Why are telephone wires left longer than the distance between the poles?

Why are telephone wires left longer than the distance between the poles?

Originally Answered: Why are telephone wires hung loose between the poles? Quite simply the nearer to the horizontal any given cable is strung, the higher the tension that has to be applied. It’s impossible for any cable to be tensioned to be perfectly horizontal as that would require an infinite tension force.

Why are telephone wires slack?

Why do the telephone wires get slackened in summer and get tightened in winter? In summers due to excessive heat, the temperature of the wire increases and wires expand. Also, Young’s modulus decreases and hence wires slack down. In winter, the temperature of wires decrease and wires contract.

Why arent telephone wires pulled tight?

All cables have a tensile strength, and if you pull a cable tighter than that, it will snap. So, you could, for example, pull the cable extremely tight in hot weather and in cold weather, the cable contracts until its tensile strength is exceeded.

Are telephone poles disappearing?

They may stand there in another way, but they won’t disappear; they may be replaced by cable tunnels in urban area, but they will still stand in rural area.

Why do telephone wires sag in summer?

Since metals expand with a rise in temperature, therefore telephone wires sag in summers. The wires are intentionally left a bit loose otherwise in winters they would contract and break. Thermal expansion is the tendency of materials to expand when exposed to heat.

Why telephone wires are kept tight between the two poles in winter?

Telephone wires are kept tight between the two poles in winter because the cores of overhead wires are made from copper. The higher temperatures in summer make the copper expand – so the lines get slightly longer. In winter, the reverse happens – the lines contract and tighten up.

Why do electrical overhead wires hang loosely instead of being stretched tightly?

During transmission of electricity, heat is being dissipated. The heat generated by cables is being minimized via high voltage transmission. So, the cables are loose so that even if contraction should occur, there won’t be much tension which would lead to the damage of the cables.

Why are electrical wires not hung tightly?

Linear expansivity of metals: Under sustained relatively high temperatures, metals tend to expand. As a result, engineers have to plan for this in foresight and therefore, metal wires are never hung tightly. Originally Answered: Why are electric wires left sagging between poles rather than being stretched tight?

Why are the wire that is connected in the posts are slightly saggy not tightly tied by the line man?

Why the electric wire that is connecting in the post outside a little bit saggy and not tightly tied? So that it will not break once the wire will expand c. So that it will not hard for the line men to reach it.

Why do telephone poles still exist?

They’re used to lower the amount of voltage between the primary wires and secondary lines. Without transformers, there would be lots of fried household appliances. Remember, there are an estimated 180 million utility poles around the United States today.

Why are wires kept loose?

Heat makes metallic wire expand and cold makes the material shrink. Therefore, without a slack they could become too tight and break in winters or pull loose from their anchors in summers . This is the reason why wires are kept slightly loose when they are laid.

Why do cable cables droop?

Cables “droop” because they have to carry their own weight, which means some of the force that they carry is always going to be vertical. Where w is the unit weight of the wire, L is the span length, and T is the cable tension. That means you have to double the cable tension to halve the droop.

What is the top wire on a utility pole called?

Usually, the top three wires — which are called primary conductors — carry most of the electricity on the pole. As you come down the utility pole, the next set of wires consists of secondary conductors. They typically deliver power to buildings and homes. The lowest wires are cable and telephone lines.

How are telecommunication wires attached to a telephone pole?

Telecommunication wires are attached to the poll using a messenger known as strand. The strand is bolted and clampes to the pole and the fiber or coax is then lashed to the strand. In case anyone was wonder how everything besides power is attached. Haha! 8 clever moves when you have $1,000 in the bank.

How long do utility poles last?

In the Northeast, the average life of a distribution pole is 56 years old. Yet, some of these poles are still present for decades after this, some lasting for 85 years. 3. Utility pole wires carry more than just electricity