Busbar and Bus Duct: How to Build Resilience into Power Distribution Systems

Bus duct power distribution systems in a data center

What is a busbar?

Busbar and busbar trunking systems and bus ducts (often spelled bus bar or buss bar) are types of electrical conduit used to distribute power to various electrical devices and systems within a building or facility. They are made of copper or aluminum, typically insulated to prevent electric shock.

Types of busbar

Busbars come in a variety of forms, each with unique benefits and some drawbacks. Among the busbar varieties that are most frequently used are:

Solid busbars

These are the most basic and economical types of busbar. They are constructed from a single metal section, such as copper or aluminum. The purpose of this busbar is to carry the electrical load and dissipate heat.

Copper and aluminum busbars

Copper and aluminum (or for the non-US speaking community, aluminium) busbars are used to connect various electrical system components in electrical panels and switchgear. Being made of copper or aluminum, they are highly conductive, making them more corrosion-resistant.

What is a busbar used for?

Busbars are used in many environments across multiple industries in a variety of applications, including:

  • Electrical switchgear
  • Power distribution systems
  • Motor control centers
  • Battery banks
  • Solar panels
  • Wind turbines

Discover how to identify potentially faulty bus duct or busbar joints before they occur.

Difference between bus duct and busbar

Busbars, are metallic strips or bars that conduct electrical current in a piece of electrical switchgear. They are also found in bus ducts, which are sheet metal ducts containing a series of busbars and are used in place of traditional conduits in electrical installations due to their versatile and quick method of installation and modification.

Bus ducts are frequently utilised in situations where there is a risk of damage to the bus bars or where the bus bars are exposed to the weather.   

Typically, a bus duct system consists of a series of conductors or 'buses' made of copper or aluminium that run parallel to each other and are connected to a power source. 

Why is Bus duct important for conducting electrical power?

Bus duct is important for several reasons:

  • Reliability: Bus duct provides a reliable and consistent source of power to electrical devices and systems, reducing the risk of power outages and equipment failures.

  • Safety: The metal enclosure of bus duct protects the electrical connections and cables from damage and prevents accidental electrical contact, making it safer for people and equipment.
  • Easy maintenance: Bus duct is designed for easy access and maintenance, which allows for quick repairs and replacement of components, reducing downtime and maintenance costs.
  • Space-saving: Bus duct takes up less space than traditional cable trays, making it an ideal solution for tight and confined spaces.
  • Flexibility: Bus duct can be easily reconfigured or expanded to accommodate changes in the electrical system, making it a flexible solution for different types of buildings and equipment.
  • Energy efficiency: It has the advantage of allowing better control of the power distribution which can avoid circuit overload and reduce energy consumption.

Overall, bus duct provides a safe, reliable, and efficient means of distributing power to electrical devices and systems, making it an essential component in commercial and industrial settings.

Why are bus duct joints considered the weak points?
  • Icon Electrical connections are subject to wear and tear over time.
  • Icon Vulnerable to environmental factors
  • Icon Subjected to mechanical stress
  • Icon Age - over time, the joints can become loose
  • Icon Poor installation of the bus duct

What happens when a bus duct joint fails?

When a Bus duct joint fails, it's important to address the problem as soon as possible to minimize damage and avoid costly repairs and replacements. This can be done by shutting off the power to the affected bus, and then replacing or repairing the joint as needed. It's therefore important to have a regular maintenance program to detect any potential issues before they cause a failure.

When a Bus duct joint fails, it's important to address the problem as soon as possible to minimize damage and avoid costly repairs and replacements

When a Bus duct joint fails, several things can happen:

  • Power interruption: The electrical connections at the joint may become loose or corroded, causing a break in the power supply and power interruption to the devices and systems connected to that bus.
  • Equipment failure: The loss of power can cause equipment failure, potentially leading to costly repairs or replacement of the affected equipment.
  • Electrical arcing: The failed joint may also cause electrical arcing, generating heat and sparks, resulting in a fire hazard with the potential to damage to the surrounding equipment and structures. Power quality issues: The failed joint can also lead to power quality issues, voltage fluctuations and harmonic distortion.

Digitizing electrical infrastructure

Digitization is accelerating the requirement to connect critical equipment and machinery to the internet in order to remotely acquire condition data for subsequent analysis. This is a vital component of the concept referred to as the Industrial Internet of Things (IIoT).

Digitization is defined as the connection of electrical and mechanical infrastructure and machinery to the internet to facilitate the acquisition of condition data for subsequent analysis.

IIoT is not to be confused with the Internet of Things, or IoT, which refers to the billions of devices that are connected to the internet, each performing the task of gathering and sharing data. Whilst similar principles are applicable to both IoT and IIoT as each utilizes the function of digital connectivity and the cloud to share data, the IoT is largely focused on general, or even home use. The IIoT is more focused on connecting and digitizing industrial infrastructure and systems to create the data to boost productivity and deliver more efficient practices.

Connection to the IIoT provides significant commercial benefits. It can grant users a competitive edge in areas such as cost reduction, increased productivity, and standardization of best-performing equipment, as well as a host of other advantages.

Why are bus duct joints considered the weak points?

Bus duct is manufactured in short lengths (usually no more than 3m each) and connected on-site using bus duct joints.

Electrical connections: The joints between the individual bus sections are where the electrical connections are made, and these connections are subject to wear and tear over time. This can cause resistance and arcing, which can lead to equipment failure and power outages.

Environmental factors: The joints are vulnerable to environmental factors such as moisture, dust, and temperature changes, which can cause corrosion and damage to the electrical connections. They are also heavy and over time, the effects of gravity put stress on the joints.

Mechanical stress: The joints are subjected to mechanical stress from the movement and vibration of the buses, which can cause wear and tear on the connections and the surrounding materials.

Age: Over time, the joints can become loose and the connections can become corroded, leading to a reduction in conductivity and power transfer.

Installation: Poor installation of the bus duct can lead to weak joints, which can cause problems in the future.

Regular inspection and maintenance of the bus duct joints can help to minimize these risks and ensure a reliable source of power. It's also important to use high-quality materials and proper installation techniques to reduce the likelihood of weak joints.

Prevent bus duct failures with thermal monitoring

Compromised joints will result in hotspots with the temperature rise in proportion to the severity of the fault. Thermal monitoring is therefore a useful tool for preventing bus duct failures by continuously monitoring the temperature of the bus duct, providing early warning of potential problems before they lead to failure.

Temperature monitoring: Thermal monitoring sensors installed directly onto bus duct will measure the temperature on the joints and indicate if there is a potential problem.

Temperature rise can be caused by a number of factors, such as a loose connection, a damaged bus, or an overloaded circuit.

Real-time monitoring: Thermal monitoring systems provide real-time data, which not only alerts operators to issues as they arise, but provides ‘big data’ for analysis by AI or Machine Learning, to inform a predictive maintenance model.

Remote monitoring: Thermal monitoring systems can be connected to a remote monitoring system (BMS / EPMS / SCADA), reducing the need for on-site maintenance staff.

Thermal monitoring is an important tool for preventing bus duct failures, by providing early warning signs of problems and allowing for prompt corrective action to be taken. It can minimize the risk of power interruption, equipment failure, and potentially hazardous hotspots.

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