In this age of electricity, modern homes have more and more electricity built into them. In home maintenance and repair, knowledge about electricity is a must. It is important to know which electrical jobs you can handle and when to call an electrician.
People who work with electricity are called electricians. As specialists, they put wires in houses, install fuse boxes or panels, repair large electrical appliances, work on doorbells, and generally handle all common electrical equipment problems.
The most common house current is ’110 volt, 60 hertz per second alternating current (called AC). AC is a type of electricity that “alternates.” This means that it changes its direction of flow as it passes through a wire. Sixty hertz AC is electricity that changes its direction of flow 60 times each second.
Another current, 220 volt AC is also available for use in most homes. It is very dangerous to work with, and a qualified electrician should be called in if you suspect trouble in a 220 volt circuit.
Electricity may be dangerous, but it is not difficult to work with if you follow certain basic rules. The following units include the basic safety rules for working with electricity and explain simple electrical repairs you can make around the house.
When speaking of electricity, the word hot means charged with electricity. Hot also means dangerous. To avoid danger when working with electricity, follow these rules:
• Assume that all electrical wires and parts are hot
• Always check to make sure that the electricity is turned off before starting or continuing any electrical work
• Never turn on the electricity for someone else unless asked to do so
• Always check for electricity with a circuit tester
• Never work with wires or electrical equipment in wet or damp places Electricity is invisible. You can’t tell
if a wire is hot by looking at it. Things that electricity can run through are called conductors. Things that electricity cannot run through are called insulators. Electricity runs well through most metals and through water. So wires and electrical parts are made of metal. Because the human body is mostly water, it also makes a good conductor of electricity. Always be careful around electricity!
When you are working with appliances, you can turn off the electricity by pulling the plug. Most shop work is done this way. But when you are working on wiring in a house you must turn off the electricity in a different way.
All house wiring runs to a fuse box or breaker box. A fuse or breaker in this box completes each circuit. Too much electricity flowing through a wire could make it hot enough to melt and cause a fire. To prevent this, the fuse will melt or the circuit breaker will open automatically when the wires get too hot. This opens the circuit and stops the flow of electricity. The electricity can also be stopped by removing the fuse or opening the circuit breaker by hand.
The circuit breaker box and the fuse box have a main switch. This switch turns on or off all the electricity in the house. When electricians are working they will padlock the main switch in the off position and tag it.
A careful electrician tests bare wires with a circuit tester. A circuit tester is made of two wire probes and a small bulb which glows if electricity is flowing through the wire being checked.
Fuses are designed to melt and break the circuit when the flow of electricity becomes too great. Removing the fuse will also break the circuit.
The main switch on a fuse or circuit breaker box controls all the electricity in the house.
Blown fuses must be replaced. Blown circuit breakers, however, may be reset by hand.
On fuse boxes the switch may be locked open to insure that the electricity remains off. On circuit breaker boxes, the main switch is thrown and the cover is then locked.
Most circuit testers are made of two wires or probes and a neon bulb. The two probes are touched to the wires. If the bulb glows, the wires are hot (electricity is flowing). Circuit testers have different voltage ratings so be sure you are using the correct type.