My textbook says that when theres a switch in a circuit it shouldnt' be in the nuetral wire, becuase the circuit will still be live, well i thought that if theres a break in the ciruit anywhere no current would flow or voltage present at all so surely it wouldn't matter where the swtich was?! answers much appreciated!
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Just because there's a break in the circuit does NOT mean that there's no voltage.
Example, you have a hot and neutral wire leading to a light socket. If you put the switch in the hot side, "before" the bulb, when you turn the switch off, the socket has no voltage, and if you stick your finger into it while you're grounded, no problem. If instead you put the switch in the neutral side, when you turn it off, the light won't come on, but you'll still have lines voltage at the socket, and if you happen to stick your finger in it, and you're somehow grounded, *zap*.
So, when doing wiring you always want switches in the hot wire to minimize the amount of "hot" wiring in whatever setup you have in case of an accidental connection or short circuit.
Example, you have a hot and neutral wire leading to a light socket. If you put the switch in the hot side, "before" the bulb, when you turn the switch off, the socket has no voltage, and if you stick your finger into it while you're grounded, no problem. If instead you put the switch in the neutral side, when you turn it off, the light won't come on, but you'll still have lines voltage at the socket, and if you happen to stick your finger in it, and you're somehow grounded, *zap*.
So, when doing wiring you always want switches in the hot wire to minimize the amount of "hot" wiring in whatever setup you have in case of an accidental connection or short circuit.
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Probably not a good idea to reverse connect the polarity on some devices.