Finish Wiring

Up to this point you have accomplished quite a lot. You have mapped out your circuits, installed the switch and receptacle boxes in the appropriate locations, run the correct cables into the boxes, and installed the service panel. After these installations are inspected and approved, and the walls and ceilings are finished, you are ready to make the final connections and turn on your electrical service. This hook-up step, which is called finish wiring, involves three specific stages. First you connect the cable in each box to the appropriate receptacles, switches, and light fixtures. Next you make the hard-wired connections at all the fixed appliances and equipment. Finally you make the branch-circuit connections in the service panel. Installing cover plates at the switches and receptacles completes the job. Finish wiring is by no means the most complicated part of wiring a house, but it still requires care and attention to detail.

There can be more to finish wiring than attaching conduits to receptacles or switches. The kitchen or laundry room can require an array of hookups.

GENERAL INSTALLATION TIPS

All finish work must be done with care. The wires must be connected to the fixture properly, of course, and the fixture itself must be plumb and level and fit flush against the wall or ceiling with no gaps showing.

Installing Receptacles

Receptacles should be held plumb while you tighten their mounting screws. After tightening, step back and check your work. If it's necessary to adjust, or “tune,” it, hold a screwdriver tip against the top or bottom of the device strap near the mounting screw and gently tap the screwdriver with pliers until the device is plumb.

If the electrical boxes were installed properly, the finish wall and ceiling materials should be flush with the front edges of the boxes. When they are, installing the devices is easy, and their finished appearance looks smooth and professional because the plate fits the device with no unsightly gaps around the edges. A box that extends only slightly beyond the wall usually isn’t a real problem because the shape and flexibility of the plate will ad just for it. If the wall surface extends beyond the edge of the electrical box, the plaster ears on the device strap will keep it from being drawn into the wall when it's attached to the box. Occasionally, especially in existing plaster walls, the opening around the box is too large for the plaster ears to be effective. One remedy for this is to space the device away from the box and flush with the wall surface with washers or nuts that the mounting screws pass through.

Installing 120-Volt Receptacles

When wiring a 120-volt duplex receptacle, connect the white wire to the silver-colored screw, the black (or possibly red) wire to the brass-colored screw, and the green (or bare) wire to the green screw. All the connections are made by first strip ping 1 inch of insulation from the ends of the wire; then use needle nose pliers to bend the end of the wire into a loop, and slip the loop over the body of the screw in such a way that tightening the screw will tend to close the loop. Close the loop with the pliers and tighten the screw. Note that back-wired receptacles don’t require this wire looping. Instead, strip the wire to the length indicated by the strip gauge for the device. Then, depending on the type of back-wiring, either simply push the stripped wires into their appropriate holes, or push the wires into the proper openings and tighten the terminal screws. Tug on each wire to check for a tight connection.

If you should need to re move the wires from a back- wired push terminal, there is a release slot for this purpose. You can simply insert a small screwdriver into this slot to re lease the wire.

If you are installing the two receptacles side by side, use the second set of terminal screws on the first receptacle to re-feed the second receptacle. Never use the second set of screws to feed additional receptacles in other boxes. Instead, use pig- tails connected to the incoming and outgoing cables to connect to the receptacle. Some local codes may require pigtail connections even for side-by-side receptacles.

Installing 240-Volt Receptacles

Some 240-volt equipment is al ways hard-wired to its source of power. Two examples are water heaters and central air- conditioning equipment. There is no reason to cord-connect these major appliances because they don’t have to be moved in order to be serviced. On the other hand, ranges, cooktops, and wall-mounted ovens can be hard-wired, but it usually makes more sense to use cords and plugs with them for ease of disconnecting when they re quire servicing. Clothes dryers are cord-connected for the same reason.

82 Reading a Receptacle: Break-off tab; Voltage and amperage ratings; Acceptable wire; Tester’s approval

83 Wiring Receptacles:

Do not install in a switch loop like this

Here the switch controls both light and outlet

Here it controls only the light—the outlet is always hot

Middle-of-the-run

Power source

End-of-the-run

Switch-Receptacle Combination

To switch

Color of Wire

Neutral wire – White - Silver or white

Hot wire; Black - Brass

Hot wire – Red; Brass

Grounding wire: Green; Bare wire; Electrical box ground

Note: A white wire used as a hot wire such as when using Type NM cable for a switch loop must be made black at both ends

===

A Note on Wire Color Coding

The neutral wire is white and always connects directly to the light fixture and never to the switch. Otherwise, the light could still work but every time the switch was turned on there would be a dangerous potential for shock at the light fixture because the neutral wire could no longer provide a safe unbroken path back to the source.

Switches should always be connected to the hot wire not the neutral. In most cases the hot wire is either black or red. But if you are using non-metal hc cable for the switch loop between the switch and a light fixture fed directly by the source one of the wires in that cable will be white even though it will function as a hot conductor This hot conductor is called a white made black wire and it should be marked at both ends with black electrical tape black paint or other black marking to indicate its status as a hot conductor This wire and the true black wire are interchangeable. At one end of the cable both wires are connected to the switch at the other end one wire is connected to the light fixture at the brass colored screw or black pigtail wire and the other wire is connected to the hot conductor from the source with a wire nut or other approved electrical splice.

= = =

Color Coding of Wires and Terminal Screws for Switches, Receptacles, and Light Fixtures

Function of Wire; Color of wire and Terminal Screw

Neutral wire; Hot wire; White; Black; Red; Green; Bare wire; Silver or white; Brass; Green; Electrical box ground

= = =

84 Connecting Wires to Switches

1. Push in the push-in terminal

2. On the gauge on switch, measure length of exposed wire

3. Push exposed wire into opening in terminal

Wiring for a 240-volt receptacle begins at the service panel and terminates in an electrical box located on the wall at the appliance location. The run can be spliced, inside a junction box, but must not have any branches or other receptacles on it. The wire must be sized for the amperage of the appliance (e.g., No. 10 wire and a 30-amp circuit breaker for a 30- amp dryer; No. 6 wire and a 50-amp breaker for a 50-amp range). Not all 240-volt receptacles are identical. Choose a receptacle which is sized for the amperage of the appliance and wire. It must also match the plug configuration on the appliance cord.

Install the receptacle by attaching the feed wires of the cable to the screw terminals on the back of the receptacle: Al ways connect the hot wires to the brass terminals, and , de pending on the equipment, the green, white, or bare wire to the remaining terminal. Note that wiring for some 240-volt appliances, such as water heaters, does not require a separate ground wire insofar as the neutral wire serves that function.

Installing Switched Receptacles

The NEC requirement for wall- switch controlled lighting in all of the habitable rooms in the house is usually met by switching the top half of one receptacle in each of the bedrooms and the living room. The other half of the receptacle is powered all the time. When this is done, the receptacle halves are electrically isolated from one another by twisting out the break-off tab that ties the two brass-colored screws together, and connecting the hot wire to the bottom brass- colored screw, and the wire coming from the switch to the top one. The neutral wire connects to the silver-colored screw and serves both halves of the receptacle.

Combination switches and receptacles look essentially like ordinary duplex receptacles except that the top half of the device contains a toggle switch that operates horizontally. They provide a means of switching a circuit and having 120-volt power available at a single one-gang switch box. Some of these devices are furnished with a built-in neon glow lamp that indicates when the switch is on. A variation of this combination device pro vides a three-way switch with a grounding receptacle.

85 Wiring a Single-Pole Switch: Source through Switch: To power source; Source Through fixture; White wire painted black if required; Switch loop; To power source; White wire painted black if required

86 Installing or Replacing a Three-way Switch: Power Coming from Source; Tape marking common wire

Installing GFCIs

GFCI duplex receptacles are found in nearly all new houses. GFCI circuit breakers combined with ordinary receptacles pro vide the same protection; but GFCI receptacles have the added convenience of the reset and test capabilities available at the receptacle rather than at the service panel. It’s common practice in kitchen wiring to run one of the two required small-appliance circuits directly to a GFCI located near the sink, and then to feed any other receptacles in the kitchen that require ground-fault protection from that GFCI.

GFCIs are physically larger than ordinary duplex receptacles, which means they can’t always directly replace an ordinary receptacle. They’ll fit in most switch boxes, provided the box isn’t loaded with wires, but they don’t always fit in houses that are wired with square boxes and mud rings. They can be used to advantage as replacements for ordinary receptacles in older houses with ungrounded branch- circuit wiring. GFCIs offer excellent shock protection even when there’s not a grounding conductor connected to them.

Installing Switches

Most houses will use a variety of switches that may include two-way, three-way, four-way, and dimmers. The wiring is slightly different for each type.

Two-way Switches

The most common, and easiest to understand, switch is the ordinary on-off single-pole switch known as a two-way. It has two screws to which the circuit conductors are connected, and it makes no difference which conductor is connected to which screw. The single-pole switch isn’t used in combination with other switches, and like most switches sold today it has a ground terminal screw on its strap.

Three-way Switches

Switches used in pairs to control lighting from two different points are called three-way switches. They’re characterized by three circuit-conductor screws, two brass-colored and one bronze-colored, and the absence of on and off labels on the switch handle. The bronze- colored screw is connected internally to the shunt, or common, connection. Moving the switch up connects the common with one of the brass-colored screws, moving it down connects it to the other.

Three-way switches can be connected in a number of ways. The simplest system involves connecting the “hot” lead to the shunt of one switch (the dark or bronze-colored screw marked as “common”) and connecting a pair of wires between the brass-colored terminals of one switch and those of the second switch. These wires are called travelers. Finally, the shunt terminal of the second switch is connected to the light that’s being con trolled, along with, of course, the neutral wire.

Old switch; Tape marking common wire; Power Coming from Fixture

85 Wiring Switches and Receptacles: Source through Switch

Another common three-way arrangement employs switch loops. Often, branch-circuit wiring is run directly to a ceiling box where a light is to be installed. In this case, three wires are run to each switch location. When cable is used, you connect the black wire to the bronze-colored screws on both switches, and the red and white wires to the brass- colored screws. Back at the ceiling box, splice the three- conductor cables red to red, and white to white. Connect the hot wire to either black wire, and the other black wire to the brass-colored screw or colored wire at the fixture; it makes no difference which goes where. Then connect the neutral wire to the fixture.

Four-way Switches

For additional points of lighting control between pairs of three-way switches, four-way switches are available. Any number of four-ways can be used, but they must be in stalled between a pair of three- way switches. Four-way switches can be identified by their terminal screws and the absence of on and off on their operating handles.

To power source; terminals; White wire; painted black

86 Installing or Replacing a Three-way Switch: Power Coming from Source; Power Coming from Fixture

White wire painted black; Tab removed

87 Wiring Switches and Receptacles: 4 wires in conduit; Four-way Switch; 3-way switch; 3 wires; Split-Circuit Receptacle; 2-wire cable with ground

Dimmers

Dimmers are available in both single-pole and three-way forms. The dimmers that are commonly available are exclusively for incandescent lights, and should be used only to control fixed lighting, not the switched receptacles found in most homes. Fluorescent-lamp dimming requires a special dimming ballast and an auxiliary control that’s matched to the ballast. These can be obtained from lighting wholesalers and seldom elsewhere.

When installing a dimmer, it’s doubly essential that before you begin you turn off the power to the circuit on which you will be working. As al ways, you are ensuring your own safety, but you are also protecting the dimmer, which would probably be damaged or destroyed if it were installed while the power was on. Re placing a single-pole switch with a dimmer is simply a wire-for-wire changeover. A three-way dimmer can replace one, but not both, of the three-way switches in a multiple switching arrangement.

Basic dimmers have either a knob that’s turned clockwise to turn the lights on, or a knob that's pushed for on and pushed again for off; once on, the knobs of both types are rotated to adjust the level of lighting. A move up from this is the toggle control, which looks like an ordinary toggle switch and varies the lighting level as it’s moved up and down. Slide dimmers are similar to the toggle type in operation, but the sliding operator doesn’t extend outward. At the top of the dimmer line is the touch-control switch. This switch has a rectangular plate that fits almost flush to the wall. Touching the plate briefly and releasing turns the lights fully on; when the plate is touched a second time and held, the light level slowly varies until the plate is released. When the plate is touched and released again, the lights are turned off.

If you are counting on dimmers to save electricity, you need to investigate further be fore purchasing dimming mechanisms. Some will indeed reduce electrical use as lights are dimmed, but others consume maximum electricity regardless of the lighting level by using a rheostat device which burns off any current not used by the light.

Replacing an Existing Switch

Always turn off the power when you replace a switch. Re placing a single-pole switch involves removing the two circuit wires plus the ground wire, if one is present, and re connecting them to the new switch. Either circuit wire can go to either switch terminal because the switch will work correctly regardless of which goes where. Note that three- and four-way switches require greater care when replacing. It’s best to make a diagram showing terminal and wire colors; you may need it to get the lights working properly again. If there are two or more wires of the same color at the switch, identify them with different numbers of narrow bands of electrical tape or some other handy means. Look at the screw colors carefully. Some are bronze-colored and some are brass-colored. After connecting, fold the wires carefully back into the box and fit the switch into the box before tightening the mounting screws to avoid damaging the wire.

88 Installing a Dimmer Switch; Two-way Dimmer

Push-in connection; Screw terminal

Three-way Dimmer

Mark common wire with tape their four circuit-conductor terminal neutral supply wire.

INSTALLING LIGHT FIXTURES

Surface-Mounted Fixtures

Most surface-mounted fixtures, such as those on walls and ceilings, mount on a strap or bracket that's first connected to the lighting outlet box. The straps are designed to fit the mounting dimensions of the standard outlet-box device, and then provide tapped mounting holes for attaching the fixture to it. Any combustible ceiling or wall material that’s exposed between the canopy edge of the fixture and the edge of the out let box must be covered with noncombustible material. The manufacturer usually provides a pad of fiberglass material about the size and shape of the canopy for this purpose.

Pendant-mounting refers to ceiling fixtures that are chain or stem-mounted beneath their canopies. When installing any ceiling fixture, the job goes much more easily with a helper to hold the fixture in position while you do the wiring.

A typical recessed light assembly includes a lamp housing and a wiring connection box mounted on a frame that attaches to the house framing with a pair of built-in, adjust able bar hangers. In addition, the assembly includes a piece of trim that will give the fixture a finished look after the installation is complete. The assembly, or frame, is installed so that its lamp opening bottom will be flush with the finished ceiling. Branch-circuit wiring is run directly to the wiring connection box of the fixture. Lamping the fixture and in stalling the trim after the ceiling is finished completes the installation. The wiring in the wiring connection box can be accessed after installation by re moving three or four screws that hold the housing to the frame, then pulling the housing down and out of the frame.

Some recessed fixtures are designed for use where they’ll be in direct contact with thermal insulation. Others are for use in uninsulated ceilings or in ceilings where the insulation will be kept at least 3 inches from the fixture.

Standard fixtures are about 7½ inches deep, and special 5 1/2-inch fixtures are made for installation in 2 by 6 ceilings. Certain universal models have housings that can be adjusted from 5½ to 7½ inches in depth. Still others are available for installation in sloped ceilings. Many manufacturers make recessed fixtures for the remodel market. These fixtures can be completely installed from be low the finished ceiling.

Lighting fixtures in unfinished basements, attics, and garages are usually mounted directly onto surface-mounted outlet boxes. The porcelain lamp holders commonly found in these locations connect directly to the box with 8-32 screws. Fluorescent fixtures are also used in these areas, usually suspended on fixture chains, and cord- and plug-connected to their source of power.

Track Lighting

Track lighting provides an extraordinary degree of lighting flexibility. It allows light to be easily directed exactly where it’s needed. The track used is an extruded aluminum channel that holds two electrical conductors, one in each side of the extrusion, that are mounted in continuous insulated supports. The inside surfaces of the conductors are bare. When a lamp fixture is snapped into the track, two terminals on the fixture contact the track conductors, and power is supplied to the fixture. Fixtures are also connected to ground through the track.

Track is usually available in 2-, 4-, and 8-foot lengths, and it can be cut to any desired length with a hacksaw. Sections are fastened together with special connectors when longer runs are needed. End caps provided by the manufacturer give the track a finished look. Track lighting is most commonly surface-mounted, but may also be pendant-mounted, and is often connected to branch- circuit wiring with a floating- feed device. All that’s necessary for floating feed is that the track cross a lighting outlet box. At this point, a connector that's similar to the connectors on the individual fixtures is wired to the supply conductors and then snapped into the track in much the same way a fixture is. A canopy is installed that covers both the outlet box and the short portion of track that crosses the box. The track conductors become energized when power to the outlet box is turned on. Manufacturers of track lighting have engineered their systems so that proper electrical polarity is always maintained. The polarity lines inside the channel must be aligned when sections of track are installed, and the fixtures will snap into the track in only one way, which assures that proper polarity will be maintained at the lamp holder.

Fixtures are available in a number of styles for general illumination, accent lighting, and wall washing. Fixtures from different manufacturers aren't interchangeable.

Proper polarity must be observed when wiring light fixtures. Also, properly ground the fixture. It is standard practice, based on an NEC requirement, for manufacturers to connect the screw shells of their fixture lamp holders to the silver-colored screw, or white wire, which will be connected to the grounded

Recessed Lighting Utility. Area Lighting

Installing Ceiling Fixtures

Fixture cable Box cover

Hanger bracket

Surface Fixture

Nipple nut

Hickey

Pendant Fixture; Locknut

Chain holds fixture

Ceiling

Note: Ceiling fixtures are attached with either a threaded stud and locknut, or screws

Track System

Recessed Fixture

Integral

Light housing junction box Ceiling ; Neutral wires; Ground wire screwed to box; Hot wires; cable; Toggle bolts or screws; Reflector trim

OTHER INSTALLATIONS

Ceiling Fans

Many owners of older homes have simply replaced an existing ceiling fixture with a fan and have had no trouble at all. However, this can't be done in newer homes with their nonmetallic outlet boxes. By it self, this type of box isn’t able to properly support the weight of a ceiling fan. You must in stall an approved box before mounting the fan.

One approved box is simply a modified 4-inch by 1½-inch octagon box which has two holes drilled through its back, each directly above a cover- mounting screw hole. Long 8- 32 screws are passed through the holes and are threaded as far as they will go through the tapped holes of the box, leaving two studs to which the fan mounting bracket will be attached.

The box is mounted on the face of a 2 by 4 block that’s nailed between two ceiling joists, at a height that puts the front of the box flush with the finished ceiling. Four screws hold the box to the block. The mounting bracket of the fan is slipped onto the studs and is secured in place with stop nuts. The fan is then mounted on its bracket according to the manufacturer’s instructions.

There are kits available for mounting an approved ceiling- fan box in existing homes where there isn’t access above the ceiling. Installation involves cutting a 4-inch round hole in the ceiling, and then passing an adjustable-length hanger through the hole and driving both ends of it into the ceiling joists. The box is then attached to the hanger.

Control for the fan can be a simple on-off switch or a speed control. An additional switch should be used when a light kit is installed on the fan. Some more expensive fans use a smart control that regulates the speed and direction of the fan as well as the lights, all from one wall-switch location.

Smoke Detectors

Every home must have at least one smoke alarm installed. A mix of 120-volt and 9-volt battery-operated units is best

Note: There are 2 options for installing the support strap in a ceiling box: using a locknut or using wire nuts. Choose 1 option.

A variety of other options are available, but the two most commonly installed are ceiling fans and hard-wired smoke detectors. Ceiling fans require an approved mounting means. Smoke detectors should be wired into a frequently used branch circuit so that any loss of power will be quickly detected.

Hard-Wiring a Smoke Alarm

Ceiling box nut; Strap; Smoke detector; Test button

because there’s little chance that the battery and the electric power will fail at the same time. Some manufacturers make 120-volt units that are backed up with a 9-volt battery. Smoke detectors should be installed near the furnace, in or near the kitchen, and in hall ways outside of bedrooms.

Two basic sensing systems are used in detectors. Photo electric systems are especially responsive to smoldering fires; smoke detectors of this type are best used in kitchen and bed room areas. Dual ionization systems respond effectively to rapidly developing fires. This type is effective in furnace rooms and storage areas.

Front-door striker; Padded screw; Low-note chime

Note: Chimes shown with decorative cover removed: Bell; Button; Transformer; Motion Sensor; lights

These special lights are generally used for outdoor installations. Whenever motion is detected within their range, the light automatically switches on. It stays lit for a set period of time and , if there is no further activity, turns itself off. Some systems can also discriminate by size, activated by a large dog, for example, but not a squirrel.

Motion-sensor lights are no more difficult to install than an ordinary light fixture. In fact, they generally follow the same procedures. Some are as straightforward as changing a light bulb.

Installing a Doorbell

Junction box; The Transformer; Low-voltage terminals; Wire to bell or chimes; Wires connected to push button; Line-voltage house current; Transformer; Terminals; Chimes; Electromagnets; Low-voltage wires Wiring a Three-Wire Appliance Receptacle; Electric; Metal conduit receptacle

Neutral conductor

Connecting a New Wire to an Existing Circuit Note: Some areas may require pigtails. Check your local codes.

End-of-the-run receptacle; Middle-of-the-run receptacle; Middle-of-the-run switch

To make middle-of-the-run circuit extensions, expand a box either by adding a box extender or by ganging

Wiring a Multiwire Circuit

From source; Second receptacle is wired with red wires; Third receptacle is wired with black wires

OUTDOOR FINISH WIRING

Although boxes for outdoor installations must be of weatherproof design, except those in stalled in exterior building walls, standard switches and receptacles can be used for the finish wiring and are installed using the same techniques as indoor installations. The covers, however, are different. Covers for duplex receptacles have either a pair of spring- loaded gasketed doors or a single door that covers both receptacles. GFCI covers have a single door. There are two options for covering switches. One cover has a single door that covers an ordinary toggle switch handle. The other type has no door. It has an auxiliary handle that's accessible at all times, but is electrically insulated from the switch and toggle that it conceals and protects. Install it by slipping a fork- shaped device, included with the cover, over the switch toggle and connect it to a shaft inside the cover. Then screw the cover in place.

Light fixtures are essentially the same as indoor lights, although they have gaskets or other weatherproof devices to ensure a tight seal against the box. Some have internal junction boxes built into them and are attached directly to conduit, without the need for a separate box.

Great effort is made to make outdoor outlet boxes weather- tight. Even so, in spite of gaskets and sealing methods, water from driven rain some times finds its way into these enclosures. Because this might happen, it’s important to pro vide a way for the water to drain easily so it doesn’t accumulate and cause damage. The simplest, most effective way to do this is to drill a 1 weep hole in the bottom of the enclosure. This guarantees good drainage.

Box-sealing kits are available for boxes used outdoors. If you choose not to use such a kit when finishing, use a small amount of ordinary automotive grease on all threaded mechanical connections, and apply a light coat to all gasket surfaces. This makes it much easier to loosen device screws and box plugs in the future. Smear a light coat of petroleum jelly on all lamp threads before installing them. Do this and you should never have a problem removing a burned-out bulb.

Electrical connections in outdoor wiring are made in the same way as when wiring indoors. However some areas of outdoor finish wiring require special attention.

Installing Fixtures Additional

Weatherproofing

Installing a Back-to-back Box Outside

Troubleshooting and Common Problems

Two simple tools can help you locate problems in electrical systems and equipment—the continuity tester and the neon test lamp. Either can be purchased for Just a few dollars Without these tools, trouble shooting can become little more than a guessing game.

A very common continuity tester has a cylindrical body that holds two small batteries and a small lamp. A one-inch-long probe is attached to one end of the body, and a 3-foot-long test lead with an alligator clip on the outer end is attached to the other end. The light turns on when the alligator clip makes contact with the probe because this contact closes the circuit of the tester.

To check a questionable switch, first turn off the power. Then clip the test lead to one of the switch terminals, hold the probe to the other, and turn on the switch. If the switch is good, it will complete the tester circuit and the lamp will glow. A word of caution: Don’t use a continuity tester on energized circuits. Besides the risk of shock to you, there’s a risk to the tester. If the switch in the example above was in an energized circuit—a circuit complete with a properly operating light fixture—and the tester was applied to the switch when it was in the off position, 120 volts would be applied to the tester, and it would be dam aged beyond repair.

Continuity testers can test the continuity only of circuits and devices that offer low resistance to the flow of electricity. This isn’t a serious limitation because many electrical problems involve only switches and wiring interconnections. Successful use of the tester simply requires that it be applied systematically from point to point until the “open” is located. Testing other de vices such as motor windings, solenoid valve coils, and heating elements is done with an ohmmeter, or the ohmmeter function of a multimeter.

When using a neon test lamp to check for voltage at a 120-volt receptacle, place one test lead in each of the parallel slots of the receptacle, and the lamp will glow if voltage is present. Remove the test lead from the longer of the two slots, touch the lead, and the lamp will again light. The lamp will also glow if you insert the open lead into the U- shaped slot of the receptacle, or if it contacts the metal screw that holds the wall plate in place. In fact, in each case where the test lead had been withdrawn from the larger slot, the slot to which the branch-circuit neutral is connected, the lamp would have glowed even if the neutral wire wasn’t present at all. This illustrates the importance of testing at slots or terminals that connect to the current- carrying conductors of the branch circuit whenever possible.

Neon test lamps have many additional uses. Proper polarity at a 120-volt receptacle can be checked by making certain that voltage to ground is present only at the smaller of the two parallel slots. To test this, hold one of the leads while you insert the other first into one slot, then into the other. if the polarity is all right, place one lead back into the small slot and the other into the U-shaped slot; if the neon glows, the grounding at the receptacle is okay, too. Most test lamps will operate at voltages from 60 to 250 volts, so they can also be used to check your 240-volt circuits.

Replacing a Ballast Installing a new ballast in a fluorescent fixture is a common project. First make certain the ballast is the problem by checking the circuit for power, changing the lamps, and the starter if the fixture uses one. If this doesn’t restore operation, disconnect the power to the fixture and immediately open it up to expose the ballast. Carefully touch the ballast to see if it's warm. If it isn’t, it probably needs to be replaced.

Begin by removing the existing wiring to the lamp holder and power source at a point close to the ballast.

Remove the defective ballast — usually only two screws hold it in place—and install the new unit. Tighten the mounting screws or nuts, so that the bal last is held very firmly to the fixture. Be certain that the black and white wires on the ballast are toward the same end of the fixture as those of the original ballast were.

The wires on replacement ballasts are seldom long enough to reach the lamp holders, so it’s common practice to splice the old and new wiring with wire nuts. It’s not always possible to connect the wires to the lamp holders color for color because over the years color standards have changed. Also, any high temperature wire must be replaced with the same kind. To avoid problems, follow the wiring diagram shown on the ballast nameplate. Extend each of the new wires toward its destination, then fold the final 4 inches of each wire back to ward the ballast, Extend the old wires toward the ballast and cut off each at a point next to the end of the new wire to which it will be connected. Strip 1/2 inch of insulation from the ends of the wires and connect old to new using wire nuts. Bundle the groups of wires on each side of the bal last and band each group together with two or three wraps of electrical tape.

Types of Plugs: Screw ; Terminal Plug

Fluorescent Fixture; Wiring; Rapid Start

Power cable; Remove insulating cap; Tie an underwriter’s knot

Polarized Plug

Connect wires to terminals

Three-Prong Plug

Push in one end to remove

Black hot wire to narrower prong

Ground

Self-Connecting Plugs

Insert cord and push lever down

Replaceable Start or Preheat

Insert cord under top and slide top closed

Insert cord through case into prongs and squeeze prongs parallel

Starter: turn counterclockwise to remove

Lump Components

Outer shell Insulating sleeve

Socket; Socket cap

Underwriter’s knot; Final

In a lamp with 2 or more sockets, each socket is wired separately, and the wires are connected to the main cord with the wire nuts at the top of the threaded tube.

Rewiring an Incandescent Lump

Lamps with incandescent bulbs are all quite similar, whether they are large floor lamps or small table models. A lamp has only a few basic parts that can cause a malfunction: the bulb, the socket, the switch, the cord, or the plug. Understanding how a lamp is put together not only allows you to make any necessary repairs, but also to make your own lamps from old bottles, pieces of driftwood, or anything that strikes your fancy. All the parts to put a lamp together from scratch can be found in kit form in hardware and electrical stores.

Taking Apart a Lamp

1. Unplug the lamp and remove the bulb.

2. Remove the shade. It may be necessary to unscrew the finial at the top of the harp to free the shade. If your lamp has a 2-piece harp, slide the 2 metal sleeves up at the base of the harp, squeeze the harp at the base. and lift it out.

3. The socket consists of 4 pieces: the outer shell, the insulating sleeve, the socket with switch and terminal screws, and the socket cap. To remove the shell, press in with your thumb where the shell is stamped “press” and lift up. If the shell will not come off, pry it up with a screwdriver. Remove the cardboard insulating sleeve. Loosen the 2 terminal screws on the socket and remove the wires. Lift the socket out of the cap.

4. To remove the cap, first loosen the setscrew at the base of the cap. Unscrew the cap from the threaded nipple. If there is no setscrew and the cap does not readily unscrew, give it a forceful turn.

5. If you must remove the cord from the lamp pipe, tape the new cord to the old and pull it through as you remove the old cord.

6. Part the new cord about 2” back and tie an Underwriter’s knot at the top, as illustrated.

7. Strip off ½” to 3/4” of insulation at the end of the wire, twist the wire clockwise, and wrap it clockwise around the terminal screws. Tighten the screws. Reassemble the lamp.

In a lamp with 1-inch socket, the cord goes into the base, winds up through the threaded tube, and connects directly to the socket terminals.