Why dont overhead power cables have rubber/plastic cover so that if they fall they cant cause serious injury?

Question

There have been severe storms in my country Kenya and power lines have fallen and caused a lot of injuries, some fatal to pedestrians, motorists and others.I am sure if power lines were covered with rubber sheathing or some other apopropriatde material, there would be less likelihood of electrocution, serious injury, fire or property damage. I am a lay person in these matters so I am talking from what I have seen.Thanks in advance.

Answer 1

Let's see... First of all ONLY high voltage power cables do not have protective polymer insulation. Low voltage cables, like the ones that bring outlet tension to homes do have an insulation, usually made of PVC, rubber, silicone and such. The large, 10000Volts, up to and over 200000 volts and so on do not for several reasons:

1. It would be impractical to make. For usual materials, like PVC the thickness of the insulation would be extreme (I think as thick as several centimeters) as to protect from such high voltages. Such insulations would make the cables break under their own weight.

2. The cables heat up really good under the enormous currents and voltages so the insulation plastic would be close to melting point all the time.

3. PVC is quite senzitive to "weather curing". It becomes brittle and cracks if left under weather condition for several years so the insulation would still serve to no good.

Furthermore, regulations regarding aerial wiring state that they should avoid crossing populated areas, roads, etc. unless absolutely necessary. Also, wires fallen on ground should definitely not be messed with. Furthermore, if high voltage cables were insulated, this would only serve ready made combustion materials for fires in case of short circuits and damages.

I guess this takes care of your question...

Answer 2

In addition to factors cited in the above answer, I think it's a matter of cost/economy as well.



In a more developed/ wealthier country such as the USA bare high voltage power lines are hung aerially only in less populated areas and over trips of land that are called utility easements, dedicated to power transmission and no other structures are allowed to be built there. These high-voltage transmission lines are buried underground, in concrete ducts when they run through densely populated areas, a very expensive way to transmit power.



Most of the aerial lines (lines hung overhead) you see in populated areas in the US are covered (insulated) low voltage telephone lines or covered (insulated) medium-voltage power (electric) distribution lines going to neighborhoods and homes.

Answer 3

One small addition to what has been said above, and that seem to have been forgotten:

When a power cable breaks and falls to the ground, it acts exactly like a whip!

It does not matter if it were covered with feathers, the simple whipping force would STILL cut a car in two...

(I have seen a cable cutting a HOUSE in two!)

Answer 4

it really wouldnt help. and your broke *** country has better things to spend money on.