If we have AC Current coming into our homes, then why we have different coloured wires?
In: Physics
Because one of the wires is at the same potential as ‘earth’ or ‘ground’, and you want to know which one that is. Technically you could touch the neutral wire with one hand and for example a metal pipe in your house with the other and nothing would happen.
If you do the same with the other (hot) wire, you’d get shocked. Light switches for example are supposed to switch the hot wire, not the neutral one, because otherwise a light fixture that’s turned off at the switch would still potentially be dangerous to work on.
The core idea here is that voltage is always relative. If you take an AA battery and you touch the negative terminal of it to a metal pipe in your house, then the positive terminal of the battery is now at +1.5V relative to the (earthed) pipe. But if you touch the pipe with the positive terminal instead, the negative terminal would be at -1.5V relative to the pipe and earth.
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