Three-Way (Switch Parallel): What is it? How it works?

It is very important to consider the need to control one lamp or more in the same spot, over a different location. In these cases we use a set of parallel switches, also known as "Three Way." That switch also provide greater comfort for the user, raises issues regarding safety, due to be in charge of lighting more than one item. Example: In a corridor or a stairway, it is good to have a switch at each end connected to the same lamp. This allows a person to light the lamp to come in and delete it when you reach the other end of the stairway or hallway.
The living rooms, bedrooms (one on each side of the bed helps the good relationship), hallways, kitchens, lighting outside, etc..

(Fig 01: Example of application of a Three-way switch or Parallel)

(Fig 02: Outline drawing of connection with the respective type of driver - click on picture to enlarge)

In figure 02 we have two types of connections, right and wrong. Note that the switches always slice the stage, never neutral, as required by the NBR 5410, to prevent electric shock in the exchange of light bulbs with this fire. Note the existence of the return conductor, the so-called phase after being sectioned.

1) The neutral conductor is connected at one point in the lamp receptacle;
2) The driver stage should be connected to a switch from Parallels, the center pin. The other two pins of the switch, drivers should leave two of Return, to the other parallel switch;
3) the center pin of the second parallel switch, you will leave the other driver of return, which should be connected at the other pole receptacle for the light, thereby completing the electrical circuit.

We can see in more detail in the figure below:

(Fig: 03 Connection of Three-Way)

(Fig 04: Symbolism of the Three-Way)