Question by Andy: Why are the cables of the national grid carried high above the ground?
Why are the cables of the national grid carried high above the ground rather than being buried underground? Thanks
top feedback:
Answer by platty
In UK the national grid voltage is 400,000 volts or 400KV
At this voltage the thickness of insulation required to make the cables safe would be huge. Just look at the size of the glass insulators on which they are suspended.
Also the cables are uninsulated in fresh air so the wind helps to keep them cool
In Large cities where 275KV cables have to be run underground they are very expensive often having hollow centres through which oil is circulated to cool the cables
The simple answer is excessive cost compared to overhead system
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