ECM 111 chapter 13

. One of the screws is called the

"common" terminal and is usually colored black

Switching of receptacles can be done so the whole receptacle is switched on or off, or the wiring can be installed so that half a duplex receptacle is energized with the switch while the other half remains

"hot" at all time

. It is common wiring practice to switch the bottom half of the receptacle and leave the top half

"hot" at all times

On the other hand, if the top half were switched and a lamp cord plugged into it, the cord would hang down in front of the

"hot" half of the duplex receptacle and be in the way when another piece of electrical equipment needed to be plugged into that half

The traditional switch loop arrangement will require the white wire in the cable to be used as a

"hot" ungrounded conductor

. On a single-pole switch, two wires will be connected to the two terminal screws on the switch. Both of these wires are considered

"hot" ungrounded conductors

Dimmer switches should never be connected to a

"live" electrical circuit

The double-pole switch also has markings that indicate the

"load" and the "line" sides of the switch

witching of receptacles can be done so the whole receptacle is switched on or off, or the wiring can be installed so that half a duplex receptacle is energized with the switch while the other half remains "hot" at all times. This is accomplished by

"splitting" a duplex receptacle

The other two terminal screws are the same color, usually brass or bronze, and are called the

"traveler terminals."

. For those wiring situations when a switch is needed to control a 240-volt load a

, double-pole (also called two-pole) switches are used

Section 404.14(A) categorizes one switch type as an "alternating current general-use snap switch" and states that it is suitable for use only on

alternating current circuits

Switched receptacles are often found in areas such as

bedrooms, living rooms, and family rooms of homes

Usually the "line" set of terminals is colored

black

One three-way switch will have a

black "hot" feed conductor attached to it

Assuming the use of a nonmetallic sheathed cable, when the power source feed is brought to the first three-way switch in the circuit, the traveler wires that interconnect the traveler terminals of all four-way and three-way switches will be

black and red in color

The black-colored "common" terminal on a three-way switch should always have a

black insulated wire attached to it

d the "load" set of terminals is colored a

brass or bronze

a device with more than one switch type on the same strap or yoke

combination switch

Many residential lighting circuits are wired with 14 AWG conductors protected with a 15-ampere circuit breaker and will require switches with a 15-ampere, 120-volt rating. This switch rating is the most

common found in residential wiring

If you are wiring with conduit, three separate wires must be pulled into the

conduit between the two three-way switches

a switch type that raises or lowers the lamp brightness of a lighting fixture

dimmer switch

Section 404.2(B) actually says that switches must not

disconnect the grounded conductor of a circuit

a switch type used to control two separate 120-volt circuits or one 240-volt circuit from one location

double pole switch

Assuming the use of a nonmetallic sheathed cable, when the power source feed is brought to the

first three-way switch

A three-wire cable must always be installed between all

four-way and three-way switches

a switch type that, when used in conjunction with two three-way switches, will allow control of a 120-volt lighting load from more than two locations

four-way switch

Only traveler wires are connected to the

four-way switch screw terminals

Switches that are used to control lighting circuits are classified as

general use snap switches

Both single-pole and three-way dimmer switches will also have a

green insulated grounding pigtail

One of the drawbacks to using a traditional switch loop is that there will not be a

grounded circuit conductor at the switch location

However, pilot light switches and electronic devices like occupancy sensors typically need a

grounded conductor connected to them for proper operation

No switching in the

grounded conductor is allowed

Garages, attics, crawl spaces, closets, and unfinished basements are examples of areas where a

grounded conductor is not required at the switch location and a traditional switch loop can be installed

So, switch boxes installed on studs with a basement under or an attic above would qualify as areas where the

grounded conductor would not have to be installed

A common switch style for a ceiling-suspended paddle fan/light. The single-pole switch controls the

lighting fixture attached to the paddle fan, and the rotary switch provides three-speed control of the paddle fan

Another factor to consider is the number of switching locations for the

lighting load on the circuit

. Three-way switches (Figure 13-3) are used to control

lighting loads from two separate locations, such as at the top and bottom of a stairway

. An example of this requirement would be a living room that has three switch locations consisting of two three-way switches and one four-way switch. All of these switch locations are located in the

living room

ike the single-pole switch, the double-pole switch can control the load from only one

location

The rotary switch is used to control the paddle fan. It has three specific speed settings

low,medium,high

Nonmetallic sheathed cable (Type NM) and nonmetallic boxes are shown in the following single-pole switching illustrations because they are used the

most in house wiring

a device that upon detecting movement in a specific area will switch on a lighting load; once all movement stops and a short amount of time goes by the device switches off the lighting load; often used for outdoor lighting control in residential applications

motion sensor

a device that detects when a person has entered a room and switches on the room lighting; when everybody leaves a room and a short amount of time goes by the sensor device switches the room lighting off; often used for automatic control of room lighting in residential applications

occupancy sensor

Like single-pole and three-way switches, four-way switches work by having their

open or closed

The rotary switch is used to control the

paddle fan

Three-way switches must always be installed in

pairs there cannot be one

Section 404.14 states that switches must be used within their

ratings

The most common switch type used in residential wiring is a

single pole switch

a switch type used to control a 120-volt lighting load from one location

single pole switch

A dimmer switch (Figure 13-5) can be found in both a

single-pole and a three-way configuration and is used to brighten or dim a lamp or lamps in a lighting fixture

Dimmer switches are used in residential wiring applications to provide control for the brightness of the lighting in a specific area of a house. They are available in both

single-pole and three-way models

three-way switch is sometimes called a

single-pole double-throw switch (SPDT)

The NEC® and Underwriters Laboratories refer to the switches used to control lighting outlets in residential applications as

snap switches

Single-pole switches either let current flow through the

switch and to the load or do not

In addition, this section also states that if the conductors enter the

switch box through a raceway and a new grounded conductor could be installed in the raceway at a later date, a grounded conductor does not need to be installed

The speed of the paddle fan will need to be set by a

switch located on the fan itself in this switch arrangement

Ceiling-Suspended Paddle Fan/Light,The power source will feed the

switch location

Section 404.2(C) requires a grounded conductor be installed at the

switch location in bathrooms, hallways, stairways, or in any room suitable for human habitation or occupancy

a switching arrangement in which the feed is brought to the lighting outlet first and a two-wire loop is installed from the lighting outlet to the switch

switch loop

The switch on the table or floor lamp is left in the ON position, so when a switch is activated and energizes the receptacle that the

table or floor lamp is plugged into, the lamp comes on

Dimmer switches are used in residential wiring applications to provide control for the brightness of the lighting in a specific area of a house. They are available in both single-pole and three-way models. They differ from regular switches because they do not have

terminal screws on them

four-way switches (Figure 13-4) allow for control of lighting loads from

three or more locations, such as in a room with three doorways

You may remember that three-way switches have

three terminal screws on them

a switch type used to control a 120-volt lighting load from one location

three way switch

Four-way switches are used in conjunction with

three-way switches to control a lighting load from more than two different locations

Sometimes it is desired to continue an unswitched part of a circuit "downstream" of a switched lighting outlet. To accomplish this, a

three-wire cable is used between the switch location and the lighting outlet

a device that controls the flow of electricity on a circuit for a certain amount of time; used in residential applications to switch off a bathroom fan or ceiling-suspended paddle fan after a specific length of time has gone by

timer

There is no marking for the ON or OFF position of the

toggle on a three-way switch

It is very common for residential electricians to run the power source to the lighting outlet first and to then run a two-wire cable to the single-pole switching location. This is called a

traditional switch loop

Installing Four-Way Switches,All four terminal screws are called

traveler terminals

the traveler wires that interconnect the

traveler terminals of both switches will be black and red in color

Single-pole dimmers have

two black insulated conductors

Three-way switches are used to control a lighting load from

two different locations

Three-way dimmer switches typically come from the manufacturer with

two red insulated pigtails and one black insulated pigtail

Combination switch (Figure 13-6) devices consist of

two switches on one strap or yoke

On a single-pole switch, two wires will be connected to the

two terminal screws on the switch

A three-wire cable must always be installed between the

two three-way switches

Four-way switches must always be installed between

two three-way switches

For example, if you wire a switching situation that requires four switching locations for the same lighting load, you would need

two three-way switches and two four-way switches

Section 404.2(A) of the NEC® requires three- and four-way switches to be wired so that all switching is done in the

ungrounded "hot" circuit conductor

Switches are to be wired so that all switching is done in the

ungrounded circuit connector

One factor that electricians base their switch selection on is the

voltage and current rating of the circuit that the switch is being used in

When wiring a house with nonmetallic sheathed cable, a two-wire cable is available with only a

white insulated conductor and a black insulated conductor

electrical loads in a house can operate on

120 volts, 120/240 volts, or 240 volts

Type NM is available as a four-wire cable in

14/4 and 12/4 styles from some manufacturers

A double-pole switch (Figure 13-2) is used to control a

240-volt load in a residential wiring system, such as an electric water heater

Three-Way Switching Circuit This switching circuit is drawn with a metal

4 × 2⅛ inch octagon box at the lighting outlet