A homophone for switch is "which."

Put all three wires from the one switch under one terminal.

An automatic transfer switch would be used when one needs to switch energy from one source to another and cannot do it manually. It can be used to switch from electric to a generator when needed.

Single pole toggle switch.

Disadvantages are :

1.The crossbar switch is singled-layered switch.

2.At each point,there is a switch when closed,connects one of the inputs to one of the outputs.