Museum of Plugs and Sockets
55 points - last Monday at 4:58 PM
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In our houses, there are circuit breakers. They don't protect you or devices, they can only protect wires in the wall, those who installed the wires knew how much current they can take and installed appropriate circuit breakers.
When you plug the plug in the wall socket, the circuit breaker has no idea what you plugged in so it cannot protect it, so there has to be a fuse in the plug, like in the UK plug. Whoever chose the wires for this device choose appropriate fuse.
There is one more case possible, the wire is not permanently attached to the device but via another socket, for example C14 socket like in PC. In that case manufacturer of the PC should know what kind of currents it is capable of handling and should put fuse inside it.
Now everything is protected (at least for over-current, if you touch live and neutral with two hands, 30mA through heart is enough to kill you but that's something that cannot be avoided, not even GFCI can do it).