Electrical Tips

Cords and Plugs
Doorbells
Lamps and Light Fixtures
Receptacles
Saving Electricity
Wall Switches
Your Electrical System
Fuses
Electrical Safety Precautions
Diagnosing Electrical Problems
Troubleshooting Electrical Problems

 

Cords and Plugs

Are the cords on your appliances looking a little ragged? Pulling and twisting can often cause the wires inside to sever and break down the insulation causing a short circuit. Replace, don't repair, any electrical cord with broken wires or brittle, worn insulation. If your cords are not detachable, you'll need to have a professional replace a faulty cord. It the cord is detachable, follow these steps to replace:

Replacing a Lamp Socket and Cord

  • To remove the socket, loosen the socket shell by pushing in where the word "PRESS" is embossed.
  • Lift off the shell and insulating sleeve.
  • Unfasten the wires from the socket terminal screws.
  • Inspect the cord insulation, if it's okay, test the socket and replace if necessary. If it's faulty, continue with these steps.
  • Replace a faulty cord by untying the knot.
  • Splice the new cord to the old by twisting the bare ends of the wires together and taping them. Pull both cords through.
  • Detach the old cord.
  • Split the new cord to 2-1/2 inches from the end.
  • Tie an Underwriter's knot by making two loops and passing the loose wire ends through the loops. Pull the knot snug.
  • Strip 1/2 to 3/4 inch of insulation from the ends of the wires.
  • Wrap one wire clockwise around each socket terminal screw and tighten the screws.
  • To reattach the socket, push the insulating sleeve over the socket and push in the shell until you hear it click into place.
  • Attach a plug to the cord.

Replacing 240-volt Appliance Cords

  • Unplug the damaged cord and unscrew the other end form the terminal screws on the appliance.
  • Be sure you get an exact replacement for the damaged cord and plug.
  • Connect the new pigtail cord to the terminal screws on the appliance.
  • If the wires in the cord and the screws on the appliance are color-coded, attach the wires to the terminal screws of the same color (black to black, white to white, red to red.)
  • If either the pigtail cord of the appliance terminal screws are not color-coded, first attach the center wire of the pigtail to the center terminal screw on the appliance.
  • Connect the remaining wires to the remaining terminal screws.
  • Plug in the new cord.

General Tips for Replacing Plugs

  • Many old-style plugs with terminal screws have a removable insulating disc covering the terminals and wires. The National Electrical Code now requires "dead-front" lugs that have a rigid insulating barrier.
  • To replace a plug, cut off the old one plus at least an inch of cord. For plugs with terminal screws, split the cord insulation to separate the wires and strip the insulation from the ends.

Replacing a Plug with Terminal Screws

  • In terminal screws the wires are attached to screws inside the plug body. To replace:
  • Unscrew and remove the new plug's insulating barrier.
  • Using a utility knife, split the end of the cord to separate the wires.
  • Push the cord through the plug body.
  • Make two loops with the wires.
  • Pass the loose ends of the wires through the loops and pull tightly to form an Underwriter's knot (this prevents strain on the terminal screws.)
  • Strip 1/2 to 3/4 inch of insulation off the wire ends being careful not to nick the wires.
  • Unscrew the terminal screws on the barrier to allow space for the wires.
  • Form loops on each wire and wrap the wires clockwise 3/4 way around the screws.
  • Tighten the screws and trim the excess wire.
  • Reattach the barrier.

Replacing Three-Pronged, Grounded Plugs

  • Unscrew the insulating barrier.
  • Push stripped wires through the plug body into the correct terminal slots.
  • Attach the wires to the terminal screws as follows: white neutral wire to silver screw, black hot wire to brass screw and green grounding wire to green terminal screw.
  • Tighten the terminal screws and reassemble the plug.

Replacing Self-Connecting Plugs

  • Push the cord (don't strip it) through the shell and into the terminal block.
  • Squeeze the prongs together to grip the cord.
  • Slide into the shell.

Replacing Female Appliance Plugs

  • Unscrew the plug shell.
  • Feed the cord through the spring guard.
  • Strip the wire ends and wrap them clockwise around the terminal screws.
  • Tighten and reassemble the plug.

Doorbells

Typical Doorbell System

The parts of a typical doorbell system are the push button, the door bell, chimes or buzzer and the transformer. The transformer allows the doorbell to operate on low voltage (6 to 24 volts.) Wired into the doorbell circuit at a junction box, it steps down the voltage from the regular 120-volt circuit. When your doorbell doesn't ring, or rings constantly, the problem may lie in one of the parts or in the wires that connect them. NOTE: To diagnose most doorbell problems, you'll need to have the power source connected. But if you're going to work on the transformer or the wires in the junction box, be sure to shut off the power to the circuit. Remember that the input side of the transformer is high voltage, 120 volts.

When the Doorbell is Silent

The first place to look is the source of power. Make sure a fuse or circuit breaker hasn't blown or tripped. Once you're certain that the 120-volt side of the transformer is getting power, shut off the power and tighten all wire connections. Turn the power back on and check the low-voltage side, following the steps below to find the source of the trouble.

Testing the Transformer

  • Use a volt-ohm meter. If the transformer is working correctly, the meter reading should match the secondary voltage (6 to 24 volts) marked on the transformer or bell.
  • Set the voltage range on the meter to 120 volts AC and measure the voltage between the two low-voltage terminals on the transformer.
  • If the meter reads significantly higher than the correct secondary voltage, the transformer is defective and should be replaced.
  • If the reading is close to the correct secondary voltage, test again by setting the voltage range on the meter to a lower value. If the new reading doesn't agree with the voltage marked on the transformer or bell, replace the transformer.

Testing the Push Button

  • Disconnect the two wires connected to the button and short them by touching their bare ends together.
  • If this makes the bell ring, the push button is defective and should be replaced.
  • If the bell doesn't ring, the problem is either in the bell or chime mechanism or in the wiring.

Testing the Bell or Chime Mechanism

  • Have a helper push the doorbell button while you listen to the bell. If it makes a buzzing or humming noise, it may be gummed up with dirt.
  • Check the mechanism and clean it as necessary using fine-grade sandpaper to remove corrosion form any contacts.
  • If the bell still hums or buzzes after cleaning, replace it.
  • If the bell doesn't make any noise at all when the button is pushed, disconnect the bell and, using new wire, hook it up directly to the transformer. If it works, inspect the old wiring. If it doesn't, replace it.

Repairing the Wiring

  • Examine the wiring for breaks or frayed insulation that may be causing the wires to short out.
  • Repair any breaks and wrap the repairs with electrician's tape.

A Constantly Ringing Doorbell

If a doorbell rings constantly, either the button is stuck or the wires going to the button are shorted together. To test follow these steps:

  • Test the button by turning off the power to the transformer.
  • Remove the button from the door frame and disconnect one of the two wires connected to it.
  • Turn the power back on. If the bell doesn't ring, the button should be replaced. If the bell rings, the problem is a short between the two wires.
  • With the power turned off, examine the wires for frayed insulation or bare wires rubbing together.
  • Use electrician's tape to wrap them where necessary.
  • If you can't find the short, replace the wires.

Lamps and Light Fixtures

Parts of a Lamp

Most incandescent lamps have a socket, switch, cord and plug. Any one of these parts may wear out and need to be replaced. To check a lamp that doesn't work, test the light bulb, plug the lamp into another receptacle to be sure the receptacle isn't at fault and check the plug and cord for wear.

NOTE: A lamp assembled with rivets instead of nuts and bolts can't be taken apart for repair, so you'll have to replace it.

CAUTION: Before working on any lamp, make sure it's unplugged.

Incandescent Light Fixtures

There are many types of incandescent light fixtures including wall and ceiling-mounted lights, from single-bulb globes to chandeliers. They are all connected directly to your home's wiring through a recessed ceiling box hidden by the fixture or a decorative canopy. Though instruction here are for repairing and replacing ceiling-mounted fixtures, you'll use the same procedures for wall-mounted styles.

When a Fixture Doesn't Work

First check the light bulb and then check the circuit and light switch. If the fixture is the problem, the cause may be in the wiring or the socket. Detach the fixture from the ceiling box and check for a loose connection. Tighten if necessary. If the fixture still doesn't work try to replace it or repair it following the instructions found below.

Replacing a Fixture

  • Shut off the power, remove the bulb and unscrew the cap nuts to free the fixture from the screws on the ceiling box.
  • Disconnect the old fixture and strip 1/2 inch off the new wires.
  • Wrap the bare ends around the circuit wires and bend over.
  • Install wire nuts.
  • Carefully push the new fixture onto the screws that hold it to the ceiling box.
  • Screw on the cap nuts to secure the fixture and replace the bulb.

Replacing a Prewired Socket

  • Turn off the power and remove the glass shade.
  • Unscrew the fixture screws to free the fixture.
  • Unscrew the wire nuts to disconnect the socket wires from the circuit wires.
  • Unclip and remove the faulty socket from the fixture.
  • Attach the new socket by pushing the wires through and splicing them to the circuit wires with wire nuts.
  • Reattach the fixture and replace the cover.

Rewiring a Chandelier Arm

  • Shut off the power to the circuit.
  • Remove the sleeve, detach the wires from the socket terminal screws and unscrew the socket.
  • Remove the cap under the fixture.
  • Temporarily tape the new socket wires to the old.
  • Detach the old wires from the main cord wires and pull the new wires thorough.
  • Screw on the new socket and connect the new wires.
  • Remove the old socket wires and attach the new ones to the main cord wires.
  • Reassemble the fixture.

 

Receptacles

How Receptacles are Wired

Most receptacles have two outlets (duplex receptacles) and are rated at 15 or 20 amps, 120 volts. One or both outlets may be electrically live at all times, or one or both may be controlled by a wall switch. The receptacle may be installed in the middle or at the end of a circuit. The wiring arrangement is different in each case.

Receptacles have three different-colored terminal screws:

  • Brass screws are hot.
  • White or silver screws are neutral.
  • Green screws are for grounding.

Receptacles may be grounding or non-grounding types. Always replace a receptacle with a grounding type unless there's no grounding wire in the box or the box isn't grounded, then you can use a non-grounding receptacle. To install a grounding receptacle to an undgrounded box, you must ground the receptacle independently. For help, consult a professional.

Because receptacles are rated for a specific amperage and voltage, be sure to replace an old one with an exact duplicate. If your wiring is aluminum, your receptacle must be designed to be used with aluminum wire (look for the letters CO/ALR.) use the terminal screws only, backwiring is not suitable for aluminum wires.

Replacing Appliance Receptacles

Appliance receptacles, rated from 15 to 50 amps, 240 volts and from 20 to 50 amps, 120/240 bolts, each require a special plug that will fit only that receptacle. Take care when replacing appliance receptacles because they have two hot wires, usually red and black, going to them. They may or may not have a separate grounding wire.

CAUTION: before beginning any work, turn off the power to the circuit. For a 240-volt circuit, you may have to remove two fuses or trip a two-handed circuit breaker.

Replacing a Grounded Receptacle

  • Shut off power to the circuit, unscrew the cover plate and remove.
  • Unscrew the receptacle from its box and carefully pull it out.
  • Note which wire is connected to which terminal screw.
  • Disconnect the wires from the screws.
  • To install the new receptacle, wrap the wires clockwise around the screws (use old receptacle as a guide.)
  • Screw the receptacle to the box and replace the cover plate.

Replacing a Backwired Receptacle

  • Shut off the power.
  • Push a small-bladed screwdriver into the slots next to the wires.
  • Pull them out.
  • To install the new receptacle push the end of the stripped black wire into the hole by the brass screws, white wire by the silver ones.

Replacing a 120/240-volt Receptacle

  • Shut off the power and remove the receptacle from its box.
  • Label the wires and screws.
  • Detach the wires.
  • Reconnect the wires to their proper screws on the new receptacle.
  • Reattach the receptacle to the box and replace the cover plate.

Professional Hint: Using Wire Nuts

For most simple repairs, you won't need to splice wires. But you may have to splice two or more copper wires to replace a damaged wall or ceiling light fixture or to make a connection in a receptacle, switch or junction box. To splice wires:

  • Strip 1 inch of insulation off the wires together clockwise.
  • Snip off 1/2 to 3/4 inch of the ends.
  • Cap the twisted wires with a wire nut, turning it clockwise to secure the connection.
  • Make sure the wire nut is the proper size for the wires.
  • CAUTION: Don't use any wire nuts to splice together a damaged extension cord. For safety, building codes allow you to splice house wires only within junction, receptacle, fixture or switch boxes. Also, be sure to turn off the power to the circuit before you make any splice.

Saving Electricity

Here are Some Tips for Saving Electricity in the Living Room:

  • Install ceiling insulation.
  • Keep curtains closed. This prevents heat loss in the winter and heat gain in the summer.
  • Close off unheated areas.
  • Don't overheat the room. Increasing the thermostat by 1 degree can increase costs by 3 percent.
  • Clean heating and air-conditioner filters regularly.
  • Dress appropriately.
  • Choose energy-efficient appliances. Compare energy rating labels before you buy.
  • Turn off appliances when you aren't using them.
  • Remove dust and fluff from the fan and reflective surfaces of heater to keep clean, efficient and safe.

Wall Switches

Types of switches

Single-pole switches control a light or receptacle from one location only and have two screws of the same color.
Three-way switches operate in pairs to control a light or receptacle from two locations. They have two screws of the same color, either brass or silver, and one (called the common terminal screw) of another color, either copper or black.
Dimmer switches are wired like single-pole switches and have either terminal screws or lead wires.

General Tips for Replacing Switches

  • Read all the information stamped on the back of the new switch. The new one should have the same amp and voltage ratings as the old.
  • If your home's wiring is aluminum, use only replacement switches marked CO/ALR. Replace unmarked switches and switches marked CU/AL with switches marked CO/ALR. Don't backwire switches to aluminum wiring, attach aluminum wires to terminal screws only.
    CAUTION: Always shut off the power to the circuit before you begin work. Use a circuit tester to make sure the circuit you're working on is dead before you touch any wires.

Replacing a Single-Pole Switch

  • Turn off the power to the circuit and remove the cover plate.
  • Unscrew the switch and pull it out carefully.
  • Unfasten the wires.
  • To attach the new switch, loop the stripped wired ends clockwise around the terminal screws on the switch.
  • Tighten the terminal screws with a screwdriver.
  • Push the switch carefully into the switch box to avoid crimping the wires.
  • Screw the switch to the box and reattach the cover plate.

Replacing a Backwired Single-Pole Switch

  • Shut off the power and unscrew the cover plate.
  • Unscrew and remove the switch from the box.
  • Push a small-bladed screwdriver into the backwire release slots on the back of the switch next to each wire and pull the wire out.
  • Push stripped wire ends (measure using the wire-stripping gauge) into the terminal on the new switch.
  • Attach the switch to the box and replace the cover plate.

Replacing a Three-Way Switch

  • Shut off the power and remove the cover plate.
  • Unscrew and pull out the switch.
  • Label the wire to the common terminal screw with tape.
  • Install the new switch, attaching the labeled wire to the common terminal screw (black or copper.)
  • Connect each remaining wire to either of the remaining screws.
  • Insert in the box and fasten.

Installing Dimmer Switch with Terminal Screws

  • Shut off the power and remove the old switch.
  • Loop the circuit wires clockwise around the terminal screws on the dimmer.
  • Insert in the box.

Installing Dimmer Switch with Lead Wires

  • Shut off the power and remove the old switch.
  • Connect the circuit wires to the dimmer's lead wires, twisting them together.
  • Screw on wire nuts and insert the dimmer in the box.

Professional Hint for Electrical Repairs: How to Strip Wire

  • Use a utility knife or penknife to strip insulation off the ends of the wire.
  • Use the knife blade to cut through the insulation all the way around, then pull the insulation off the wire.
  • Be careful not to nick the wire when you cut, a nicked wire breaks more easily, especially if the nick is where you bend the wire to form a loop for a connection to a terminal screw.
  • If you do nick the wire, it's best to cut the wire back to the nick and start stripping again.
  • For the best results, purchase a wire stripper at your local hardware store.

Fuses

What are Fuses?

Fuses have a thick metal strip through which current passes into a circuit. If too much current starts to flow, the metal melts and cuts off the current. Fuses may be one of several types:

  • Plug and Type S fuses have a metal strip (visible through a window) that melts when there's an overload.
  • Time-delay fuses have a spring-loaded strip that allows temporary overloads.
  • Cartridge fuses show no sign of overload. They must be tested to reveal whether they've blown.

Fuse Safety Tips

  • When a fuse blows, always replace it with one of the same type and amperage rating. Never replace it with one rated higher.
  • When you need to change a blown fuse, shut off all power before touching the fuse and be sure you're standing on dry ground.

Electrical Safety Precautions

Working with electricity can be dangerous unless you adhere strictly to certain rules. CAUTION: NEVER WORK ON ANY LIVE CIRCUIT, FIXTURE, RECEPTACLE OR SWITCH. Your life may depend on it. Safety rules you should follow whenever you're working with electricity include:

  • Always shut off power at the main disconnect before changing a fuse.
  • Always shut off power to the circuit before repairing or replacing a switch, receptacle, or fixture.
  • Always tape over the main switch, empty fuse socket, or circuit breaker, empty fuse socket or circuit breaker when you're working. Leave a note there so no one will accidentally turn on the electricity. Keep any fuses you've removed in your pocket.
  • Always check that the circuit is actually dead before you begin working on it. Use a circuit tested or voltammeter.
  • Always unplug any appliance or lamp before repairing it.

Diagnosing Electrical Problems

Typically, you discover you have an electrical problem when you turn on a lamp or appliance and it won't work. When that happens, the source of the problem may be the device itself, faulty wiring connections, an overloaded or a short circuit.


Overloaded circuit

A circuit becomes overloaded when there are more lamps and appliances on it than it can safely handle. When all the lamps and appliances are turned on, the wiring overheats and the fuse blows or the circuit breaker trips.


Short circuit

A short circuit occurs when a bare hot wire touches a bare neutral wire or a bare grounded wire (or some other ground). The flow of extra current blows a fuse or trips a circuit breaker.


Helpful Diagnostic Hint

Plug fuses provide a clue to what made them blow

  • An overload melts the bridge.
  • A short circuit blackens the glass.

 
 
 
 
©Copyright Burel and Associates, LLC 2007