Speaker 1: Welcome to brain Stuff from house stuff works dot com
Speaker 1: where smart happens. Hi Am Marshall Brain with today's question,
Speaker 1: why do the two flat prongs on plugs for most
Speaker 1: electrical appliances have holes in them? If you unplug any
Speaker 1: appliance in your house, there's a nine percent chance that
Speaker 1: the two flat prongs have holes in them. There are
Speaker 1: three reasons for those holes. First, if you were to
Speaker 1: take a part in outlet and look at the contact
Speaker 1: wipers that those prongs slide into, you would find that
Speaker 1: they have bumps on them. These bumps fit into the
Speaker 1: holes so that the outlet can grip the plugs prongs
Speaker 1: more firmly. This detenting prevents the plug from slipping out
Speaker 1: of the socket due to the weight of the plug
Speaker 1: in the cord. It also improves the contact between the
Speaker 1: plug and the outlet. Second, electrical devices can be factory
Speaker 1: sealed or locked out by the manufacturer or owner using
Speaker 1: a plastic tie or a small padlock that runs through
Speaker 1: one or both of those prong holes. For example, a
Speaker 1: manufacturer might apply a plastic band through the hole and
Speaker 1: attach a tag to it that says you must do
Speaker 1: blah blah blah before plugging in this device. The user
Speaker 1: can't plug in the device without removing the tags, so
Speaker 1: the user is sure to see the instructions. Third, there's
Speaker 1: also a small savings and raw materials for the manufacturer
Speaker 1: of the actual plug prong. Every little bit helps. It's
Speaker 1: been reported that really old outlets used captive ball bearings
Speaker 1: in coil springs for the detent, but today it's done
Speaker 1: with a bump on a springy copper contact. 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
Speaker 1: works dot com. For more on this and thousands of
Speaker 1: other topics, go to how stuff works dot com and
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