Wires and Cables

Wires and cables are conductors of electricity. Usually, they are made of annealed copper and are used to carry electricity to the various electrical devices and equipment on passenger cars and trucks. Wires and cables must be the right size for the application and must have proper insulation. If the wire or cable is too small in cross section or too long for its size, its resistance will be too great and valuable voltage will be lost. This will then result in poor operation of the electrical device in the connecting circuit. Wire size and length determines the resistance of the wire. Wire and cable sizes are expressed by a gauge number, which indicates the cross-sectional area of the conductor. The cross-sectional area of the wires is given in metric size or circular mils. The diameter is given in decimals of an inch. A circular mil is a unit of area equal to the area of a circle one mil in diameter. A mil is a length unit equal to .001 inches. The larger the diameter of the wire or cable, the smaller the gauge size number. Cables are made of several strands of wire. The cross-sectional area is equal to the circular mil area of a single strand times the number of strands. Special gauges are available for measuring the gauge size of wires and cables. Many multi-purpose electrician's pliers feature wire size holes for stripping, cutting, and crimping operations. When comparing cables, consider that the external diameter of insulated wire or cable has nothing to do with its current-carrying capacity. Thick insulation will make a small gauge wire look much larger. It is important that only the size of the metal conductors are compared.

About Windshield

Up until 1935 many cars had hinged windshields that could be folded on the hood of the car or opened up. Today, most windshields are stationary. They are fixed in place with a weather-strip made of rubber. The strip has a groove on the inside and a groove on the outside. The inside groove holds the glass; the outside groove holds the metal rim of the windshield opening in place. The glass "floats" in a plastic sealant that is spread out between the edge of the glass and the frame of the windshield. Windshields are made of laminated safety plate glass, which is a sandwich of glass and clear plastic. The plastic acts as a soft, protective barrier, keeping the glass in place, if it is struck during a collision. The glass sticks to the plastic to eliminate glass from flying around the interior and injuring someone. Safety glass for windscreens was one of the first passive safety devices introduced into cars in the 1930s, but its use remains a controversial question. North America and Scandinavia favor a laminated glass, which consists of two sheets of annealed glass, separated by a layer of transparent plastic. The rest of Europe and Japan favor toughened glass because it is cheaper. This type is a single sheet of glass which is heat strengthened, and which on impact fractures into small cubic fragments without very sharp edges. In recent years, laminated glass has been improved by changes in the properties of the plastic interlayer. Research has demonstrated that this new laminated glass is about 4 times safer than toughened glass, but because it is more expensive, controversy continues as to whether or not toughened glass windscreens should be banned by legislative action and replaced by laminated glass. Recent developments have combined the benefits of both laminated and toughened material in that a laminated construction is used, but the sheet next to the inside of the car is made of toughened glass.