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What is a busbar in an electrical panel?

What is a bus bar? This image displays the answer.

Electrical bus bars have been right in front of you the whole time!

What is a busbar in an electrical panel?

By Dhanesh Misir on June 12, 2018

If the question “What is an electrical busbar?” has ever made you think of public transportation, keep reading for some information. 

The electricity that powers our homes and appliances is a critical part of modern life, yet it’s also rife with mystery. As much as we depend on it, there is a great deal we don’t understand about electrical wiring, panels and the various components that make it all work. One question that tends to arise quite often is: “What is a busbar?” 

Whether you call them bus bars, bus-bars, or busbars, or you simply point and say “that thing,” it’s natural to have electrical busbar questions. They’re an important part of your electrical system, and if they run into problems, you’ll soon have some serious electrical issues on your hands. Electrical work is generally too dangerous for inexperienced individuals, but by getting familiar with busbars and the connections involved, you might be better equipped to identify problems with this component in the future.   
 

So what is an electrical busbar, anyway?

A bus bar is an electrical conductor, or group of conductors, that is used to collect and distribute electrical power. Busbars are maintained at specific voltages, and are typically capable of carrying high currents. Busbars can be found in electrical panels, where they act as a junction of sorts for incoming and outgoing currents. Often, they’re used to connect different circuits within an electrical system. 

Although their name might indicate a bar shape, electrical busbars can be found, among others, in rectangular, circular, and cross-sectional shapes. They consist of an isolator part, as well as a circuit breaker – when an issue occurs, the breaker is tripped and the faulty busbar section is separated from the rest of the circuit.   
 

What are the types of busbars? 

What is a busbar? Well, the answer depends on which type you’re talking about! Just as busbars come in different shapes and sizes, they’re also available in a number of different variations. The ideal busbar for a system will depend on the desired ease of maintenance, the reliability, as well as the electrical demands that will be placed on the system. Cost is also a factor, with some versions and electrical busbar connections coming with heftier price tags. 

Types of busbar system configurations include: 

  • Single busbar – Simple, straightforward configuration. A single busbar in the system offers a low initial cost and simple maintenance. This option does not provide much flexibility, and a fault will disturb the entire power supply.

What is a bus bar? It may or may not be in this picture.

If this is all confusing to you… just walk away. 

  • Main and transfer bus – This configuration uses bus couplers, which can transfer electrical loads from one main bus to a reserve bus in the event of an overload. This arrangement has less of a maintenance cost than others, and offers a safety net for overloads. On the other hand, a main and transfer bus costs much more due to having multiple busbars, and a fault on either would shut down the entire substation.
     
  • Single busbar with sectionalized bus – This configuration uses an additional breaker, and has isolating switches to prevent a complete shutdown in the event of a fault. It includes factors for decreasing fault occurrences. This system’s cost is higher due to the extra components. 
     
  • Double bus double breaker – Two breakers and two busbars maximize the system’s reliability. Neither faults nor maintenance will interrupt continuity on the entire system, as the load can be transferred between the two busbars as needed. This setup has a high maintenance cost compared to other options.
     
  • One and a half breaker – Three breakers are divided between two busbar circuits, giving each one a circuit breaker and a half. This arrangement is well suited to cases where the particularly large currents will need to be handled on each circuit. This setup protects against power supply interruptions, but it can be complicated and expensive to maintain.  
     

Exploring electrical busbar repair guidelines

Your electrical panel’s bus bar might become worn out and pitted over time, which will create the need for a replacement. If you believe you’re in need of an electrical busbar replacement or repairs, it’s important to first consider calling in professional help. 

Electrical work can be complicated and highly dangerous, especially if you’re not familiar with the components involved. If you’re comfortable with electrical work, or you just want some background information, following here are some busbar replacement steps that could prove helpful: 
 

  1. Turn off the main breaker on your panel. This breaker is responsible for all the power your home receives, and it will be the biggest breaker on the electrical panel. You’ll be doing the replacement with a flashlight, which means it would be helpful to have someone else assist you.
     
  2. Take out the screws on the panel cover before carefully removing it. This should expose the wiring within. The busbars will usually be long metal bars that run vertically through the panel.
     
  3. Using tape and a marker or pen, mark each of the wires connected to the busbars, counting in order from top to bottom. This will allow you to easily replicate the same connections on the new busbar.
     
  4. Using a screwdriver, remove all of the wires that were just labelled from the busbar.
     
  5. Once the wires have been disconnected, unscrew the busbar itself by removing the mounting screws on either end of it. Keep track of how it was oriented within the panel as you remove it, since you’ll need to ensure that the new busbar is positioned the same way.
     
  6. Using the mounting screws included with it, install your new busbar. Make sure it feels firmly screwed in.
     
  7. Use the labels to insert the wires into their original positions on the new bar. Once each wire is fitted in, use a screwdriver to tighten down your new electrical busbar connections.
     
  8. Replace and screw your panel cover back on, then restore power to the main breaker.

If these steps seem unclear for any reason, or you’re not sure of how to begin, don’t take the risk! Messing with electrical components without the proper experience can cause extensive damage to your system, in addition to the risks of severe injury and death.  

When in doubt, get assistance from the verified Experts on JustAnswer. Whether you need electrical troubleshooting advice, or you just want to ask “What is a busbar?”, they might just be able to give you some peace of mind – while also saving you a bundle. 
 

Do you know how to replace a busbar? Do you prefer to run and hide when there’s electrical work to be done? Share your preferences in the comments!