Busbars – often also referred to as collector bars, busbars or busway ducts – are central components of electrical power distribution. They carry large currents in confined spaces, are mechanically stable, and can be expanded modularly. In deconstruction projects, during the strip-out of technical installations, or in tunnel construction, professionals regularly encounter busbars in switchgear, production lines, crane runways, or as contact rails. For tasks such as concrete demolition and deconstruction, selective cutting, and the safe exposure of embedded components, a precise understanding of construction, risks, and suitable dismantling techniques is crucial. The practical relevance is diverse: when removing reinforced concrete with concrete pulverizers, when controlled splitting of foundations with rock and concrete splitters, or when separating metallic attachments with hydraulic shear tools, the proximity to busbars directly affects planning and execution. Hydraulic power units supply the tools with the required energy, which is a logistical advantage in confined or shielded areas.
Definition: What is meant by busbar
A busbar is a solid, usually rod- or strip-shaped conductor made of copper or aluminum that distributes electrical energy with high current-carrying capacity. It appears as an open collector rail in switchgear, as an enclosed busbar system (busway) in buildings and industrial halls, or as a contact rail in rail and tunnel environments. Typical features include lower contact resistance compared to cable connections, defined short-circuit withstand capability, and a mechanically robust support system. Depending on the application, busbars are executed insulated, partially enclosed, or fully enclosed, with precisely fitted supports, insulators, expansion joints, and feeders.
Structure, materials and technical parameters of busbars
The base body of a busbar is typically made of copper (high conductivity, compact form factor) or aluminum (lower weight, larger cross-section for the same current). Conductors are coupled via connectors with defined contact pressure, mounted in supports, and—depending on the protection required—insulated or integrated into a housing. Key parameters include permissible current-carrying capacity for a given temperature rise, short-circuit withstand (peak and steady-state), degree of protection against contact/moisture, creepage and clearance distances, as well as mechanical load-bearing and bending stiffness. In deconstruction scenarios, thermal expansion, the location of expansion pieces, the quality of contact points, and the anchoring bolts in concrete also play a role.
Material selection and contact technology
Copper enables compact bars with high continuous current ratings; aluminum offers advantages in weight. Contact points are made via clamps, compression connectors, or bolted joints; they are critical for heating and contact aging. Oxide layers, loose screws, or incompatible contact materials increase contact resistance and promote arcing.
Insulation and enclosure
Open collector bars are often housed within switchgear assemblies and require defined protective clearances. Insulated bars feature shrink or cast insulation. Enclosed busway systems combine conductors and housing and provide enhanced protection against contact, fire, and moisture. For dismantling, housing covers, joints, and tap-off points are the key intervention points.
Mechanical fixation
Insulators, busbar supports, and carrier profiles transfer forces into the building structure. Spacing and anchorage are sized for vibration and load cycles. During concrete demolition, locating and carefully releasing these fixations is essential to avoid uncontrolled movement of the bar.
Electrical and thermal parameters
Busbars are designed for permissible heating. Ambient temperature, grouping, installation height, and ventilation influence current-carrying capacity. Short-circuit forces act impulsively; supports and connectors must absorb them. These relationships determine the safe sequence for exposure, cutting, and removal.
Types and applications of busbars
In practice, three basic forms are encountered: open collector bars in low- and medium-voltage systems, enclosed busbar systems for power distribution in halls, high-rise buildings, or tunnels, and contact rails in rail transport. Crane runways and conveyor systems often use laterally insulated supply rails. In tunnels, busways supply construction equipment and lighting; in railway operations, a side- or top-covered contact rail supplies traction power to rolling stock. This variety affects deconstruction: accessibility, residual voltage, degree of protection, and fixation vary significantly.
Busbars in concrete demolition, strip-out, and specialized deconstruction
During the strip-out of electrical operating rooms, the deconstruction of production lines, or the removal of technical tunnel equipment, busbars are often enclosed by concrete, masonry, or housings. Concrete pulverizers are suitable for selectively removing reinforced concrete to expose bars and supports without generating unnecessary vibration. Rock and concrete hydraulic wedge splitters enable precise, low-vibration joints in foundations and cable ducts, which facilitates the safe release of busbar supports, anchors, and brackets. After safely isolating and verifying absence of voltage, metal housings, cover plates, and fasteners can be separated with hydraulic shears such as steel shears, combination shears, or multi cutters; for large sheet-steel housings, depending on plate thickness, a cutting torch may also be considered. Hydraulic power packs supply the tools with the required energy, which is a logistical advantage in confined or shielded areas.
Exposure without damaging the conductor
When removing material around busways, housing deformation and concealed tap-offs must be avoided. Selective nibbling with concrete pulverizers helps minimize vibration and sparking. In areas with sensitive electronics or potential residual energies, low-vibration splitting takes priority.
Cutting and recovery
After documented de-energization, busbar sections are separated in a controlled cutting sequence, shored, and recovered in an orderly manner. Conductor elements made of copper/aluminum should be cleanly separated due to material value; anchoring bolts made of steel are removed with suitable shears or by localized splitting.
Safety and work preparation
Work on busbars requires a strictly planned approach. Measures to prevent electrical hazards, fire and arc-flash risks must be observed. Processes follow applicable regulations and manufacturer instructions, are adapted to the project, and are documented.
- Review documentation: wiring diagrams, routing, tap-off points, protection concepts.
- Define, cordon off, and mark the work area; designate responsible qualified personnel.
- Properly isolate and de-energize systems, secure against re-energization, and professionally verify absence of voltage.
- Update the hazard analysis: arc flash, residual charges, energy feeds from auxiliary systems (e.g., emergency power).
- Consider fire and explosion protection; provide extinguishing agents and shielding.
- Mechanical securing: shoring, load distribution, install catching devices.
- Clearly regulate communication and permits between electrical and deconstruction teams.
Cutting and dismantling techniques in detail
The choice of technique depends on degree of protection, material thickness, installation location, and available space. The goal is reliable, clean separation with minimal secondary damage.
Copper and aluminum bars
Hydraulic shears allow burr-minimized cuts without thermal influence. For aluminum, pay attention to coatings; for copper, ensure controlled handling of heavy segments. Chip and spark formation should be avoided wherever possible.
Enclosed busway systems
Covers are opened section by section, tap-offs are labeled and dismantled. Connector locations can be identified by their clamping pattern. After releasing the housing hangers, duct sections can be segmented and recovered; for cast-in penetrations, targeted pre-splitting of the masonry helps.
Contact rail in tunnels or track areas
Dismantling is carried out in close coordination with rail engineering stakeholders. Covers, insulators, and supports are removed in a defined sequence. Tunnels often add limited cross-section reserves and tight radii; low-vibration methods reduce impacts on the structure.
Planning in existing structures: structural analysis, fire protection, and coordination
Busbars are often integrated into fire-protected shafts or routes. During deconstruction, fire stops, penetrations, and fire collars must be considered. The structural capacity and reserves of the fixings determine permissible segmentation. Coordination between qualified electrical personnel and the deconstruction team is central so that exposure, cutting, and recovery interlock seamlessly.
Typical findings and risks in deconstruction
Corroded supports, overheated contact points, deformed housings, and incompletely documented tap-offs are common. Particularly critical are concealed feeds, parallel systems, or retrofitted loads. These points must be specifically verified before beginning mechanical work. Controlled removal with concrete pulverizers and the targeted use of splitting wedges help prevent unforeseeable movement.
Environmental and disposal aspects
Professional material separation increases the recycling rate: copper and aluminum are collected separately, steels from housings and supports are separated, insulating materials and seals are disposed of accordingly. Clean cuts with hydraulic tools facilitate transport and reduce rework.
Busbars in tunnel construction and special deployments
In tunnel construction, temporary busways supply machines, lighting, and ventilation. Deconstruction requires short shutdown windows, low emissions, and high process reliability. Low-vibration methods, such as splitting of embeddings and selective reduction with concrete pulverizers, reduce risks to the structure. In special deployments—such as after faults or during time-critical conversions—clear interface coordination and redundant securing are particularly important.
Documentation and quality assurance
All steps—from the de-energization log to the marking of tap-offs through to segmentation—are documented in a traceable manner. Visual inspections for arc traces, loose connectors, or damaged insulation provide clues to suitable dismantling points. The orderly staging of recovered sections supports verification and recycling.