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Power box is another name for a transformer, which is the link between the main electrical grid and the local grid. These boxes take electricity from the main lines and bleed it off into the systems that connect directly to homes and businesses. Some areas use round cylinders that are up on the tops of power poles while other areas use rectangular boxes that sit on the ground. In the United States, the cylinders are typically silver and the boxes are usually a drab green or light brown. In other parts of the world, both components are typically matte silver or gray.
The main electricity grid operates at a much different power level than the wires that lead into buildings. In order to create power levels that are safe in typical buildings, power companies will use a power box to transform the electricity from one form to another. This is done automatically inside the boxes through a process called induction.
Inside a power box is a set of coils, one connected to the main grid and the other connected to the local grid. These coils don’t actually touch each other at any point; they are only connected to their respective grids. As power flows through the main coil, it moves into the local coil via electromagnetic induction. The power moving through the coils creates a magnetic field and that field allows power to move through the system without physical connection.
The induction performed by the power box prevents harmful levels of electricity from entering into the local grid. The construction of the local coil prevents most power spikes and will buffer the local grid from problems in the greater network. In fact, transformers are usually designed to fuse or explode rather than let harmful electrical current into the system where it could destroy electronics and start fires.
In most countries, a power box is a dull silver color. This is the natural color of the cold-rolled steel commonly used for their outer casings. In the United States, the silver color is often used in locations where the components are difficult to access, such as the parts of an electrical substation or high up on electrical poles. The components that are left in open areas are usually painted in a drab color that helps them blend in with their surroundings, such as green near grass and brown near sand.
The electric fuse or breaker boxes inside homes are sometimes called power boxes. These boxes have a similar function, protecting inner circuits from overload, but don’t actually transform the power. These boxes actually shouldn’t even interact with the power flowing through them unless there is a problem like a short or overload.