Wednesday, June 2, 2010

Which one is more dangerous, AC or DC?

This question has been asked by many people who have experienced an 
electric shock before.I recently received an electric shock from the 
domestic household current of 10A.The feeling was ecstatic. Many will come 
across large AC currents, but have you ever thought of DC Electrification? 
This would sound weird because DC current available in domestic premises 
is in the order of mA (milliamperes). In industrial environments  DC current 
is available in large quantities and is very lethal when handled improperly. 
The severity of a shock largely depends on:
---Amount of current 
---Amount of time on the exposure 
---Resistance of the body.
AC:Alternating Current
AC in theory would allow your muscles time to be able to move so that you could pull your hand / limb 
away from whatever it was that was giving you the shock. This is so because AC alternates from zero 
to maximum (amplitude) in a specified time frame (frequency).It is during this timeframe that muscle 
signals may retract you hand/limb...
The time frame we are talking about here is only a few milliseconds-which means that for larger 
currents, there is no time for reflex action. However as I said above,
 this largely depends on the amount of current flowing. 
Starting current of motors (128A) would never give you a chance of even thinking!
AC current will allow you to move your hand for the muscles which are not in the path of the electric
 current.In AC (Alternate Current) the muscles will contract and extend and through the spasms you 
might eventually free yourself (that is why people say that the current threw them while, in fact, 
it was their own muscles).

DC: Direct Current Definitely DC. The passing of current through the muscles make them contract. 
In DC (Direct Current=0Hz) it will make your hand clamp the live wire; that is why, when in doubt, 
you should touch wires with the back of the hand. In AC (Alternate Current) the muscles will contract 
and extend and through the spasms you might eventually free yourself (that is why people say that the 
current threw them while, in fact, it was their own muscles). No time for conscious efforts when under 
current. Do not be fooled, NO ONE can sense the zero voltage "in between" the 50Hz (cycles per second!!!). 
People tend to underestimate DC because in normal life one encounters very low dc voltages while the 
mains ac is everywhere. Given the proper voltage DC will kill you. By the way, it is not as much the voltage 
as it is the current. A potentially lethal (depending on the health condition) value starts from a 20mA current 
through your body. The better the contact (e.g. wet hands, bare feet) the lower the lethal voltage. 
You better stay away of voltages over 24V (AC or DC) if you have no special qualification. ---Electrical Engineer

If DC was used at 240v in household appliances then somebody would die every day. AC is very safe then DC 
 at high voltages because it alters its charges. DC can be safely and easily stored in low voltage in batteries 
and that's why people have these wrong assumptions that DC is safe.

After the above arguments I have come to a conclusion that DC Current is far more lethal than AC because:
DC  will not release you at the point of contact with live conductor
DC will cause fibrillations in the heart leading it to stop due to over-contracted muscles.This is caused by 
AC also but DC is more severe.DC causes a clench in hand muscles that’s why when not sure, use the back of your hand. 
The clenching causes the victim to grip the conductor and won’t let go.
Safety First
Whichever the type of current in question, NEVER attempt to come close or even think of touching. 
Follow all electrical safety tips when handling AC and DC. Both of the can kill with ease when mishandled.


  1. Angela Wambui KiharaJuly 15, 2010

    Now do a story on solar power.

  2. Thats on the way.Actually I was working on it but got distraced be this wonderful World Cup.

  3. Year by year thousands of people are injured or killed from electrical shocks/contacts. They are exposed to dangers such as electric shock, electrocution, burns, fires, and explosions. The proper grounding of electrode system, conductors, equipment, and equipment conductors can help us in reducing the number of casualties. In order to understand grounding and bonding effectively, Contractor Continuing Education will certainly help you in understanding the best way of grounding and bonding per the National Electrical Code (NEC) 2008 standards.