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UNIT 9: POWER AND LIGHT (electrical systems) INTRODUCTION We use electricity for light, for machines, and for many devices. The electrical system is like the nervous system of the building. It brings power to every room. STORY 1: How Electricity Comes In Electricity comes to the building from wires outside. These wires are often underground or on poles. They connect to the building at a service head. From there, the electricity goes to a consumer unit. Many people call this the fuse box. The con