3 Way Switch Voltage. They are also available in the same types of switches: incandescent, fluorescent, LED, low voltage, and multiple load. The upstairs is dark, and as she flips the switch.
Turn off the power for the circuit at the breaker box. For starters, it doesn't have "OFF" and "ON" printed on the toggle. They are always installed in pairs and use special wiring connections.
Three-way light switches control a light from two locations, such as from both ends of a staircase or hallway.
The safest way is to use a non-contact voltage tester.
Three-way switches are also common in hallways, garages, and kitchens. The common is usually connected to the black screw (should be marked common) on the. The upstairs is dark, and as she flips the switch.