A switch is nothing more than a device to cut off or allow the flow of electrical current. When the switch is flipped or turned to the off position, the inner metal contacts separate, breaking the circuit and stopping electrical flow. Flip the switch back on and the contact is remade, allowing the current to flow again.
There is a wide variety of switches available, but most common are house switches.
Many of the things that can be said about receptacles ,can also be said about switches. Like receptacles, switches are designed to handle specific electrical loads. Commonly, switches come in 15- and 20-amp sizes. This means that the contacts in them can handle up to 15 or 20 amps of current without being overloaded.
Twenty-amp switches are known as "spec" or specification grade and are not only higher amperage but better made. If you plan to use the switch frequently, such as in a bath or kitchen, the spec grade is justified. Though it costs more, it will last much longer than regular grade. Switches come in white, ivory, and brown.
House switches are often ref erred to as "single pole" switches, which means that they interrupt the "hot" side of the circuit. "Double pole" means that they interrupt both hot and neutral sides of one circuit, or each "hot" side of two circuits, say a pair of 110-volt circuits connected together to yield 220 volts.
Most switches have screw terminals -- brass, silver, or green-colored screws on which wires are wrapped to make electrical connections -- as well as holes in the back or side for clamp connections. Wires can be pushed into these holes and clamped in place, rather than having to be wrapped around screws. Having clamp holes as well as screws allows you that much more capacity for accommodating the wiring connection you want to make. The holes are coded and are an integral part of the connections to screw terminals.
Switches have three kinds of on/off action, ranging from loud to silent: some switches make a distinctive click when you hit them; in others you can hear the switch, but just barely; there is also a type called a mercury switch, which is silent. The quieter the switch, the more you'll pay for it. Switches can be found on which the toggles are illuminated, handy for finding a switch in the dark.
Like receptacles, switches have metal stampings on top with tapped screw holes for ready attachment to a box, and ears so you can install the switch flush with the wall material.
In addition to house switches, there are a number of other useful switches.
ELECTRICAL HOME HARDWARE SECTION
Description of Contents
OTHER HARDWARE SECTIONS
GENERAL HARDWARE SECTION
ADHESIVES, PATCHES & MORE