4weg

4weg, short for four-way switch, is a term used in Dutch-speaking electrical installations to describe a four-terminal switch used in multi-location lighting circuits. In such circuits, it is placed between two three-way switches to enable control of a light from three or more locations. The device itself does not create an on or off state; instead it reconfigures the path of current between two traveler pairs, allowing users to change which path completes the circuit.

Construction and operation: A 4weg has four terminals, typically arranged as two pairs. Internally it can connect the left pair to the left and the right pair to the right (straight configuration) or cross-connect left to right (criss-cross) depending on the lever position. In many designs the switching action is mechanical, using a toggle, slide, or other actuator to switch between these two internal connections. The exact terminal labeling and arrangement vary by manufacturer, but the basic function remains the same: it alternates how two pairs of traveler wires are connected.

Wiring and typical use: In a standard arrangement, two end switches are three-way switches, and the 4weg sits between them. The lamp is controlled by the combination of the end switches, so flipping any of the switches can turn the light on or off. More than one 4weg can be inserted in series to enable control from additional locations, preserving multi-location control without introducing a separate on/off mechanism at the intermediate units.

Applications and context: 4weg switches are common in residential stairways, long hallways, and other spaces where multiple entrances require lighting control. They are part of multi-way switching systems found in European wiring practices and are used in both simple and commercial installations.