Electrical wires bring light and power into spaces where they’re needed. But electrical wires have to meet safety standards.
These standards are based on wire gauge, current-carrying capacity, and environmental conditions. Standard electrical wiring is designed to run indoors in dry, moderately warm, and non-corrosive environments. For electrical services, contact the experts at West Chester PA Electricians.
It all starts with the supply cable that sets out from the meter and goes into your distribution board, also known as the fuse box. From here on, it’s your responsibility.
The wires in an electrical installation carry electricity from the breaker box to each outlet, switch, and fixture. They are insulated to prevent them from conducting electricity with each other or with the metal conduit they run through, and also to protect the insulation from chemicals, heat, and light. Electrical wires may be solid or stranded and are usually marked to indicate their function and the circuit they belong to. They also have a gauge, which indicates the diameter of the conductor and the current it can safely carry.
Each electrical component has a maximum current rating that it can handle, and using the incorrect size of wire will damage it. For this reason, it is important to carefully read the instructions for each electrical component and choose the appropriate wire to use with it.
Electrical wiring must be installed with the proper wire size and type, as well as protected from exposure to the weather. This is done by running the wires through a special bendable pipe, called a conduit, or through one of several varieties of metal or plastic tubing, such as PVC or HDPE. Metal or rectangular-cross-section plastic raceways with lids are also used for some installations.
Before beginning any electric work, always disconnect the power at the breaker box and then use a voltage tester to ensure that no one is still connected. Then draw a wiring diagram of your home to determine the location and path of each wire. Start with the longest runs first to avoid wasted conduits in walls, and pull each of the wires to its corresponding outlet or switch.
Switches
There are many types of switches used in electrical circuits. The most common type is a single-pole switch. These are typically installed in wall boxes that are labeled with the switch’s name or a description of its function. Switches can also be combination devices that contain two switches and a receptacle or appliance, such as a garbage disposer. These are usually labeled as three-way or four-way switches.
Three-way and four-way switches have more complicated wiring than a simple single-pole switch. It’s important to understand how they work because a mistake in the wiring can lead to a fire or an electric shock.
The first thing you should do before installing any switches or other devices is to turn off the power to the circuit that will be affected. If the switch you’re working on is powered by electricity, it will be extremely dangerous to touch or handle.
When the power is off, disconnect the wires from the old switch. Make sure the switch box is clean and that there’s enough space for a new switch. Match up the screw terminal connectors on the new switch with those on the old one to ensure that you’re connecting the right wires. If you’re working with a three-way switch, make sure you connect the same color of wire to each pair of screw terminals.
New single-pole switches have a green grounding screw that must be connected to the home’s electrical system ground. This can be done by pigtailing it to the existing green wire or running a new wire from the switch box to the circuit’s grounding location.
Outlets
Using electricity is such a part of everyday life that we don’t often consider what goes on inside the walls of our houses when we turn on a light, plug in the microwave, or use the bathroom fan. But if you’re planning to install new outlets, it’s good to know how they work to ensure your home stays safe.
A standard outlet typically has three distinct holes that each serve different purposes. The larger hole is for ground, or “neutral,” as it’s known in the parlance of electricians. The smaller vertical slit is for hot, or power. The third hole is used for the grounding wire, which is important for preventing electric shock.
In addition to the standard duplex receptacles found in most rooms, there are also GFCI (ground fault circuit interrupter) outlets that help prevent electrical shock hazards in damp locations like bathrooms and kitchens. There are also tamper-resistant outlets, which use internal springs to keep foreign objects from entering the outlet opening and causing damage or a fire.
It’s best to have an electrician install these types of outlets, especially if you are running new circuits or extending existing ones. The process involves significant wiring and is more complex than just replacing an outlet cover plate with a childproof one. It’s also not as simple as plugging a cord into an existing outlet, which requires removing the old receptacle and ensuring that all the connections are secure.
Circuit Breakers
The circuit breaker is responsible for keeping your electrical system in tip-top shape. It senses how much current is flowing through it and, if things start to go awry, shuts off the flow of electricity automatically by “tripping,” i.e., closing the breaker’s contacts. This helps prevent fires, system damage, and injuries from electrocution.
First, remove the panel cover and make sure all breakers are turned off. Using a non-contact voltage tester or multimeter, test to see if any circuits still have power. If you have a main breaker that is out of service, call an electrician.
Next, decide which breaker to install. The wattage of the devices you’ll be connecting to the new circuit will determine whether it needs to be a 15- or 20-amp breaker. Remember that receptacles can’t be installed on more than one 15-amp circuit, and lighting can only be on two 20-amp circuits.
Unscrew the terminal screw of the old breaker, loosening it but not removing it entirely. If you’re installing an AFCI or GFCI breaker, it will have a coiled white pigtail wire that needs to be attached to the neutral bus bar. Locate the wire and find the end that matches the exposed end of the pigtail wire, then place it between the terminal plates and tighten the screw. You should hear a click as the breaker snaps into place on the hot bus bar.
Fuses
Fuses are an essential part of any electrical installation. They are an overcurrent protective device that can be installed to guard against surges that risk health and damage appliances, as well as cut the power to a faulty circuit in the event of a short circuit or mismatched load connection.
Fuses operate by self-generating heat under conditions of excessive current to interrupt the flow of electricity. They are rated in terms of current capacity and maximum allowed voltage rating. This information is used to determine if the fuse will fit a particular application and not cause damage or injury.
As with a standard wire’s ampacity, the fuse’s current rating is based on its gauge and material. But unlike a normal wire, the length of the fuse does not influence its current rating. This is because the length of a fuse is mainly determined by its internal resistance.
Fuses come in a wide variety of shapes and sizes with different time and current operating characteristics. Fuses are also rated for their cold resistance and voltage drop. These values are designed to ensure that the fuse interrupts current with minimal disturbance to other circuits. Fuses are often coordinated so that the minor branch fuse blows before the major fuse melts, preventing current from continuing to other circuits after a fault is eliminated.
Light Fixtures
The lighting you have in your home is an important part of its overall look and function. There are many different styles of fixtures available to fit your style, budget, and lighting needs. Track, surface-mounted, and recessed lights are just some of the types you can choose from.
When installing a light fixture, it is always best to have a licensed electrician. However, some individuals are able to tackle simple light fixtures on their own, provided they have the proper equipment and follow all safety rules. It is also recommended to consult with the local code to see if you require a permit to do this type of work.
Before doing any electrical work, turn off the power to that room at the breaker panel and use a non-contact voltage tester to make sure there is no current running through the wires you plan to disconnect. Turning off the power can protect you from a dangerous shock and prevent further damage to your wiring.
Once the power is off, it’s time to take down your old fixture and get ready to install the new one. Most light fixtures come with a bracket that attaches to the existing electrical box. You may need to screw the bracket into place, or it may be a snap-in type. Either way, it should be attached securely and have no loose spots or holes in the bracket or electrical box. The wires in your fixture should all have black (hot), white, and bare wires. Connect the new bare wire to the exposed end of the existing black wire by twisting them together and using a wire connector, then connect the white and copper (ground) wires as specified by your fixture’s instructions.
