What is Incoming Bus & Running Bus?

What is incoming Bus?

An incoming bus is nothing but a set of panel or bus bar that receives power supply from the grid or external sources.

Example: Grid supply.

What is Running Bus?

Running bus is nothing but a panel/bus bar that receives the power from the generator.

Example: Generator Power.

Significance of the incoming bus and running bus:

Both incoming bus and running bus terminology are used during the synchronization of the generator to grid or grid. Let us consider a generator, panel, grid. We can understand the concept in three cases.

Look at the image,

Case-1: The grid CB is Opened

Under this condition, the panel board receives the supply from the generator and the load is connected with the same panel will be run by using the generator power. Hence, the panel bus bar and the generator input bus bar terminal is called a running bus. Here, until the grid CB, the grid input is called incoming Bus.

Case-2: The Gen CB is opened:

During this time the panel receives the power from the grid and the entire load will use grid power. This time until gen CB such as panel board and the grid CB bus bar is called the incoming bus and the generator to gen CB bus bar is called running bus.

Case 3: Gen CB and Grid CB is Opened:

This condition is called block out, during that time, the generator circuit breaker and the grid circuit breaker will be in the open condition. The panelboard bus bar is called Dead Bus.