alternating current so be careful if you are working with DC current
 
>Can any one tell me which is more danger: AC or DC?

The absolutely most dangerous voltage is the one you are working on.
 
C
This has been argued about, but it is widely held that AC is more likely to stop your heart or push it into fibrillation. There is a difference in your ability to let go also, but I don't remember which way it goes. I try to avoid testing these theories.

Regards
cww
 
P

Process Value

Danger factor : It is an accepted fact that for a given medium voltage DC is more dangerous.

AC has a definite frequency, thus skin effect kicks in and the current travels through the outer skin thus it does not damage your internal organs. Higher the frequency more pronounced the skin effect and greater the impedance it offers to the voltage. Ultimately what matters is the current flow which depends on the voltage. In ac because of the skin effect the impedance is more and thus lesser current flows, but in DC there is no skin effect and thus the current flows uni formally through the whole body smoking everything in its path. another advantage in ac (if you can call that) is that the current flow will cause a opposite force thus throwing you off.

but it all depends on the voltage level, it really does not matter if you go and touch a 400KV DC or AC (50/60Hz) line end result will be more or less the same.

so at a medium voltage level, say 110 V, 240 V, DC is more dangerous than AC.
 
Z

Zacharia, Tomy

I simply loved the part about not personally testing the theory.

Sometimes, people 'better' qualified to 'test' the same should be allowed the 'opportunity'.

Regards,
Tomy Zacharia
 
B
That is an interesting but completely wrong description of skin effect. There is very little skin effect at 50 or 60 Hz, and in any case, it has nothing to do with human skin.

It is true that there is a somewhat greater chance, at least theoretically, that one will be more likely to grip and hold on to a DC source over an AC one, but in practice, I suspect it really does not matter all that much.
 
J

James Ingraham

Process Value said, "It is an accepted fact that for a given medium voltage DC is more dangerous."

I disagree. I think it is a widely held belief with absolutely no hard data to back it up.

-James Ingraham
Sage Automation, Inc.
 
Top