What Causes Damage In The Human Body During an Electric Shock: Current Or Voltage?

Friends, neither voltage nor current can damage our body in case of an electric shock, or rather it seems to be a paradox because they both are interrelated. You may know that it's a combination of voltage and amperage that presage an electric shock.

 Furthermore, it's explicitly possible that a high amount of voltage can zap your hands away and eliminate massive harm from electric shocks, but a small amount of voltage with a high current can kill you. Thus, it’s a combination of voltage and current (especially with higher value) that causes a deadly electric shock. 

What's the amount of voltage and current that causes damage? 

It's a steady-state voltage up to 42.4V peak or 60Vdc, which cannot be considered hazardous in dry conditions.  

{Ref. to IEC 60950-1:2005}

And, it's as little as 5 to 10mA current that can start causing muscular damage; current above 100 mA can cause muscle paralysis, breathing disruption, skin burns,  possible ventricular fibrillation, and death.

{Ref. to Electronic Troubleshooting by Mc Graw Hill Education}

Also, the possible extent of damage by a particular combination of voltage and amperage depends on the amount of resistance of the body. For example, the lower the mass, the lower the threshold (limit of energy), and vice-versa. Other body variables include age, state of health, effects of drugs, skin characteristics, and even outward appearances sometimes.   

{Ref. to IEC 62368-1:2018}

Effects of Electric Shock on Human Body

When current follows through a human body, the hearts and lungs are interrupted, causing temporary or permanent effects. That can cause imminent death. One common condition is called ventricular fibrillation, which causes a disruption of the heart’s natural muscle rhythm and makes the muscle contract rapidly and randomly. Typically, this condition is of victims who experience household deaths as a result of the person’s heart triggering fibrillation.  

Safety Considerations

Hence, for engineers and users, before getting in touch with any electrical and electronic device while using or troubleshooting, it's become critical to abide by some general safety considerations as follows: 

1. Carefully read the service manual and other supplements. 

2. Always ensure the correct polarity of any equipment. Needless to say, incorrect polarity can cause the device to explode. 

3. Always try to eliminate the use of a chemical or spray near the electronic device. 

4. Follow the service manual recommendations for cleaning electrical contacts by using only solutions suitable for the device. 

For example, 90 percent isopropyl alcohol is often recommended for electronic contacts acetone with an application using a pipe cleaner, a cotton swab or, a comparable nonabrasive applicator. However, caution needs to be taken since this material can be flammable.

5. Always use a suitable high-voltage test meter, such as a digital voltmeter (DVM) with a high-voltage probe attachment.

6. When servicing devices, use a proper ground lead from the chassis ground and remove the test receiver ground leads first when completed.

7. When soldering, use a grounded-tip low-wattage soldering iron. 

8. Always keep the soldering iron tip clean and well-tinned.

9.  Avoid overheating electronic components when soldering.

10. To avoid the risk of electric shock, we can also use an antistatic product on the floor, like mats or ground bracelets. 

This short write-up is supposed to answer “What Causes Damage in the Human Body: Current or Voltage?” and “How Can We Prevent Electric Shock?”.