If you wish to examine the full patent. Author: Patrick J. Chapter Doubtful Devices. This chapter covers a number of devices which either are The white neutral wire should be available in the grounding wire. The black wires are wire should be labeled with black tape switch box.
The terminals on the switch. The white wires grounding wire is connected to the are neutral and are joined together with switch grounding screw.
Grounding wires are pigtailed to the switch. Three-way switches are always installed in pairs and are used to control a set of lights from two locations. One of the screw terminals on a three-way switch Traveler screw is darker than the others. This screw is the common terminals screw terminal.
The position of the common screw terminal on the switch body may vary, depending on the manufacturer. Before disconnecting a three-way switch, always label the wire that is connected to the common screw terminal. It must be reconnected to Common screw the common screw terminal on the new switch. The traveler terminals are interchangeable, so there is no need to label the wires attached to them. Grounding screw Because three-way switches are installed in terminals pairs, it sometimes is difficult to determine which of the switches is causing a problem.
The switch that receives greater use is more likely to fail, but you may need to inspect both switches to find the source of the problem. The black wire from the two-wire cable is connected to the dark common screw terminal. The red and black wires from the three-wire cable are connected to the traveler screw terminals.
The white neutral wires are joined together with a wire connector, and the grounding wires are pigtailed to the grounded metal box. Holding the the grounded metal box or to the bare copper grounding wire mounting strap carefully, pull the switch from the box.
Be careful and touching the other probe to each screw terminal. Tester not to touch the bare wires or screw terminals until they have should not glow. If it does, there is still power entering the box. On most three-way switches, wires are interchangeable and can be Disconnect wires and remove switch. Test the switch for continuity.
If it tests Or it may be labeled with the word Carefully tuck the wires into the box. If necessary, clip switch. Reconnect the grounding screw, cover plate.
Turn on the power at damaged wires and strip them. Four-way switches are always installed between a pair of three-way Line 1 screw terminals switches. This switch combination makes it possible to control a set of lights from three or more locations. Four-way switches are common in homes where large rooms contain multiple living areas, such as a kitchen opening into a dining room. Switch problems in a four-way installation can be caused by loose Line 2 screw connections or worn parts in a four-way switch or in terminals one of the three-way switches facing page.
In a typical installation, there will be a pair of three-wire cables that enter the box for the four-way switch. With most switches, the white and red wires from one cable should be attached to the bottom or top pair of screw terminals, and the white and red wires from the other cable should be attached to the Note: Position remaining pair of screw terminals. However, not all of the screw terminals on a switches are configured the same way, and wiring switch may vary, configurations in the box may vary, so always study the depending on manufacturer.
The red Switch variation: Some four-way switches have a wiring and white wires from one cable are attached to the top pair guide stamped on the back to help simplify installation.
For the of screw terminals, while the red and white wires from the switch shown above, one pair of color-matched circuit wires other cable are attached to the bottom screw terminals. In will be connected to the screw terminals marked LINE 1, while new switch wiring, the white wire should not supply current the other pair of wires will be attached to the screw terminals to the switched device, and a separate neutral wire should be marked LINE 2.
Holding the mounting strap carefully, pull the switch from them for nicks and scratches. If the box. Be careful not to touch any bare wires or screw terminals until they have necessary, clip damaged wires and strip been tested for power. Test for power by touching one probe of the neon circuit tester them. Test the switch for continuity to the grounded metal box or bare copper grounding wire and touching the other pages 98 to Buy a replacement if probe to each of the screw terminals.
The tester should not glow. If it does, there is still the switch tests faulty. Return to the panel, and turn off the correct circuit. Pigtail the grounding wires to the grounding screw. Carefully tuck the wires inside the switch box, and then remount the switch and cover plate. Turn on power at the panel. It is used to control two light fixtures or appliances from the same switch box. In most installations, both halves of the Tab switch are powered by the same circuit.
In these single-circuit installations, three wires are connected To fixtures to the double switch. One wire, called the feed Ground wire which is hot , supplies power to both halves of the switch. The other wires, called the switch leg, carry power out to the individual light fixtures Feed or appliances.
In rare installations, each half of the switch Single-circuit wiring: Three black wires are attached to the is powered by a separate circuit. In these switch. The black feed wire bringing power into the box is connected to the side of the switch that has a connecting tab. The white neutral wires are connected photo below. Connecting tab To fixture Tab removed Ground Feed Separate-circuit wiring: Four black wires are attached to the switch.
Feed wires Remove the connecting tab on from the power source are attached to the side of the switch that has a connecting a double switch when wired in a tab, and the connecting tab is removed photo, right.
Wires carrying power from the separate-circuit installation. The tab can switch to light fixtures or appliances are connected to the side of the switch that be removed with needlenose pliers or does not have a connecting tab. White neutral wires are connected together with a a screwdriver. Pilot-light switches often are installed for Silver convenience if a light fixture or appliance cannot be seen from the switch location.
Basement lights, garage lights, and attic exhaust fans frequently are controlled To fixture by pilot-light switches. Gold A pilot-light switch requires a neutral wire Grounds connection. A switch box that contains a single two-wire cable has only hot wires and cannot be fitted with a pilot-light switch. Feed wire Pilot-light switch wiring: Three wires are connected to the switch. One black wire is the feed wire that brings power into the box.
It is connected to the brass gold screw terminal on the side of the switch that does not have a connecting tab. The white neutral wires are pigtailed to the silver screw terminal. The black wire carrying power out to a light fixture or appliance is connected to the screw terminal on the side of the switch that has a connecting tab.
In the most common installations, the receptacle is hot even when the switch is off photo, right. One of the hot wires is the feed wire that terminal on the side of the switch that does not have a brings power into the box. It is connected to the side of the connecting tab.
The other hot wire carries power out to the light fixture or appliance. It is connected to the brass screw terminal on the side that does not have a connecting tab. The white neutral wire is pigtailed to the silver screw terminal. Dimmer switches pages 96 to 97 are used frequently to control light intensity in dining cannot be installed in switch boxes that have only one cable with two hot wires. Timer switches and time-delay was changed in to require an available neutral switches below are used to control light fixtures wire in newly-installed switch boxes.
Electronic switches If a specialty switch is not operating correctly, you provide added convenience and home security, and may be able to test it with a continuity tester.
Timer they are easy to install. Electronic switches are switches and time-delay switches can be tested for durable, and they rarely need replacement. Most specialty switches have preattached wire With electronic switches, the manual switch can leads instead of screw terminals and are connected to be tested for continuity, but the automatic features circuit wires with wire connectors. Some motor-driven cannot be tested. The remaining wire lead is the fans on and off automatically once each day.
They are neutral lead. It must be connected to any neutral commonly used to control outdoor light fixtures. A switch box that contains only one Timer switches have three preattached wire cable has no neutral wires, so it cannot be fitted with leads. The black wire lead is connected to the hot a timer switch. Countdown timer switch.
This Occupancy sensor. Many smart Programmable timer switch. A rocker-type switch gives you the option switches incorporate a motion detector dial-type timer allows you to program to easily program the switch to shut that will switch the lights on if they the switch to turn on for specific time off after a specified time: from 5 to 60 sense movement in the room and will periods at designated times of day minutes.
Garage lights or basement also shut them off when no movement within a hour cycle. Security lights, lights are good applications: anywhere is detected for a period of time. The space heaters, towel warmers, and you want the light to stay on long model shown above also has a dimmer radiant floors are typical applications.
These switches often are used to control vent fans. This lets you turn on lights, heat lamps, Spring-wound timer switch. A relatively simple device, this and other loads for a designated amount of time 10 to 60 timer switch functions exactly like a kitchen timer, employing a minutes with one easy push of a button.
The green LED at hand-turned dial to and spring mechanism to shut the switch the bottom of this unit provides a readout of how much time off in increments up to 15 minutes.
The model shown is not compatible with fluorescent ballasts. Daylight sensor switch. This switch automatically turns on Backlit countdown timer. This digital switch lets you when light levels drop below a proscribed level. It can also be program lights or other devices to stay on for up to 24 hours programmed as an occupancy sensor to shut off when the and then shut off automatically. The backlit, LED readout gives room is vacant and turn on when the room is entered.
Up and down buttons let you raise or lower the remaining time easily, and a manual override button will shut off the switch until it is turned back on. Dimmers are often installed in dining rooms, recreation areas, or bedrooms.
Toggle-type dimmers Any standard single-pole switch can be replaced resemble standard with a dimmer, as long as the switch box is of switches. Toggle dimmers are available adequate size. Dimmer switches have larger bodies in both single-pole and three-way designs. They also generate a small The model shown amount of heat that must dissipate. For these reasons, supports incandescent, fluorescent, and LED dimmers should not be installed in undersized dimmable blubs.
In lighting configurations that use three-way switches pages 88 to 89 , buy a packaged pair of three-way dimmers designed to work together. Dimmer switches are available in several styles see photo, right. All types have wire leads instead of screw Dial-type dimmers are terminals, and they are connected to circuit wires using the most common style.
Rotating the dial changes wire connectors. Some types have a green grounding the light intensity. Until very recently, dimmers were designed to work only with incandescent lamps. When replacing incandescent lamps with CFL and LED lamps, make sure the new lamps are designed to work with older dimmers. Slide-action dimmers have illuminated faces that make the switch easy to locate in the dark. An automatic dimmer also can be operated manually.
For another example, see page 95, lower left. Be careful not of the bare wire end exposed. In new switch wiring, the white wire should not supply current to the switched device, and a separate neutral wire should be available in the switch box. This circuit wires using wire connectors. When interchangeable and can be attached to either of the two replacing a standard three-way switch with a dimmer, the circuit wires.
Test switches with a battery-operated continuity tester. The continuity tester detects any break in the metal pathway inside the switch. Replace the switch if the continuity tester shows the switch to be faulty.
Clip Probe Never use a continuity tester on wires that might carry live current. Always shut off the power and disconnect the switch before testing for continuity. Some specialty switches, such as dimmers, cannot be tested for continuity. Electronic switches can be tested for manual operation using a continuity tester, but the automatic operation of these switches cannot be tested.
A continuity tester uses battery-generated current to test Touch the tester probe to the other screw terminal. If the switch is good, the tester electrical fixtures. The tester should glow. If not, then the battery or lightbulb is dead and must be replaced.
Touch the probe to the other traveler screw terminal, Touch the tester probe to one of the traveler screw terminals, and flip the switch lever back and forth. If the switch is good, and flip the switch lever back and forth. If the switch is good, the tester will glow only when the switch lever is in the the tester should glow when the lever is in one position, but position opposite from the positive test in step 1. The test should show continuous pathways pathways for each lever position.
If not, then the switch between the two different pairs of screw terminals. Flip the is faulty and must be replaced. The arrangement of the lever to the opposite position, and repeat the test. It should pathways may differ, depending on the switch manufacturer. With the switch position. Check to see if the light fixture or appliance is lever in the ON position, attach the tester clip to the top screw working. If the pilot light does not glow even though the switch terminal on one side of the switch.
Touch the tester probe to operates the light fixture or appliance, then the pilot light is the top screw terminal on the opposite side of the switch. If defective and the unit must be replaced. Rotate arrow marker. If it does, the switch the timer dial clockwise until the ON tab passes the arrow is faulty and must be replaced. If it does not, the switch is faulty and must be replaced. Touch the tester attaching the tester clip to one screw wire leads, and touch the tester probe probe to the top screw terminal on terminal and touching the probe to the to the other lead.
Set the timer for a the opposite side. Flip the switch lever opposite side. Flip the switch lever from few minutes. If the switch is good, correctly, the tester will glow until the is working correctly, the tester will glow the tester glows when the switch lever time expires. If either half tests faulty, replace the unit. Flip the tester probe to the other lead. If the switch is working OFF position. From the basic amp, volt duplex receptacle to the burly amp, volt appliance receptacle, the many receptacles in your home do pretty much the same thing: transmit power to a load.
Learning the differences between receptacles does not take long. You need to know the amperage, voltage, and the number of devices on the circuit to select the correct receptacle.
For circuits with one receptacle, match the circuit and receptacle amperage and voltage. A duplex receptacle with a space for two plugs counts as two receptacles. Use amp receptacles on amp circuits with multiple receptacles. Use either or amp receptacles on amp circuits with multiple receptacles. Twenty- amp receptacles have the horizontal slot that forms a T with the large slot.
Though some receptacles can be wired using the push-in wire holes, this method is not recommended. If you use this method, use only amp receptacles with 14 wire and amp receptacles with 12 wire. Some receptacles provide built-in, ground-fault circuit protection, tripping the receptacle if there is a ground fault or power surge. These are easy to identify by reset and test buttons.
One last bit of information about receptacles: like switches, they vary quite a bit in quality. Paying the extra couple of dollars for a well made, durable device is worth the money. Each has a unique arrangement of slots that accepts only a certain kind of plug, and volts. For purposes of replacement, these ratings are considered identical. High-voltage receptacles are rated at , , or volts. These ratings are each is designed for a specific job. Household receptacles provide two types of When replacing a receptacle, check the voltage: normal and high.
Although voltage ratings amperage rating of the circuit at the main service have changed slightly over the years, normal panel, and buy a receptacle with the correct receptacles should be rated for , , , or amperage rating. Polarized two-slot 15 amps, volts. Three-slot 20 amps, volts. This three-slot receptacles are common in homes built grounded receptacles have two grounded receptacle features a special before Slots are different sizes to different-sized slots and a U-shaped T-shaped slot.
It is installed for use with accept polarized plugs. This new, is used primarily for window air grounded receptacle is used for clothes grounded receptacle is used for ranges. It is available as a single dryers. It provides high-voltage current The high voltage powers heating coils, unit or as half of a duplex receptacle, for heating coils and volts to run and the volts run clocks and lights. Replace the two-slot receptacle good working order. Follow these simple with a polarized two-slot receptacle or with a guidelines for evaluating or replacing GFCI receptacle.
Altering the prongs may remove the voltage or higher amperage rating. The earliest receptacles were Unpolarized receptacles have same- Surface-mounted receptacles were modifications of the screw-in light length slots. Modern plugs may not fit popular in the s and s for their bulb. This receptacle was used in the these receptacles. Never modify the ease of installation. Wiring ran behind early s. These of an unpolarized receptacle.
Ceramic duplex receptacles were Twist-lock receptacles are designed This ceramic duplex receptacle has manufactured in the s. They are to be used with plugs that are inserted a unique hourglass shape. It is rated for polarized but ungrounded, and they are and rotated.
A small tab on the end of volts but only 5 amps and would not wired for volts. The slot configuration of a high-voltage Red hot wire receptacle page will not accept a plug rated for volts. A high-voltage receptacle can be wired in one White neutral wire of two ways. Conduit may also act as a grounding conductor from the metal receptacle box back to the panel in old circuits without a grounding wire. This method is not allowed today. Screw A clothes dryer or range also may require volts terminals to run lights, timers, and clocks.
If so, a white neutral wire will be attached to the receptacle. The appliance itself will split the incoming electricity into a volt circuit and a volt circuit. Connections are made with setscrew properly wired. Hard plastic box Screw terminals Grounding wires Black hot wire Red hot wire Copper Green ground ground wire wire White hot wire coded black Screw Black hot wire terminals Conduit White neutral wire One type of receptacle rated for volts has two This surface-mounted receptacle rated for volts incoming hot wires and no neutral wire.
A grounding wire is has a hard plastic box that can be installed on concrete or pigtailed to the receptacle and to the metal receptacle box.
Surface-mounted receptacles are often found in basements and utility rooms. Homeowners with small children should add inexpensive caps or covers to guard against accidental electric shocks.
Plastic caps do not conduct electricity and are virtually impossible for small children to remove. A receptacle cover attaches directly to the receptacle and fits over plugs, preventing the cords from being removed.
Tamper-resistant receptacles are now required in all new residential installations. Standard receptacles present a real shock hazard to small children. Fortunately there are many products that make receptacles safer without making them less convenient.
Protect electronic equipment, such A recessed wall receptacle permits a Snap protective caps over sockets to as a home computer or stereo, with a plug-in clock to be hung flush against a prevent children from having access to surge protector.
The surge protector wall surface. Each half has a long neutral slot, a short hot slot, neutral strap ratings and a U-shaped grounding hole. The slots fit the wide prong, slot narrow prong, and grounding prong of a three-prong plug. This Short hot slot Wire ensures that the connection between receptacle and plug will type be polarized and grounded for safety.
Silver Grounding neutral hole Wires are attached to the receptacle at screw terminals or screw push-in fittings. A connecting tab between the screw terminals terminals Connecting tab allows a variety of different wiring configurations. Receptacles also include mounting straps for attaching to electrical boxes.
Stamps of approval from testing agencies are found on the front and back of the receptacle. LIST to make sure the receptacle meets the screw terminals strict standards of Underwriters Laboratories. The receptacle is marked with ratings for maximum volts Voltage rating and amps.
The common receptacle is marked 15A, V. AFCI receptacles have integral protection against arc The ground-fault circuit-interrupter, or GFCI, receptacle is a faults and may be required in some remodeling situations modern safety device. When it detects slight changes in current, where AFCI protection cannot be provided at the service panel. The larger picture shows a modern GFCI with an alert bulb that lights when the device is tripped. The older but more familiar style is seen in the inset photo.
Most problems associated with Everyday vibrations caused by walking across floors, or receptacles are actually caused by faulty lamps and from nearby street traffic, may cause a connection to appliances or their plugs and cords. However, the constant shake loose.
In addition, because wires heat and cool with plugging in and removal of appliance cords can wear out normal use, the ends of the wires will expand and contract the metal contacts inside a receptacle. Any receptacle that slightly. This movement also may cause the wires to come does not hold plugs firmly should be replaced. In addition, loose from the screw terminal connections. When crack with age. They must be replaced when this happens. Inadvertently installing a amp is another possible problem.
A loose connection can receptacle in replacement of a amp receptacle is a very spark called arcing , trip a circuit breaker, or cause heat common error. Repair or replace worn or damaged lamp or appliance cord. Move lamps or appliances to other circuits to prevent overloads. Tighten any loose wire connections. This eBook has more than bookmarks to speed up your access to any section of interest. Watch videos about books, reading and writing.
Expect weird, amazing, never known before facts and many more. Click here to download this free ebook. Bookworm Videos Watch videos about books, reading and writing. Please Note : This list is not the final book list. Dirty Electricity By Samuel Milham. Fundamentals of Electricity By wecc. Denny and David E. McLyman Free Download. Other Useful Links. Best Energy Engineering Books Collection.
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