national grid

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The network of cables and wires, carried overhead on pylons or buried under the ground, that connects consumers of electrical energy to power stations, and interconnects the power stations. It ensures that power can be made available to all customers at any time, allowing demand to be shared by several power stations, and particular power stations to be shut down for maintenance work from time to time.

In the countryside the grid is highly visible as the cables and wires are supported on pylons. Nearer to towns and villages the cables are usually buried underground. Electricity in the UK is generated at about 25,000 volts, but before transmission through the grid, step-up transformers increase the voltage to 275,000 volts or 400,000 volts. Increasing the voltage reduces energy losses in the cables. As the grid approaches local users, the voltage is decreased to safer values using step-down transformers. The mains supply in the UK is alternating current (AC) with a frequency of 50 hertz.

The Star of May recalls the declaration of independence on 14 May 1811. The colours were inspired by the French tricolour. Effective date: c. 1990. >>