Question

The overhead cables used to transmit electrical power by the National Grid usually consist of a central core of steel cables surrounded by a sheath of cables of low resistivity material, such as aluminium.

What is the main purpose of the steel core?

Answer 1

The steel core in overhead cables provides strength and support to prevent breaking or sagging of the power lines. It is surrounded by aluminium to ensure conductivity and minimize resistance for efficient power transmission.

Step-by-step explanation:

The main purpose of the steel core in the overhead cables used by the National Grid is to provide strength and support to the cables. The steel core acts as a reinforcement, preventing the cables from breaking or sagging under the weight and tension of the power lines. The steel core is surrounded by a sheath of low resistivity material like aluminium to provide conductivity and minimize resistance, allowing for efficient transmission of electrical power.