Getting Power To Your House

Because power is so important in our everyday lives, it's good to understand how it gets to your house. It travels along an amazing path from a power plant through a system called the power distribution grid. There is much involved along the way, including transmission substations, high voltage transmission lines, substations, fuses, transformers -- all the way down to your electric meter.

Below is a basic overview of how power reaches the typical residential customer.

  1. Power Stations  — The process begins at power stations, where electricity is initially produced. Each station is connected to others so if one shuts down, power can readily be obtained from another. Together, these facilities form the "power grid," or transmission grid.
  2. Transformers and Transmission Lines — Once created, electric current is sent through transformers to increase the voltage, allowing it to be pushed over long distances. The current is transported using high-voltage transmission lines.
  3. Substations — Electricity then reaches a substation, where the voltage is lowered. This allows it to safely pass through smaller power lines.
  4. Distribution Lines — From these smaller power lines, electricity reaches various levels of customers, as shown in the illustration below.  Residential customers (also known as "secondary" customers since they are essentially at the end of the distribution network, behind industries and businesses) are served by distribution lines in neighborhoods, where smaller pole-top transformers again reduce the voltage. The distribution system consists of smaller segments of lines, called main lines, tap lines, and service drops.
    • Main Lines — Electricity flows from substations along main lines, or "circuits" for many miles to reach communities and industries. 
    • Tap Lines — A shorter line segment between the main line and customer’s home is called a tap line, and feeds electricity into each neighborhood or small blocks of customers.  
    • Service Drop — The final stop for electricity as it connects to your house is through a "service drop," a very short line that transfers the electricity from the tap line to your meter. (Depending on where you live, distribution lines and service drops may be underground.)  The meter measures how much electricity you use.
  5. Service Panel — Wires bring the electricity from the meter to your service panel, where breakers protect your wiring from power overloads. From the panel, electricity travels through wires to various outlets and switches in your home.

Simple Electric Grid, courtesy US DOE

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