Guide to Electrical Repairs for Your Home

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Home Improvement

Are you attempting to repair something in your home yourself? Spiderstock / Getty Images

Although your home’s plumbing and electrical systems may seem very different, there are actually many similarities. Just like water enters your home through a pipe under pressure, electricity enters your home through wires under pressure, which is measured in volts. Similarly, when you turn on a tap, the water flows at a certain rate in gallons per minute, and when you turn on an electrical device, the electricity flows at a certain rate in amps.


When replacing a receptacle, ensure that the replacement matches the one that you are removing. If you have a grounded type, you must purchase a receptacle with a ground terminal screw and slots for three-prong grounded plugs.

Unlike water, electricity is intended to do work, which is measured in watts. Since household electrical consumption can be relatively high, the unit of measure most often used is the kilowatt, which is equal to 1,000 watts. The total amount of electrical energy you use in any period is measured in terms of kilowatt-hours (kwh).

The electric meter is the device that records how much electricity you use. It tells the power company how much electricity they need to charge you for. There are two types of electric meters in general use. The first type displays a row of small dials with individual indicators on its face. Each meter dial registers the kilowatt-hours of electrical energy. For example, if you leave a 100-watt bulb burning for 10 hours, the meter will register 1 kilowatt-hour (10×100 = 1,000 watt-hours, or 1 kwh). Each dial registers a certain number of kilowatt-hours of electrical energy. On most meter faces, the far right dial counts individual kilowatt-hours from 1 to 10, the next one counts from 10 to 100 kilowatt-hours, the third dial counts up to 1,000, the fourth up to 10,000, and the dial at the far left counts kilowatt-hours up to 100,000. If the arrow on a dial is between two numbers, the lower number should always be read.

The article discusses the two types of electric meters used in households and the three main lines that supply power to homes. The first type of electric meter has individual dials, while the second type has numerals in slots on the meter face. The meter is read from left to right, and the numbers indicate total electrical consumption. Some meters also use a multiplying factor to get the true figure in kilowatt-hours. Understanding how to read the meter helps verify the charges on the electric bill and monitor energy consumption at home.

The three main lines supply 110-120/220-240 volts AC to the home. The exact voltage varies based on external factors. The three-wire system provides 110-120-volt power for lighting, receptacles, and small appliances, as well as 220-240-volt power for air conditioning, electric range, clothes dryer, water heater, and electric heating.

Electricity enters the home through the power company’s service equipment, which is a disconnect device mounted in an approved enclosure. The disconnect device disconnects the service from the interior wiring system. It is usually a set of pull-out fuses, a circuit breaker, or a large switch. The main disconnects are mostly located inside the house in a large enclosure that also contains the fuses or circuit breakers, which handle the distribution of power throughout the building.

The three wires from the meter enter the main entrance panel, which contains the heavily insulated black and red lines attached to the tops of a parallel pair of exposed heavy copper bars, called buses, at the center of the box. These two lines are the “live,” or “hot,” wires. The third wire, generally bare, is the “neutral,” attached to a separate grounding bar, or bus, that is a silver-color strip in the main box. In most homes, this ground bus is connected to the ground by a heavy solid copper wire clamped to a cold water pipe or an underground bar or plate.

The article also discusses overload protection, stating that circuit breakers are switches that automatically trip open to interrupt the flow of electrical current when it overloads the circuit. Power is distributed through various electrical circuits that start in the main entrance panel, and the neutral wire is always connected to the ground bus and should never pass through a fuse or circuit breaker.

Fuses and circuit breakers are important safety devices that are built into electrical systems. Without these devices, overloading a circuit could cause the cable carrying the power to become extremely hot, short circuit, and even start a fire. To prevent this from happening, circuit breakers and fuses are designed to trip or blow, stopping the flow of current to the overloaded cable. It’s important to note that a blown fuse or a tripped circuit breaker is not faulty, but rather an indication that there is trouble somewhere in the circuit. To fix the issue, you need to locate and eliminate the cause of the problem before replacing a blown fuse or resetting a tripped circuit breaker.

It’s crucial to never try to bypass the built-in safety system by replacing a fuse with one of a higher current-carrying capacity. The fuse or circuit breaker capacity should be equal to or less than the current-carrying capacity of the conductors. Additionally, circuit breakers do not blow like fuses, but instead, they are switches that automatically trip open to interrupt the flow of electrical current when it overloads the circuit. To reset a tripped breaker, turn it fully off and then back on.

There are two types of circuits: feeder and branch. Feeder circuits use thicker cables that travel from the main entrance panel to smaller distribution panels called subpanels or load centers. These auxiliary panels are located in remote parts of a house or in outbuildings, and they are used for redistribution of power, such as in a garage. Feeder circuits aren’t found in all houses. All of the circuits in a home that run from either the main entrance panel or from other smaller panels to the various points of use are branch circuits.

For 110-120-volt needs, a circuit branches out through a circuit breaker from one of the main buses and from the ground bus. For 220-240 volts, many circuits use only the two main buses. But all three wires are needed for devices that operate on both 110-120 volts and 220-240 volts. The 110-120-volt branch circuits go through fuses or breakers, which are labeled either 15 or 20 amps. The 15-amp branches go to ceiling lamps and wall receptacles in rooms where less energy-demanding devices, such as table lamps, are found. The larger 20-amp circuits go to receptacles in the kitchen, dining, and laundry areas where heavy-duty appliances are used.

A circuit can handle a certain amount of wattage, with a 15-amp circuit handling up to 1,800 watts and a 20-amp circuit handling up to 2,400 watts. However, it is recommended to limit the load on a 15-amp circuit to 1,440 watts and a 20-amp circuit to 1,920 watts. To determine the load on a circuit, add up the wattages of all appliances and lamps plugged into it. Take into account motor-driven appliances that draw more current when starting up. Regularly examine wiring for safety reasons and replace cords with damaged insulation. When working on a circuit, always turn off the power and take precautions to ensure that the power does not accidentally turn back on. Some electrical repairs require a licensed electrician, but many can be done by a do-it-yourselfer as long as safety is the first priority.

  • To ensure safety when working on an electrical circuit, all wire joints and connections must be made inside an approved electrical box. There are different methods for joining wires, but the most effective way is to use crimp-on or screw-on wirenut type solderless connectors. It is crucial not to connect wires behind walls or ceilings that are not accessible by opening an electrical box. Additionally, when joining insulated wires, ensure that no uninsulated or bare wire extends beyond the connection. The insulation should go right up to the solderless connector or terminal screw.

  • One of the best ways to join wires is to use solderless connectors called wirenuts. Twist the conductor ends together, and screw the wirenut into the twisted ends. Ensure that no bare conductor is exposed.

    Everyone in the family should know how and where to throw the master switch that shuts off all electrical current.

  • If there is a risk of contact between water and electricity, avoid wading in water until the master switch has been shut off.
  • Always assume that an electrical receptacle or apparatus is energized until proven otherwise by using a circuit tester or pulling a fuse/tripping the disconnect plug.
  • When working with electricity, use only insulated pliers.
  • When working with a fuse box or circuit breaker box, stand on a dry board or wooden platform. Also, use a wooden stepladder instead of an aluminum one to minimize the risk of shock while working with electrical wiring.
  • To save time, determine which electrical circuits activate which receptacles in your home and then create a diagram or print the information inside the circuit breaker or fuse box.

Electrical Grounding

Proper grounding of your electrical system is crucial for your safety. Electricity always follows the path of least resistance, which could be you if an appliance or another electrical component is not grounded.

Grounding directs electrical energy into the earth by providing a conductor that is less resistant than you. This is achieved by attaching one end of the wire to the frame of an appliance and fastening the other end to a cold water pipe. The majority of plastic-coated electrical cables contain a bare wire that carries the grounding connection to every electrical box, receptacle, and appliance in your home. You can typically determine if your electrical system is grounded by examining the receptacles. If you have the type that accepts plugs with two blades and one prong, your system should have three wires, one of which is the grounding wire. The prong carries the safety ground to the metal frame of any appliance that has a three-wire plug and cord.

The metal frame of an appliance can pose a safety hazard to you and your family. If the insulation of a power cord wears away at the point where the cord enters the metal frame, contact between the metal current conductor and the metal frame could make the whole appliance alive with electricity. Touching a charged metal frame of the appliance while simultaneously touching a water faucet or a radiator will make the current surge through you.

Throughout the electrical system, there are various points where contact between conductor and metal can occur, posing a safety risk. It is important to regularly inspect, maintain, and repair these areas, such as where wires enter a metal pipe, where cords enter lamps or sockets, and where in-wall cables enter electrical boxes. These contact points must be free of burrs that could damage the wire’s insulation, and washers and grommets should be used for protection. However, the best way to ensure safety is to have a grounded system without any breaks in the circuit.

Electrical safety should always be a top priority during home repairs, and it is wise to call a professional electrician when necessary. In the following pages, we will discuss how to restore a circuit and what steps to take during a power outage.

The fuses and circuit breakers in your home electrical system are designed to trip or blow if the circuit is overloaded. If this happens, it is important to take the right steps. Before a circuit trips, make a list of all the branch circuits in your home and which areas they control. You can then identify which receptacles and fixtures are on each branch circuit. Verify the list by removing a fuse or tripping a circuit breaker to its OFF position and checking which equipment or devices are deenergized. Once you know which items are connected to each branch circuit, record the information on a card and attach it to the main entrance panel.

When a circuit goes off, there may be visual or audible signs of the problem, such as a bright flare or sparking sound. Disconnect the faulty equipment and check the main entrance panel to see which fuse has blown or which breaker has tripped. Determine which receptacles, appliances, and lighting fixtures are on the circuit and disconnect everything you can. Check the fixtures you cannot disconnect for signs of malfunction. If the circuit holds after replacing the fuse or resetting the breaker, check for short circuits or remove some of the load from the circuit if it cannot handle the current draw.

If a new fuse blows or the circuit breaker cannot be reset, the issue may be with either the connected equipment or the circuit cable itself. Check all connected items and examine each for faults until the problem is found. If the circuit still fails when there are no loads connected, then the wiring is likely faulty, possibly due to a short in a junction or receptacle box or within the cable. If you suspect faulty wiring, seek the assistance of an electrician.

Circuit breakers are typically reliable, but they can occasionally fail. This will cause the circuit to fail to energize, even if there are no faults. If the circuit breaker has a burnt plastic smell, a loose and wobbly trip handle, or rattles when moved, it has likely failed. Turn off the circuit, check the breaker with a continuity tester, and replace it if necessary.

Coping With a Power Outage

What should you do if all power in your home goes out? Often, this is due to a power outage in the neighborhood or district, but it can also be an issue with your home’s wiring system.

Start by determining if the outage is widespread or if it’s limited to your home. If it’s nighttime, check if your neighbors’ lights are out. During the day, call a neighbor to see if they are affected. If you have a circuit breaker, check if it has tripped to the OFF position. For fuse blocks, pull them out and test them with a continuity tester.

If the issue is a general power outage, contact the power company. If your main breaker is on, and your neighbors have power, but you do not, the problem lies between your main entrance panel and the power transmission lines. Call the power company, as this is their responsibility. If you find a tripped main breaker or blown main fuses, do not attempt to reset or replace them. The issue may be a system overload or a dead short within the house.

Start by turning off everything in the house and flipping all the breakers to the OFF position. Reset the main breaker to ON, and then trip the branch circuit breakers back on one by one. If one fails to reset, the issue is within that circuit, and it must be cleared of the fault.

If all the circuit breakers switch on and the main breaker remains on, there are two possible scenarios. The first is that something you disconnected earlier is faulty. You should go back along the line, inspect each item for possible faults, and plug each one back in. Eventually, you will find the one that is causing the issue, either visually or by noticing that a breaker trips off when you reconnect it. The second possibility is systemwide overloading. This is characterized by recurrent tripping out of the main breaker when everything in the house is running but there are no electrical faults to be found. To solve this problem, you can either lessen the total electrical load or install a new larger main entrance panel with new branch circuits to serve areas of heavy electrical usage and help share the total load. This job requires a licensed electrician.

The troubleshooting approach is similar if the main panel has fuses, except you’ll need a supply of fuses on hand. First, pull all the cartridge fuses and unscrew all the plug fuses in the panel. Replace the main fuses and put the fuse block back into place. Then, one by one, replace each fuse or set of fuses until the one that’s causing the outage blows out again. This is the circuit that must be cleared. General overloading, however, will cause the main fuses to go out again. If this happens, call in an electrician who can test for overloading and suggest remedies.

If your home is prone to power outages due to the local utility company, wind storms, or other problems, it would be beneficial to assemble an emergency blackout kit. This kit should include candles or oil lamps and matches for area lighting, a flashlight, battery lantern, or other auxiliary light source for troubleshooting, a correct and up-to-date circuit directory posted on the main entrance panel door, a tool kit with appropriate tools for making electrical repairs, a circuit tester, preferably the voltage-readout type, two replacement plug fuses of each amperage rating in use, preferably Type S, four replacement cartridge fuses, including main fuses, of each amperage rating in use, one replacement pull circuit breaker of a rating equal to the smallest size in use or one of each size in use, one replacement double-pull circuit breaker of each amperage rating in use, a selection of lightbulbs, one replacement duplex receptacle to match existing units, one replacement single-pole switch to match existing units, one replacement three-way or other special switches to match existing units, wire nuts, and electrical tape.

With a little preparation and knowledge, you can handle your next power outage without being left in the dark. To perform repairs and maintenance checks on home electrical receptacles, refer to the next section.

Restoring an Ungrounded Circuit in Older Homes

In older homes, residential wiring systems often use a two-wire system in the 110-120-volt branch circuits, with one conductor acting as hot and the other as neutral. However, the neutral may not serve as a ground, making the system ungrounded and potentially hazardous. This can be identified in ungrounded receptacles, which only have two slots for each plug. Modern wiring requires the installation of a third conductor, resulting in three openings in receptacles to allow for grounding. A polarity checker can be used to ensure outlets are installed properly, as polarity reversals can occur even in new wiring systems. If a reversal is detected, the circuit must be turned off and the receptacle wires switched to the correct terminals for proper operation and safety.

Replacing a Faulty Electrical Receptacle

If you come across an electrical receptacle that doesn’t function correctly, replacing it is the best solution. To replace a receptacle, you will need a replacement receptacle, screwdriver, single-edge razor blade or utility knife, grounding screws or clips, and a wire stripper with a cutting blade. Simply remove the old receptacle and connect the wires to the new one, ensuring proper grounding for efficient and safe operation.

Improper use of electrical receptacles can lead to permanent damage. Even inserting a hairpin or paper clip may shorten the lifespan of the receptacle and create dangerous situations. Plugging in an appliance with a short circuit can also cause damage, and in such cases, the receptacle must be replaced. A worn-out receptacle is also a possible explanation for inefficient and unsafe performance. Signs of a worn-out receptacle include the weight of the cord pulling the plug out or the plug blades failing to make constant electrical contact with the slots. In such cases, it is recommended to replace the old receptacle with a new one.

To replace an electrical receptacle, one must follow the correct installation procedures. Before starting work on the electrical receptacle, de-energize the circuit that controls it. Inspect the old receptacle to see if it can accommodate a plug with a round prong for grounding, and buy a new receptacle of the same type (grounded or ungrounded) with a 20-amp rating. Remove the plate covering the receptacle carefully, then remove the screws holding the receptacle in the electrical box. Loosen the terminal screws on the receptacle, and remove the line wires. If the wires or insulation are brittle or frayed, it is recommended that you have a professional rewire that part of the circuit.

The replacement receptacle must match the one being removed. If you have a grounded type receptacle, you must buy a receptacle with a ground terminal screw and slots for three-prong grounded plugs. Connect the wires to the new electrical receptacle, with the white wire under the silver-color screw and the black wire under the dark-color screw. If there is a green or bare wire in the box, fasten the wire under the screw with a dab of green color on it, then fasten it to the box with a grounding screw or clip. Ensure that the line wires are looped in a clockwise direction under the heads of the terminal screws so that the screw heads will pull the wire loops tighter. Connect all wires without any insulation safely under the screw heads, and clip off any excess uninsulated wire.

Carefully fold the wires into the space in the electrical box behind the receptacle, then push the receptacle into the box. If the receptacle is designed to handle three-prong grounding plugs, ensure that it is positioned correctly. Grounding plugs often attach to their cords at a right angle, so position the receptacle so that the cord will hang down without a loop. Tighten the two screws holding the receptacle in the box, then replace the cover plate and restore the fuse or trip circuit breaker.

Some electrical receptacles have slots that are not the same size; one is wider than the other. The wider slot is for the white or neutral wire, while the narrower slot is for the black or hot wire. Some plugs are designed with one blade wider than the other, and can only fit into the receptacle one way. The purpose of a polarized plug is to maintain the hot and neutral wire identity from the circuit to the appliance.

For more information, check out these related articles on HowStuffWorks:

– How to Replace a Wall Switch

– How to Rewire a Lamp

– How to Replace an Incandescent Light

– How to Install a Fluorescent Light

– How to Repair a Doorbell

– How to Install a Ceiling Fan

FAQ

1. What are some common electrical issues that can occur in a home?

Common electrical issues in a home include circuit overloads, light switches or outlets that don’t work, flickering lights, and electrical shocks. These can be caused by faulty electrical wiring, outdated electrical systems, or improper installation of electrical components. It is important to address these issues promptly to prevent electrical fires or other hazards.

2. Can I do electrical repairs in my home myself, or should I hire a professional?

While some minor electrical repairs can be done by homeowners with basic electrical knowledge, it is generally recommended to hire a professional electrician for more complex repairs. Attempting to do electrical work yourself without proper training and knowledge can be dangerous and potentially cause more damage. Always prioritize safety and consult with a licensed electrician when in doubt.

3. How do I safely turn off the power to my home before starting an electrical repair?

Before starting any electrical repair, it is important to turn off the power to your home to avoid electrical shock. Locate your home’s main electrical panel and turn off the circuit breaker or remove the fuse that controls the area where you will be working. Use a voltage tester to confirm that the power is off before beginning your repair.

4. What tools do I need for basic electrical repairs?

For basic electrical repairs, you will need a voltage tester, wire cutters and strippers, electrical tape, a screwdriver set, pliers, and a flashlight. Depending on the repair, you may also need a wire nut or a replacement electrical component, such as a light switch or outlet.

5. How do I replace a light switch or outlet?

To replace a light switch or outlet, turn off the power to the area where you will be working. Remove the cover plate and unscrew the switch or outlet from the electrical box. Carefully disconnect the wires from the old component and connect them to the new component in the same way. Screw the new component into the electrical box and replace the cover plate. Use a voltage tester to confirm that the power is back on before using the new switch or outlet.

6. What should I do if I encounter a problem that I am not comfortable fixing?

If you encounter an electrical problem that you are not comfortable fixing, or if the repair is beyond your skill level, it is important to contact a licensed electrician. Attempting to do a repair that you are not qualified to do can be dangerous and can cause more damage to your home’s electrical system. Always prioritize safety and consult with a professional when in doubt.

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