Electrical Basics ~ How Does A Switch Work?

The "switch", we use them daily, to turn on and off lights or dispose of last night's dinner. A simple, yet powerful device, capable of controlling any situation... with just the flip of a switch. 

From the "single pole", to the "three way"...switches, they all serve the same function. To control the flow of "electric current", from the power source, to the end load. Such as a lamp or appliance. By closing the switch, the current flows along the wired path. Then, the "load" is instantly energized, and the current returns to the source, completing what is called a "circuit".

Keeping in mind that the "source" is both, the starting point and the return point of an electrical circuit, you can use that knowledge to map any switching situation.

How Does A Switch Work? ~ The Single Pole

The single pole switch is, most often, used to control a light fixture, from a single location. Other loads, such as a garbage disposal, may also be controlled by using a single pole switch.

Internally, there is a blade that pivots from a fixed pole. From either an open or closed position. In the closed position, the blade makes contact with the other pole on the swtich and current is allowed to flow through the switch.

How Does A Switch Work? ~ The Three Way

Like a single pole switch, the three way switch also directs the currents flow but in a slightly different way. By adding a additional "pole" to the switch, there is now an extra path for current to flow. The switch pivots from the "common pole" between these poles on the switch. Now, when used in tandem with another three way switch, they allow for a light fixture to be controlled from two locations. Such as a residential hallway or common areas with two entry points. 

This is done by wiring the switches together using a system of "travelers". Typically, the travelers will be the black and red conductors,that are ran using a "3-wire NMB cable", between the three ways. 





How Does A Switch Work? ~ The Four Way

So, the three way was pretty cool but wouldn't it be nice to control a light from more than just two locations? 

Absolutely! That's where the four way switch comes in. They allow for the switching of 2 sets of travelers in between the "2" three way switches. Again, common applications would be a residential hallway or areas with multiple entries. Keep in mind that it only takes "2" three ways, regardless of the number of four-way switches used.