Wiring a light bulb with combo switch and outlet. The break away fin tab is intact therefore, line (hot) is connected to the (only) one brass terminal on line side. 2 way light switch with power feed via the light switch How is the wiring for a new light switch and fixture added to an existing switch? Single light switch wiring diagram . Light wiring diagram, two way switch, old cable colours. With the switch off, the line wires are not connected, and the light will be off. Phase (red or brown) should go to switch 1 (sw1) c , light (red or brown) should go to switch 2(sw2) c , neutrals (black or blue) should common together (loop). The ground screw is for the circuit ground wire connection. The wires are enclosed in an outer sheet and are flat twin&earth cables. Two way switching means you can switch the same light fixture from two switches that are located in different sides of a room. Single pole switch diagram #2 this switch wiring diagram shows the power s...