Speaker 1: Welcome to brain Stuff from house stuff works dot com,
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Speaker 1: Brain with today's question. Why do the plugs on some
Speaker 1: appliances have two prongs and others have three prongs. Let's
Speaker 1: start with what the holes in an outlet do. When
Speaker 1: you look at a normal hundred twenty volt outlet in
Speaker 1: the United States, there are two vertical slots and then
Speaker 1: a round hole centered below them. The left slot is
Speaker 1: slightly larger than the right. The left slot is called neutral,
Speaker 1: the right slot is called hot, and the whole below
Speaker 1: them is called ground. The prongs on the plug fit
Speaker 1: into these slots in the outlet. In a house outlet,
Speaker 1: power flows from hot to neutral. Let's say you plug
Speaker 1: a light bulb into the let. The power will flow
Speaker 1: from the hot prong through the filament and back to
Speaker 1: the neutral prong, creating light in the process. The groundhole
Speaker 1: and the neutral slot of an outlet are identical. That is,
Speaker 1: if you go back to the fuse box, you'll find
Speaker 1: that the neutral and ground wires from all the outlets
Speaker 1: go to the same place. They all connect to ground.
Speaker 1: Since they both go to the same place, why do
Speaker 1: you need both. If you look around your house, what
Speaker 1: you'll find is that just about every appliance with a
Speaker 1: metal case has a three pronged plug. This may also
Speaker 1: include some things like your computer, that have a metal
Speaker 1: in case power supply inside, even if the device itself
Speaker 1: comes in a plastic case. The idea behind grounding is
Speaker 1: to protect the people who use metal and cased appliances
Speaker 1: from electric shock. The casing is connected directly to the
Speaker 1: ground prong. Let's say that a wire comes loose inside
Speaker 1: an ungrounded metal case and the loose wire touches the
Speaker 1: metal case. If the loose wire is hot, then the
Speaker 1: metal case is now hot and anyone who touches the
Speaker 1: metal case will get a potentially fatal shock. With the
Speaker 1: case grounded, the electricity from the hot wire flows straight
Speaker 1: to ground, and this trips the fuse in the fuse box.
Speaker 1: Now the appliance won't work, but it won't kill you either.
Speaker 1: What happens if you cut off the ground prong or
Speaker 1: you use a cheater plug so you can plug a
Speaker 1: three pronged appliance into a two pronged outlet. Nothing really happens.
Speaker 1: The appliance will still operate. What you've done, however, is
Speaker 1: you've disabled an important safety feature that protects you from
Speaker 1: an electric shock if a wire comes loose. Do you
Speaker 1: have any ideas or suggestions for this podcast? If so,
Speaker 1: please send me an email at podcast at how stuff
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