3-way light switch with power feed via the light switch
Here we have a single light controlled by 3 way switches.
The hot from the power source connects to the common terminal of the first 3-way switch (SW1) and the neutral is spiced through (SB1) to the second 3-way switch (SW2) via the 3 wire cable (C2, that also carries the travelers that connect the two switches) where it is spliced through (SB2) to the neutral terminal of the light. The hot from the common terminal of the second 3-way switch (SW2) is connected to the hot terminal of the light.
Tags: 3 way light switch, 3 way switch, How to wire a light, how to wire a light switch, Power feed via switch, three way light switch, Three way switch, travelers