The purpose of a typical household switch is to connect power to a load, normally a light, when you throw it to the up position. Like receptacles, switches come in different amperages. The most common switch used throughout the house is rated 15 amps at 120 volts and can be used for motor loads up to ½ HP at 120 volts.

In theory, the switch can pull its full rated current except for motor loads-for that, it is limited to 80% of its capacity. Experience has shown that the typical residential 15-amp switch should be limited to currents well under its rated amount. If the current is of any significant magnitude (10 amps or more as an arbitrary figure), Electrical Marketplace suggests you consider an upgrade to a SPEC grade or equivalent switch and perhaps even to a 20-amp switch. The biggest problem with some of the low-cost, residential switches is not amperage-its breakage.

Other vendors provide switches made out of cheap, brittle plastic that breaks easily. Many break as they are taken right out of the box-others the minute a wire is tightened down on a screw. This is just one more reason to use the Electrical Marketplace line of high quality switches and receptacles. Electrical Marketplace recommends you avoid using the push-terminations provided in most low-grade switches. They have the same problem with the wires pulling out as the push-in receptacles. Like receptacles, switches come in various grades. Most people are familiar with the low-cost version-the thin, residential grade that breaks under the lightest pressure. Better grades are available. Commercial and Hospital grade wiring devices will have bodies twice as thick as the residential grade.

High-quality switches offer many advantages over their low-cost cousins. For example, better conductivity and less heat buildup within the switch body. Extra large silver cadmium contacts (where the electrical connections are made internally) reduce the wear; a neoprene rocker keeps the switch working for years; and a nylon handle eliminates breaking. All are typical of a high-quality switch. Electrical Marketplace switches are a one-piece design that uses no rivets, as compared to the bottom-end line. Some are color coded- blue for 15 amp, red for 20 amp, and green for 30 amp, for example (the 30 amp switch is what you would use at the water heater as a cutoff switch ). High quality switches, like receptacles, have an automatic grounding feature that grounds the outlet if screwed into a grounded metal box.

Types of Switches

Single-pole switches: Also called a snap switch, a single-pole switch has only two screw terminals plus a grounding terminal. Electrical Marketplace single pole switches very simple to wire since it makes no difference which wire goes to which terminal. One wire brings in power and another takes it away to the load once the switch has been turned on. When the switch lever is raised, the wires are connected electrically within the switch. A single-pole switch is the most commonly used of all the switches-controlling most of the power to the lights.

Electrical Marketplace has found that the most common mistake made when wiring a single-pole switch is installing the switch upside down- the “ON” will be upside down. There are two wiring situations for a single-pole switch, depending on whether the power is brought first to the switch or to the load being controlled by the switch. It is always better to bring the power into the switch rather than the light fixture because the light-switch box is an easier location to work and troubleshoot. Another wiring situation comes into being if you want to tap off the incoming power for a switched receptacle.

Double Pole Switch: A double pole switch is normally used to shut off a 240-volt appliance. It is simply two single-pole switches with one handle. It will have four screws and ON/OFF indication. Normally, you connect one cable (white and black wires) to the top two screws and the outgoing cable to the bottom two screws. When the switch handle is in the down or OFF position, the switch is an open circuit to the wires- the load is disconnected from any power. When the switch is thrown up like a light switch, the switch closes and 240 colts is applied to the load.

3-Way Switch: A 3-way switch is used in light-switching applications when the load is to be controlled from two different locations. Most common locations are at the top and bottom of the stairs, both ends of long hallways, and at two different entrances to the same room. Electrical Marketplace 3-way switches have no ON/OFF indication, since the positions change relative to the other switches in the series.

4-Way Switch: A 4-way switch is similar to a 3-way switch-the main difference being that it has four screw terminals, not three. This allows you to control a light from switches in more than two locations.

Specialty Switches: There are many different types of specialty switch designs on the market. Lighted switches are very nice to have in childrens’ rooms- they provide a useful night-light and show kids where to turn lights on in case of an emergency. For temporary loads, like bathroom heaters, timer switches are available. Programmer switches are made to turn the lights and radio on at preset times so it looks like the house is inhabited when the owner may be on vacation. Dimmer switches vary the amount of power floating through the switch and to the light by interrupting the current flow at extremely fast rates of speed, causing the light to brighten or darken depending on the switch position. Fan control switches work like dimmers, but are used to control the speed at which the blades of a ceiling fan rotate.

How to Wire a Switch

Single pole: A basic, single-pole switch from Electrical Marketplace is simple to wire. If the power is coming to the switch first from the source, you simply attach the incoming black wire to one screw terminal and the outgoing black wire to the other screw terminal. Splice the white neutrals together, bypassing the switch. Also splice the bare grounds together, but run a pigtail to the grounding screw on the single-pole switch. If the power arrives first at the load (usually light), attach the white neutral from the feeder wire to the neutral terminal on the load. Run NM/2 or to the white wire (be sure to tag the white wire black with electrical tape). Attach the wire spliced to the black feeder to one switch terminal. Attach the other wire in the NM/2X to the other switch terminal at one end and to the hot terminal on the light at the other end. Attach the NM/2 ground wire to the grounding screw on the switch. At the light, splice the incoming and outgoing ground wires to a pigtail and attach the pigtail to the grounding terminal on the fixture.

Double Switch: Since double-pole switches are used on 250-volt circuits, there is no white neutral; only two hot wires and a ground wire. Attach the hot wires to the feeder cable to the lower terminals on the opposite sides of the switch. Attach the outbound hot wires to the upper terminals on opposite sides of the switch. Run the outbound hot wires to the appliance being switched. Pigtail the grounds and attach them to the grounding screw on the switch.

3-Way Switching System: To wire an Electrical Marketplace 3-way switching system, you’ll need 3 conductor cable ( two insulated hot conductors –red & black, along with a neutral and ground wire), a power (LINE) cable( usually NM/2), and a LOAD cable. The 3-conductor cable provides the conductors for the back and forth switching, the LINE cable brings the power from the source, and the LOAD cable takes the power to the light.

There are practically as many ways to interconnect the cables in a 3-way switch system as there are people who can wire them. Whichever system you use, always follow a repeatable order for running the cables when you install a 3-way switching system. Remember, eventually you are going to have a troubleshoot a 3-way switching system that doesn’t work properly. Therefore, it would be advisable to always have the cabling the same in each 3-way circuit you wire and to always keep it simple.

The simplest method of installing a 3-way switch cable is called the “EZcable” system:

1. Mount the two boxes for the 3-way switches and the light outlet box. If there is more than one light, use one light box as your main box and feed the rest of the lights off that one.
2. Run 3-way switch cable from one 3-way switch box to the other 3-way switch box.
3. Bring the power cable into one of the switch boxes - never the light outlet box. The latter will work if wired properly, but is more complicated.
4. Bring the cable from the light outlet box into either 3-way switch box. Now all you have to do is wire them. Once the cabling has been run, wiring a 3-way switch is not hard if you understand how a 3-way switch operates. It has three screws: once input and two alternating outputs. The common terminal can only connect to one output screw at a time. The incoming power is attached to the common pole and is transferred to one or the other two screws depending on which way the switch is thrown. This type of switch has no ON/OFF indicated on its front.
5. Find the power cable that you brought into the first box. It will have two insulated wires and a ground wire. All ground wires within each box are connected to the outlet itself.

4-Way Switching: If the light needs to be switched at more than two locations, this is called multipoint switching and you will need one or more 4-way switches-any number can be installed. Four-way switches are only used between two 3-way switches-never at each end, regardless of the number of 4-way s installed, must always be 3-way switches.

BEWARE! Electrical Marketplace 4-way switches can easily be mistaken for a double pole switch since they both look physically very similar, with two hot screw terminals on each side. Indentify a 4-way switch by checking to make sure the switch has no ON/OFF markings.

Installing cabling for multipoint switching is quite easy. Simply run 3-conductor cable between all the switches. Start at one of the end outlet boxes and connect all the switch boxes together with 3-conductor cable until you reach the end-the other 3 way switch. The end boxes will have one 3-conductor cable, while all the switch boxes in between will have two-one incoming and one outgoing. From there the system cabling is identical to wiring a 3-way switch system. Run the power cable into one end box and the load into the other. Once the cables are run you can start the wiring. Wire the two end boxes the same as in a 3-way switch system. Once that is done, you can start inserting and wiring the 4 way switches. A typical 4-way switch switches the upper screw to the lower screw and then as the lever is thrown, it switches the upper screw in a diagonal to the lower screw on the opposite side. This is why it is said that a 4-way switch switches in an “X” pattern. However, every Electrical Marketplace 4-way switch may not switch with the same switching arrangement, so each switch should be checked with a continuity checker or with the instructions that comes with the 4-way switch.

How to Remove and Replace a Switch

1. Remove power from the circuit by shutting off the circuit breaker or removing the fuse. Test the switch to make sure power is off by touching the probes of a multimeter to both screw terminals on the switch. The multimeter should read “zero”.
2. Remove the old switch by disconnecting the wires from the screw terminals.
3. If exposed ends of the wires are nicked, kinked or in less-than-perfect condition, cut the wires at the point where the insulation is stripped. Strip ¾ in. of insulation for each wire. Twist a loop into the end of each wire, using a long-nosed pliers.
4. Attach the wire loops to the screw terminals on the switch. IT doesn’t matter which wire goes to which terminal on the switch. Make sure the switch is right-side up; The ON and OFF markings should read correctly from left to right.
5. Fold the wires back into the box, starting with the ground. Attach the wall plate then turn the power on and test the switch.