What is a switch live wire?
Also know, why is switch in live wire?
A switch in the electrical circuit is always connected to the live wire so that the socket/appliance is not live when it is switched off. The thicker the wire the more current is needed to melt it and the higher the 'rating' of the fuse.
Likewise, should switch be on live or neutral? Live is live. A connection from neutral to ground will not likely kill you, but a connection from live to ground stands a decent chance of doing so. And more of the circuit is live than neutral if you switch only the neutral, including any electrical devices on the circuit.
Simply so, where does the switch live wire go?
The permanent live wire is wired into the switch and the switched live into the switched live terminal. The neutrals are connected together using a terminal connector. You can also see that another live and neutral wire go to the next light switch.
Which wire is load and which is line?
Line is the side of the device where the wires from the panel (or other equipment feeding the device) are connected. Load is where any devices that are to be protected by the GFCI device are connected. Most "newer" GFCI devices will not reset if they are not connected probably.