The Electricity: Don't Hold Your Breath

in #stemng6 years ago (edited)

I grew up around people who believe in a lot of myths. I was the in-house "engineer" of the family even as a child, I was forever fascinated with how things work, especially electricity. There is one uncle who was an electrical technician, we usually require his services every now and then. A question by @misterufem recalls one myth I was made to believe as a child which almost led to a disastrous outcome. The myth is if you hold your breath and touch a live wire that you will not feel any electric shock.



Image credits:Pixabay Link]

The local technician did not just say that that is possible, he apparently held his breathe and touched a live wire and did not flinch. I watched him do this, but as he never said what we hear when people perform a dangerous stunt on TV these days- do not try this at home- I did try that while he was gone with almost a fatal result! The story of what happened will make an entire post, moving forward, it was later that I got to know how he did it.

First, it has nothing to do with holding his breath, it has everything to do with electricity and how it operates.

For electricity to flow, electrons must move. The electrons travel through the wire/conductor to get to the next point of reference. Imagine climbing uphill with a bag of bowling balls, on getting to the peak of the hill, you throw down these balls. If the balls represent current, and there is a path made on the hill, it will move down the hill until it gets to the valley where all movement will cease. At the valley, the ball can no longer move because there is no difference in potential. This same potential is the main reason a bird can perch on a high voltage line and not get zapped or electrocuted. It stands on a single wire and this is on the same potential, the current will not have any potential difference for it to travel through the body of the bird.



Image credits: Pxhere Link]
But an overconfident/ careless bird may get itself fried if on taking off its wing mistakenly makes contact with another wire, there will exist a potential difference between these two points which will be analogous to creating another downhill path for the bowling balls on the valley to roll down in.

Back to my story, the electrician did a risky thing, but he may be acting out of years of experience. I later noticed he wore a heavy insulated safety boot and he was not making contact with any other object. Now, for electricity to flow, the circuit must be closed, eg when you turn off the lamp in your room, you merely opened up the circuit that breaks the electrical connection. Due to this added resistance, he had from the safety shoes, the circuit was not complete for electricity to flow through him to the ground. There is another factor why he was not electrocuted- his skin resistance and condition. The average body's resistance ranges from between 1000 ohms to 100,000 ohms if the skin is in dry condition. The body's internal resistance is as low as 300 ohms. The skin resistance of different individuals vary.

A person's total resistance in the event of electric shock is calculated as

Rtotal = Rskin(in) + Rinternal + Rskin(out)

Where Rinternal is the resistance of the inside of the body

Rskin(in)= resistance of the part of the body exposed to the live wire.

Rskin(out) = the current that goes in must exit for there to be a complete circuit and hence electrocution.

The electricity has to pass through the victim twice, one as it goes in, and the second time during exit.

Out of all the part of the human body, the hand has the highest resistance, with the mouth the lowest. You easily feel more pain in the mouth than the hand if electricity is made to pass through both places.

Also, a more calloused hand have a higher resistance as a result of the hardened skin layer. So, armed with a good electrical-resisting work boot, plus a somewhat dry calloused hand of a workman, he was able to pull off the stunt of holding his breath and touching the low voltage wire.

I would love to see him perform the same breath-withholding trick bare feet while standing on a wet floor with a sweaty palm! :) Of course, he won't be able to withstand the severe electrical shock due to the reduced resistivity of the body while wet and being unprotected by lack of insulating footwear.

There is a different "trick" or technique, I often find experienced electrician make use of; I call it the hand-in-the-pocket rule. The rule is simple, electricians place one hand in their pocket while working on live circuits.

First, one hand on a circuit reduces the contact area for electricity to pass in the event of an electric shock. With two hands in contact, the surface increases with a decrease in resistance, thereby increasing the amount of current that will flow in if the body makes contact with an energized circuit.

A 1.5-inch metal pipe, when held in one hand, has a resistance of between 1000 to 3000 ohms present at the dry condition. The same resistance reduces to between 500 to 1500 ohms when the hand is wet.



Image credits: By Omegatron CC BY-SA 3.0 Wikipedia, Link]

If the same metal is held with two hands, the resistance will half, i.e. will be about 500 to 1500 ohms with a dry hand and 250 to 750 under wet condition. The two hands will act as resistance in parallel:

Rparallel = (R1R2)/(R1+R2)

That is, the total resistance will reduce leading to more current to flow through.

Apart from this obvious fact, there is the critical detail of the path the electricity will flow. With the one-handed approach, it is always preferable that the right hand is put to work with the left in the pocket, a condition that favours the right-handed. The reason is that the heart, which is situated on the left side of the body is free from the path the current will take. It could be fatal if the path the current takes is via the heart area. So the fatality and severity are reduced by this approach, but normal electrical safety rules require that we do not work on live equipment or device, but in most circumstances, the circumstances may not allow for total shut down of the whole appliance.

Do you know of any other cool electrical myth? Please do share in the comment section and thank you for stopping by.

References



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Good grief - what a reckless stunt for that electrician to pull. Didn't he understand that kids always mimic the behavior of their elders?

I guess it never occurred to him that I'd try it.

I used to believe that wearing a rubber slippers would increase your resistance against electricity when you touch a naked wire (This is not absolutely wrong) I thought it was a rubber and electricity thingy now I understand the mechanism behind it

Thanks for sharing @greenrun

It offers some level of protection from current passing through you.

Wow! Now I really really got this. This is a very well detailed post. Your reply to my comment in your previous post, I wasn't that convinced, but on this point you mentioned below hear, clears everything and I'm so excited to know the secret behind.

I later noticed he wore a heavy insulated safety boot and he was not making contact with any other object. Now, for electricity to flow, the circuit must be closed, eg when you turn off the lamp in your room, you merely opened up the circuit that breaks the electrical connection. Due to this added resistance, he had from the safety shoes, the circuit was not complete for electricity to flow through him to the ground.

Thanks for sharing this. This is the reason why @steemstem as come to stay. Not only for the reward but also for the knowledge gained. The myth have been hearing for so many years, the secret is revealed today. Thanks to @greenrun

Thank you for your contribution and question. It made me dig deeper for more.

You're welcome sir! You must be a real scientist because

dig deeper for more

you said is not only enough but the understanding of what you've digged. And you've made us understand the whole theorem.

Thank you :)

Electricity could be as dangerous as it is useful. Most technicians that are not trained in the intricacies you have described would treat a lot of dangerous aspects of electricity with laxity and most times get away with it. Unfortunately, most onlookers would try it and not be so lucky.

This was an easy read. Well done!

Yes, those types set a dangerous example.

I've been tricked so many times by this holding your breath thing, as a matter of fact, i once tried it when i was in secondary, i'm sure you know what the outcome was, since then i rarely go near electricity, i like to tell people i have electrophobia...lol

At least now i understand why those technicians don't get electrocuted, it still doesnt ease my fear of electricity though, i won't be going close to an exposed electric wire anytime soon

Really? That's some scary experience.

I heard about the myth too...
Can't laugh when a Friend in the hostel back in School days tried it and got a real shock
I am well informed now...I love the calculations you did to support it

At least it wasn't a fatal outcome for your friend.

Nah...It wasn't
He sounded too confident when dealing with the wires
Luckily he it wasn't fatal

That's awesome :)

@greenrun sir

Thanks for this great post. I have been able to learn some safety tips as well as scientific explanations regarding some unfounded myths about electricity. It's such an eye opener to me.

Thanks

@sciencetech
STEM contributor

Thank you too :)


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I know many men who are frightened of electricity or electrical circuits. I have been told more than once that "I don't fool with electricity. I'm not ready to die." I'll ask them, did you cut off the power and test the circuit that you need to work on? If you take the necessary precautions, then regular household electrical work is safe and not very difficult. Thanks for sharing an in depth knowledge of the physics behind the myth.

That's very true, you have to obey the rules.

This is a very nice write-up. I was also nurturing the same myth. Thanks for making it clear to me, though I never did try touch a live wire by seizing my breath. I'm also kinda electrophobic. lol.

Never knew the myth is that widespread. Thank you for letting me know.