Your Choice

Thursday 7 June 2012

Electrical Wiring

Electrical systems vary widely given their different uses. That being said, the basics of wiring something are not that hard to understand.

Wiring is the insulated conductor that carries electricity. The wire that is used in a building such as a home or a factory is called building wire. The wire inside a piece of machinery is usually called equipment wire. Wire is measured by its diameter. This measurement is known as the wire gauge. Wire gauge runs in reverse numerical order. In other words, the higher the gauge number, the smaller the wire diameter.

Electrical wiring is governed by strict codes. Electrical codes began in the 1880's at the same time the first extensive wiring was being done. In 1897, the National Fire Protection Association established the National Electric Code (NEC). The National Fire Protection Association was a group of Insurance companies that were concerned about the potential danger inherent in faulty electrical wiring. They had cause for concern. Early wire was bare or covered with cloth. There was little understanding of the need for insulation.

The NEC is used in conjunction with local, country, and State codes that strictly control electrical wiring. The codes are concerned with proper size of wire and with insulation. Factors that are considered are the expected load, the frequency of modifications, and the nature of the environment where the wire is used. Homes have small loads, infrequent modifications and a very non-corrosive environment. Commercial establishments are usually in the middle. The load demands are sometimes higher, and modifications are not infrequent. The factory or industrial site has a very high demand. Modifications are frequent, and the environment is often highly unstable.

Materials used in wire have varied over the years. Copper has always been the first choice because it is such a good conductor and is very flexible. In the 1960 to 1970's, aluminum wire became popular due to the rising cost of copper. Insulation was usually rubber although rubber tended to corrode due to exposure to moisture and air. PVC compounds are now used most commonly as wire insulation. Insulation is made in different colors to identify wiring circuits in a system.

Electrical wiring has given rise to various connectors. The place where a wire is joined to another wire or attaches to a device is the point where there is the most danger of a spark. It is important that connections are secure. Insulated plastic wire nuts are used to attach two wires. There are also special tools used by electricians to deal with the installation of wiring. An example is the combination wire cutter and stripper. The stripper is used to remove the insulation from the end of the wire so that the bare wire might be attached.

IMPORTANT: Read this before you start


Introduction
Let there be light! Unfortunately, many older homes have “outgrown” their electrical systems. When these homes were originally built, no one anticipated that we would be using as many electric devices as we do today. Over the years, new light fixtures, outlets and appliances have been added to homes that are not equipped to handle the load. The problem is that these homes are inadequately wired for the number of electric appliances most people have in their home.


If you are planning to add any new outlets, lights or appliances, it is helpful to have a map (or schematic drawing) of your electrical circuits. This will help you determine if you can tap into an existing circuit or if you need to run a new circuit from the breaker panel. In this tutorial, you will learn how to map out your houses electrical system, which will help you plan for future needs or possibly alert you to an existing circuit overload. Also, many municipalities require that your circuit box be completely labeled before reselling your home.
Skill Level & Time To Complete
• Beginner - 1 to 2 hours
• Intermediate - 45 to 60 minutes
• Advanced - 30 to 45 minutes

Cautions
You will be turning the breakers in your house off and on or removing fuses to map your circuits. Make sure you are not turning off anything critical, like a computer.

Helpful Tips
If you don’t have a circuit tester, you can use a small electric lamp to test outlets.

“Gauge” is a measurement of wire thickness. The lower the number, the thicker the wire and the higher the amp rating. For instance, 14-gauge wire has an amp rating of 15 and is thinner than 12-gauge wire, which has an amp rating of 20.



1. Before you map out your electrical circuits, it is helpful to have a basic understanding of electricity. Electricity is the flow of electrons through a conductive material. The force with which electrons are moving is measured in volts. The speed that the electrons are moving is measured in amperes or amps. If you multiply volts times amps, you get the number of watts that the circuit can safely provide. Watts is the amount of power required to run anything electric.

2. Plumbing and electricity have very similar operating principles. Volts (the force electrons are moving) are similar to the water pressure in a pipe. A thicker wire can carry more electricity (measured in amps), just like a pipe with a greater diameter can carry more water. Finally, watts measures total output of electricity, similar to measuring the total gallons of water flowing through a pipe. The greater the water pressure and the wider the pipe, the more water you will get. Electricity has these same types of relationships, except they are measured in volts, amps and watts.

3. Here is a real world example of the relationship between volts, amps and watts. Most of the outlets in your house are probably wired with 14-gauge wire. 14-gauge wire has an amp rating of 15. Standard voltage through most of your house is 120 volts. If you multiply 15 amps times 120 volts, you get 1,800 watts. If you have a circuit that goes to 9 outlets, you can have eighteen lamps plugged into those outlets, each with a single 100-watt light bulb. Anything beyond that exceeds the capacity of the circuit. This can lead to a blown breaker or possibly greater damage to the electrical system.

4. Light bulbs use a relatively low amount of watts. However, a hairdryer uses about 1,200 watts. A refrigerator uses about 350 watts and a large microwave uses about 1,800 watts. An average central air conditioning unit uses 5,000 watts and an electric range uses 12,000 watts! The point here is that each and every circuit in your house should be constructed to handle the lighting or appliance that will be using it.

5. Every circuit should be built with each component having the same amp rating. As discussed above, 14-gauge wire has an amp rating of 15. Thicker wires can carry more amps. For instance, 12-gauge wire has a rating of 20 amps, providing a capacity of 2,400 watts at 120 volts. Breakers, fuses, switches and outlets all come in varying amp ratings to match the wiring. When installing a circuit with a specific amp rating, you should make sure that you use wire, a breaker or fuse, switches and outlets that all have an equivalent amp rating.

6. Now that you have an understanding of how to calculate the load and the requirements of a circuit, you can map out and interpret the electrical system in your house. Begin by drawing a floor plan of each floor of your home. Then mark the location of each outlet, switch, light fixture and appliance.

7. Turn off the first breaker in your breaker panel or remove the first fuse in your fuse box. Make a note of the amp rating for that breaker for future reference. Using a circuit tester (or a small lamp) test the outlets in your house to determine which outlets are on that circuit. If the tester does not go on, then the outlet is on that circuit.

8. Mark the breaker number on your drawing next to each outlet that doesn’t have power. Turn light switches on and off to determine if any lights are on the circuit. Test appliances to see if they are receiving power. Mark on the drawing all of the electrical items that are on that circuit. Flip the breaker back on and turn off the next breaker. Continue the testing process until you have determined which breaker or fuse controls every light, outlet and appliance in your house.

9. To assess the load requirements for each circuit, check the watt requirements of all appliances and lights in your house. (Most appliances have this marked somewhere on the back or underside.) Add up the watts required by the lights and appliances on each circuit. Then you can compare the total watts required on a circuit to the watts that the circuit can safely deliver (volts x amps). In figure 9 you can see that many major appliances require a separate circuit to safely provide the watts that are required to run each appliance.


Now that you have a map of your electric circuits, you can safely determine which circuit you can tap into to put an extra receptacle in your bathroom or in your living room. You might also determine that you need to split a single circuit into two circuits to safely handle the load it presently requires. You are now ready to bask in the glow of soft lights or plug in your computer - enjoying your home's new power!

No comments:

Post a Comment

Tricks

Search JavaScript Kit:
 

This free script provided by
JavaScript Kit