What is a line feed from a source other than the primary feed called?

A line feed from a source other than the primary feed is referred to as back feed. In electrical systems, back feed occurs when power flows in the reverse direction from a secondary source back onto the primary distribution system. This can happen in scenarios such as when a generator is used to supply power while the primary grid is down, causing the generator's output to unintentionally energize the distribution lines, which can pose safety hazards and operational risks.

Understanding back feed is essential for linemen, as it highlights the importance of proper protective measures and isolation protocols during maintenance work. By being aware of how back feed can affect the system, linemen can take necessary precautions to ensure their safety and the integrity of the electrical grid. This distinction is crucial in the context of maintaining and operating electrical infrastructure effectively.