What Busbars are and How They Work



Electric panels have a few complex components that make it possible to deliver electricity to the various circuits in your home or business. Without those panels, we wouldn’t be able to live the style of life that many of us live.

One of the components within the average electrical panel is called the busbar. This metallic bar carries electric power from incoming feeders and moves them through outgoing feeders. Think of it as the electrical junction. That’s just the start of what there is to know about electrical busbars.

What a Busbar is and What its Purpose is

It helps to know what busbars are to begin with. To put it simply, it is something of an electrical junction in the average electrical panel. It is the metallic bar that carries electrical current from a plethora of incoming feeders and distributes that current to the outgoing feeders.

Busbars have a litany of purposes across both residential and business settings. They can come in a wide range of different configurations. The goal is to provide sufficient reliability, keep costs to a minimum, and create better operating flexibility. Circuit breakers are arranged on the busbar in order to maximize available operations.

The Different Types of Busbars

Despite a simplistic explanation of what a busbar does, there are a couple of different busbar types to be aware of. Let’s look at the three different types: the single busbar system, the double busbar system, and the ring busbar system.

Single busbar system. As the name implies, there is only one busbar used in this system. There are fewer incoming and outgoing lines involved with a single bar system. You might use a pair of incoming lines that get connected through the isolator and circuit breaker. Single and three phase lines are connected by the circuit breaker, isolator, and step down transformer. This kind of system can have a sectionalized arrangement through the addition of circuit breakers as required.

Double busbar system. When a second busbar is added, there is typically one that handles low voltage operations while the other handles high voltage operations. There is the option to add other busbar systems here as well. There is a coupling switch used for transferring operation between the two busbars.

Ring busbar system. There are two circuit breakers in this arrangement that serve on a single line. You might have circuit breakers 1 and 2 on a single line, with circuit breakers 3 and 4 on another line. There are always a pair of parallel paths to reach the circuit. Because of this, a failure of one path won’t cut off service completely.

Busbar System Advantages

Why would you use any one of these systems? There are inherent advantages that come along with using each of them. Of course, there are downsides to be aware of. Here are the pros and cons of using different busbar systems.

Advantages of a single busbar system. Maintenance for this busbar type is very easy and low cost. The real perk is that a fault in one part won’t completely shut down the entire system. That said, you need to conduct a complete shutdown to make any additions to the busbar system.

Advantage of a double busbar system. The only downside to this system is the high maintenance cost but there are several perks. For one, even a fault won’t prevent an undisrupted supply of electricity. Testing of feeder circuit breakers can be done without having to shut down the system as well.

Advantages of a ring busbar system. Maintenance can be done without interruption of power, and failure of one system won’t interrupt service. That said, it can be tough to add a new circuit line.

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