This circuit diagram shows wiring for a 4 way circuit with the power source at the light fixture and the switches following.
A two-wire cable (C2) is run from the light to the first switch (SW1) and a 3-wire cable runs between all the switches. The hot source is connected to the common terminal on the first switch (SW1) and the hot terminal on the light fixture is spliced through all the light fixture to the common terminal of the last switch (SW3).
The travelers run from the first switch (SW1) to one set of terminals on the 4 way (SW2) and from the second set to the travelers on the last 3 way (SW3). The hot to the light is from the common terminal of SW3 (spliced through each switch box).
The power for the circuit joins the light fixture F1 via the cable C5. The neutral connects to the light (LT1) and is spliced through to LT2 via the cable C4. The hot from the power source is spliced through to the common terminal of the switch (SW1) via cable C1.
The travelers from the switches, via C1 and C2, are spliced through the fixtures,and joined by cable C3.
The power, cable C1, joins the circuit at the light fixture F1. Here the neutral connects to the light F1 and is spliced through to light F2. The hot from the power source is spliced through both fixtures and terminates at the common terminal of SW1 via cable C3.
The travelers of each switch are connect together using cable C4 (taped white and red wires).
The power source in this circuit enters the light fixture where the neutral connects to the light and the hot is spliced through (via cable C2) to the common terminal of the 3-way switch (SW2). The travelers between the switches are also spliced together in the light fixture. The power to the light is via the common terminal of the 3-way switch SW1.
In this light switch wiring diagram the power feed joins the circuit via the light fixture where a two wire cable (C2) runs from the light, to the first 3-way switch (SW1), and a 3 wire cable (C3) joins the two switches. The hot source is spliced to the white wire (which should be marked as being hot with black tap) and run through to the common terminal of SW1, and from here the hot from the light is spliced through to the common terminal of the second 3-way switch (SW2).
The power source enters the light fixture where the neutral connects directly to the neutral terminal of the light. The hot wire from the source is spliced through to the 2-way switch and via the switch to the hot terminal of the light.