Your Friendly Local Electrician

Posts Tagged ‘electrical box’

Everyone use electricity to power our homes, business, televisions , lights, etc. With AC or “Alternating Current” , the current alternates in direction on a regular basis.  This has shown to be a better way for providing electricity than “Direct Current” Electricity or DC Electricity.  This is because the voltages can be changed if needed. Using AC electricity in homes also allows for other devices to be used

While direct current (DC) electricity flows in one direction through a wire, AC electricity alternates its direction in a back-and-forth motion. The direction alternates between 50 and 60 times per second, depending on the electrical system of the country.  This change happens in a cycle.  Each cycle is also called a Hertz (Hz).

AC electricity is created by an AC electric generator, which determines the frequency. What is special about AC electricity is that the voltage can be readily changed, thus making it more suitable for long-distance transmission than DC electricity. But also, AC can employ capacitors and inductors in electronic circuitry, allowing for a wide range of applications.

We say AC electricity instead of simply saying AC, since that is also the abbreviation for air conditioning. You need to be specific to avoid confusioning issues and to avoid any misunderstandings while discussing a topic like this.

With an AC generator, a slightly different configuration alternates the push and pull of each generator terminal. Thus the electricity in the wire moves in one direction for a short while and then reverses its direction when the generator armature is in a different position.

The charge at the ends of the wire alternates between negative (−) and positive (+). If the charge is negative (−), that pushes the negatively charged electrons away from that terminal. If the charge is positive (+), the electrons are attracted in that direction.

AC electricity alternates back-and-forth in direction 50 or 60 times per second, according to the electrical system in the country. This is called the frequency and is designated as either 50 Hertz (50Hz) or 60 Hertz (60Hz).

The regular back-and-forth motion of the electrons in a wire when powered by AC electricity is periodic motion, similar to that of a pendulum. Because of this periodic motion of the electrons, the voltage and current follow a sine waveform, alternating between positive (+) and negative (−), as measured with a voltmeter or multimeter.

There are distinct advantages of AC over DC electricity. The ability to readily transform voltages is the main reason we use AC instead of DC in our homes.  The major advantage that AC electricity has over DC electricity is that AC voltages can be readily transformed to higher or lower voltage levels, while it is difficult to do that with DC voltages.  Since high voltages are more effecient for sending electricity great distances, AC electricity has an advantage over DC. This is because the high voltages from the power station can be easily reduced to a safer voltage for use in the house. Changing voltages is done by the use of a transformer. This device uses properties of AC electromagnets to change the voltages.

AC electricity also allows for the use of a capacitor and inductor within an electrical or electronic circuit. These devices can affect the way the alternating current passes through a circuit. They are only effective with AC electricity. A combination of a capacitor, inductor and resistor is used as a tuner in radios and televisions.

The National Electrical Code says that no splices are allowed outside of junction boxes. However, it seems that older homes were not built with this in mind. They have lots of wires hanging out that are not in a protective box. A wire splice should always be placed in a protective box and covered with a box cover. Before correcting this problem, as with any other electrical fix, turn the power off to the circuit that you’ll be working on. This is the very first thing that you should do when attempting to work with electricity. This may involve turning off a circuit breaker or unscrewing a fuse. Safety should be your first concern. Use a tester to check the connection and see that it really is off before proceeding. Check for power between the hot wire and the neutral wire to see if there is any power present.

Once you know the power is off, take the wire splices apart so that junction box can be added.

To install a junction box, first pull the two wires back so that the box can be added. Remove two of the box’s knockouts to allow the wires access to the box. Install cable connectors in these holes and tighten the locknut with pliers. The wire will slide into the connector and can be tightened with a screwdriver. Now, install two screws through the small holes in the back of the box to secure the box to the wooden joist.

After the box is secure, use linesman pliers to twist the wires together. To do this, join like colors, black to black, white to white, bare copper to bare copper and twist them together evenly. Add a wire nut to cover the connection. In this case, I’m using red wire nuts to make the connections. You may want to use a green-colored wire nut on the ground (bare copper) connection to symbolize the ground connection.

Once the wires are covered, it is time to install a cover plate. The wires must now be formed into the box so that the cover will go on effortlessly and the mounting screws do not screw into the wire insulation. Tuck the wires into place and place the cover over the two mounting screws. Tighten the screws and you’re ready to turn the circuit back on. After restoring power, go to the device that the splice is feeding and make sure that the circuit is indeed on. If so, you have successfully installed a junction box and made your home safer in doing so.