120 V enters the light fixture outlet box.
No longer allowed after 2011 NEC (if no neutral wire in switch boxes)
120 V enters the first 3-
In the diagram below, a 2-
The common terminal of the second 3-
The white neutral wires are connected together in each switch box.
Diagrams shown on this page are simplified for clarity. Electrical outlet boxes can have numerous NM cables going in and out. See Actual Switch Box Wiring. Ground connection diagram is shown separately.
With conventional wiring, 120 volts enters the first 3-
Black common wire is usually wrapped around the two traveler wires on a 3-