A 3-way lamp Explained

A 3-way lamp, also known as a tri-light, is a lamp that uses a 3-way light bulb to produce three levels of light in a low-medium-high configuration. A 3-way lamp requires a 3-way bulb and socket, and a 3-way switch. Unlike an incandescent lamp controlled by a dimmer, each of the filaments operates at full voltage, so the color of the light does not change between the three steps of light available.

Certain compact fluorescent lamp bulbs are designed to replace 3-way incandescent bulbs, and have an extra contact and circuitry to bring about similar light level. In recent years, LED three way bulbs have become available as well.

Lamp bulbs with dual (carbon) filaments were built as early as 1902 to allow adjustable lighting levels.[1] Large lamps of 500-watt rating were used for street lighting in France, which had a second filament at 200 watts to reduce lighting costs. In 1933 in the United States, Westinghouse announced a dual-filament lamp for commercial lighting and a smaller lamp for residential use

In building wiring, multiway switching is the interconnection of two or more electrical switches to control an electrical load (often, but not always, lighting) from more than one location. For example, this allows lighting in a hallway, stairwell, or other large rooms to be controlled from multiple locations.

While a "normal" light switch needs to be only a single pole, single throw (SPST) switch, multiway switching requires the use of switches that have one or more additional contacts and two or more wires must be run between the switches. When the load is controlled from only two points, single pole, double throw (SPDT) switches are used. Double pole, double throw (DPDT) switches allow control from three or more locations.

In alternative designs, low-voltage relay or electronic controls can be used to switch electrical loads, sometimes without the extra power wires.

3 Way Switches Explained - How to wire 3 way light switch

How to wire 3 way light switch, in this video we explain how three way switching works to connect a light fitting which is controlled with two light switches. We look at the US color coding wires and explain the different ways to connect the lighting circuit.

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