Misconception #6: Low Voltage Shocks Are Not Dangerous

So today's post is regarding a wide-spread misconception, that is practically quite .. DANGEROUS.

In fact, many people, myself included, are generally under the notion that low voltage, like one found in batteries, is quite safe to deal with.

Heck I cannot count the times we had played with batteries as young kids. Parents scold their kids to stay away from electric outlets, yet not so when it comes to batteries.

Well, the truth of the matter is that:

Low Voltage Shocks Can Be Quite Dangerous!

So now that you've been warned, let us dig into the explanation.

How Come?

The main reason behind the risk is not merely the voltage, yet it is the current of electricity (measured in amperes/Amps or milliamps/mAmps). So even a battery with as low as 12V, while normally not fatal, can still cause some serious damage.
So to make it simpler, it is the amount of amps that can lead to muscle contraction, burned tissues, and heart fibrillation.
Of course, the higher the voltage, the higher the risk, and this is all governed by Ohms Law:

So there are several factors to the equation. Voltage, current, and body resistance. Higher amps, higher voltage. Higher resistance, lower amps.
And resistance differs from person to another, and from condition to another.

How much body fat does the person have? how hydrated is he/she?
Is the person a male or a female
How is the contact with the electrical appliance? direct with the skin (hand to hand, hand to foot,...)?
Is there sweat or blood on skin (which worsen the resistance)? or on the medium of contact?

Chart below illustrates some of the mAmps effects on different persons

You can also see some of the resistance values in Ohms in the chart below

If you combine those two charts together, you can notice that a voltage as low as 20V, in the right conditions, can lead to serious health risk.

There was even a recorded case where one sailor was able, through conducting an experiment, to electrocute himself to death using a 9V battery, as explained on the original reference:

When we did the experiment in the electrical safety class to determine our body's resistance, we found a resistance of 500K Ohms. Using 9V and 500K Ohms in the equation, we come up with a current of 18 microAmps, below the "feel" threshold of 1mA. However, removing the insulation of skin from our curious sailor here, the resistance through the very good conducting electrolytes of the body is sharply lower. Around 100 ohms, in fact, resulting in a current of 90mA - sufficient to stop our sailor's heart and kill him.

So instead of using the "Danger: High voltage!" we might opt for a more accurate warning sign:

Danger: Voltage!

Hope you learned something new today .. and thank you for stopping by!
@mcfarhat

From this series:

If you enjoyed this post, you might want to check out my earlier posts from the "Misconceptions" series:

References:

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