Monday, September 6, 2010

Bad Idea - Sticking a Knife in a Socket

Have you ever wondered what would happen in you stuck a knife into a socket?  Come on, don't be like that, I know you have thought about it, and really, who hasn't.  Everyone always wants to do what they are told that they can't, and I am pretty sure everyone has been told not to put anything onto a wall outlet.  But the real question is "why shouldn't I? I mean, what is the worst that can happen?"  So starts a new segment I like to call "Bad Ideas."

                                         Tom Bloom (c)


So why is it a bad idea to put a knife, or wet fingers or anything conductive into a wall socket, and what would happen if you did? Well, as we all know, there is electricity flowing through the wires in the wall, and when you plug something into the wall, to completes the connection or circuit and allows the electricity to power the appliance that is plugged in.  The wires themselves, are essentially harmless until the circuit is complete.  Electricity always wants to be grounded, and the human body is a good conductor of electricity due to us being mostly water sacks. That is why a bird can sit on a wire;  there isn't enough voltage drop across their bodies and they are not connected to a ground source.

So if you stuck an un-insulated knife into a wall socket, you will complete the circuit, and essentially the electricity will flow through you and ground itself.  Depending on where you are in the world will dictate how much is going to flow through you.  If you are in North America, you will get 110V, 60Hz, whereas, in Europe, you will get 220V and 60Hz.  You would feel a pulse going trough you at the same frequency of the electricity, around 60 pulses per second (which is a Hertz), and there could be serious injuries or even death.  So long story short, it is a bad idea.  For more information, check out howstuffworks

Incidentally, it is possible, though not recommended, to stick a metal object into a socket and not get electrocuted so long as the handle of the object is well insulated.  The insulation acts as a barrier to prevent electrical shock.  That is why you can handle appliances that are plugged into the wall and not feel the wrath of the electrical current.

-d

5 comments:

  1. But how do you complete the circuit by sticking a knife only into 1 terminal? Wouldn't the worst be you just get a shock as you a create a potential difference of your body at low potential getting raised to the higher potential of the wall socket, but no actual current should flow through the body as there is no return path, right?

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    1. The building floor contains water. Even a piece of plastic absorbs some amount of water. Water is an insulator, if it weren't for the impurities. Impurities there are a lot. So the circuit will be closed with the floor. To counter that, electricians working on live circuits are required to stand on isolating mats. Another way to protect yourself _and_ touch a live wire is by using an insulation transformer. This essentially breaks the earth as being the return pole of electricity. So to be electrocuted, you'd need to touch both poles (you'd find that in lab power supplies, galvanic isolation).

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  2. Back in highschool there was a single prong sticking out of a wall socket where the plug had broken off into the wall. It wasn't the ground prong either. But anyways me not thinking about it, and it bothered me I grabbed it to pull it out. I felt the shock go into my hand and up my arm before I let go realizing what happened. But the shock to me felt nowhere near dangerous or deadly. Is there any possible explanation to this? All i can come up with is the boots I was wearing that day. I had a pair of work boots on that were very thick in rubber on the bottom.

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  3. For health and safety reasons some schools are required to have a transformer which reduces the current a bit more. This makes it less lethal- but still mildly dangerous just cos it’s electricity.

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