Cables can be securely fixed and organized, for example by duct, cable trays, cable ties or cable lacing. Flexible or flexible cables used in mobile applications in cable ducts can be fixed using strain relief devices or cable ties. Given the wide range of cables available, it is not possible to cover all constructions. As a rule, however, the cable design has the following model: Physically, an electrical cable is an assembly consisting of one or more conductors with their own insulation and optional screens, individual covers, mounting protection and protective covers. Electrical cables can be made more flexible by wiring the wires. In this process, smaller individual threads are twisted or intertwined to create larger wires that are more flexible than solid wires of similar size. The grouping of small wires in front of the concentric stranding offers the greatest flexibility. The copper wires in a cable can be bare, or they can be plated with a thin layer of another metal, most often tinned, but sometimes gold, silver or another material. Tin, gold and silver are much less sensitive to oxidation than copper, which can extend the life of the wire and make it easier to weld.
Tinning is also used to ensure lubrication between the strands. Tinning was used to facilitate the removal of rubber insulation. The tight installation during stranding makes the cable extendable (CBA – as with telephone handset cables). [more explanations required] Stainless steel is used for medical wires and cables. Stainless steel has poor conductivity compared to copper and may need to be gold plated to improve conductivity. The figure shows the general structure of a three-core cable. The different parts are: Lead sheath cables, when laid directly on the ground, are damaged by corrosion and electrolyte. To protect the cables, corrosion layers of fibrous materials such as paper, Hessois, etc. or polyvinyl chloride are used. Layers of fibrous material distributed with the tight connection on the outside of the electrical cable are called service.
IEC 60228 “Insulated Cable Conductors” gives guidelines on the minimum number of wires in a stranded conductor for different transverse areas. Copper and aluminum wires are used as a conductive material in cables due to their high electrical conductivity. Solid wires or a number of bare copper or aluminum wires are used to make a power cable. The most commonly used dielectric in power cables is impregnated paper, butyl rubber, polyvinyl chloride cable, polyethylene, cross-linked polyethylene. Insulated paper cables are generally preferred because their current load capacity is high, usually reliable and durable. The dielectric connection used for the cable must have the following characteristics. In practice, the proximity effect is weaker than the skin effect and decreases rapidly as the cables move away from each other. The main advantage of concentric constructions is the narrow/narrow diameter tolerances that can be maintained on the scale. Concentric constructions have very smooth and uniform surfaces suitable for thin-walled insulation in high-performance applications. We already discussed the construction of underground cables in the previous article.
In this. Hybrid optical and electric cables can be used in outdoor FTTA (fiber optic antenna) wireless applications. In these cables, optical fiber carries information and electrical conductors are used to transmit energy. These cables can be placed in different environments to serve antennas mounted on masts, towers or other structures. Local security rules may apply. In medium voltage underground cables, there are two main types of insulation materials: In myCableEngineering we consider standard cable designs. Cables that deviate from it can be simulated using approximations of the standard design or special enclosure additions. Shielding and service are applied to the cables only to protect the insulation of the conductor and to protect the metal sheath from mechanical injury. The cables follow the typical construction pattern of the conductor, insulation, bedding, shielding and outer sheath. The conductors are made of copper or aluminum.
Cable stranding – Wire constructions consist of individual strands assembled in concentric or grouped configurations. Rope stranding has the advantage of increasing flexibility by using a larger number of thinner strands while maintaining a narrower diameter tolerance than a simple beam construction. Strings are lighter in larger AWG sizes such as 8 AWG and above, but there are also many applications that require the flexibility of cable constructions in smaller gauges. Constructions vary and can contain hundreds or thousands of strands. The power cable consists mainly of three main components, namely conductor, dielectric and sheath. The conductor in the cable provides the conductor path for the current. The insulator or dielectric resists the operating voltage and isolates the conductor with other objects. The sheath does not allow moisture to penetrate and protects the cables from all external influences such as chemical or electrochemical attacks, fire, etc.
The main components of power cables are explained in detail below. The term cable originally referred to a nautical line of a certain length, in which several ropes are combined to create a thick and solid line that was used to anchor large ships. As electrical technology evolved, people moved from using bare copper wires to using wire groupings and various methods of sheathing and chaining similar to mechanical wiring, so the term was adopted for electrical wiring. In the 19th and early 20th century. In the nineteenth century, electrical cables were often insulated with fabric, rubber or paper. Plastics are generally used today, with the exception of very reliable power cables. The term is also associated with communication due to its use in electrical communication. Cable-stayed bridges offer the designer a variety of possibilities, not only in terms of materials for the deck and cable, but also in terms of the geometric arrangement of the cables. Early examples, such as the Strömsund Bridge in Sweden (1956), used only two cables attached to almost the same place in height on the tower and extended to support the deck at points far from each other. In contrast, the Oberkasseler Bridge, built in Düsseldorf in 1973 over the Rhine, used a single tower in the middle of its twin spans of 254 meters (846 feet); The four cables were placed in a harp or parallel arrangement, evenly distributed both in the tower and along the bridge`s midline.
The Bonn-North Bridge in Bonn (1966) was the first large cable-stayed bridge to use a large number of thinner cables instead of relatively few but heavier cables – the technical advantage was that with more cables, a thinner deck could be used. Such multi-cable arrangements later became quite common. The bonn-north box girder deck was, like most cable-stayed bridges built in the 1950s and 60s, made of steel. However, starting in the 1970s, concrete decks were used more frequently. Note: There may be other design elements (e.g., water-blocking tape, woven fabric tape). Any influence of these on the calculations is negligible. Cable-stayed bridge designs in the United States have reflected trends in cable layout and roofing material. The Pasco-Kennewick Bridge (1978) over the Columbia River in Washington State supported its average span of 294 meters (981 feet) of two double concrete towers, with cables extending on both sides of the roadway to the concrete deck.
The same designers created the East End Bridge (1985) over the Ohio River, which has a large span of 270 meters (900 feet) and a small span of 182 meters (608 feet). The single concrete tower has the shape of a long triangle in the direction of the farm, and the cable layout is fan-like, but while the Pasco-Kennewick Bridge has two parallel cable assemblies, the East End has only one set that extends from a single level over the two-level tower on the composite steel and concrete deck. so that if you switch from a pure profile to a longitudinal view, the cables are not optically aligned. The Sunshine Skyway Bridge (1987), designed by Eugene Figg and Jean Mueller over Tampa Bay, Florida, has a prestressed concrete main span of 360 meters (1,200 feet). It also uses a single level of cables, but these remain in a layer that extends into the middle of the bridge. One or more electrical cables and the corresponding connectors can be formed into a cable assembly[1], which is not necessarily suitable for connecting two devices, but can be a partial product (e.g.