Withdrawable Switchgear
Product Overview
Withdrawable Switchgear is a low-voltage metal-enclosed switchgear assembly designed for power distribution, circuit protection, measurement and control in industrial, commercial and critical power systems.
Unlike fixed type switchgear, withdrawable switchgear uses movable functional units or circuit-breaker drawers that can be moved between defined operating positions. This configuration allows the electrical connection, testing and isolation status of individual functional units to be managed without removing the complete switchgear assembly from service.
The switchgear can integrate air circuit breakers (ACBs), molded case circuit breakers (MCCBs), busbars, protection devices, metering components, control circuits and communication modules according to the project electrical design.
Construction & Configuration
Sectionalized Cabinet Framework
The switchgear enclosure is assembled from formed steel panels and structural profiles. The supplied configuration uses 2.0 mm Al-Zn coated steel sheets, with alternative structural configurations available according to project requirements. The cabinet is arranged as a modular multi-panel system to accommodate main busbars, distribution busbars, functional units, cable connections and low-voltage control components.
Functional Unit / Drawer System
The defining feature of withdrawable switchgear is its movable functional-unit architecture. Depending on the selected configuration, drawers can be arranged in different modular heights to accommodate feeder circuits, motor control circuits or other low-voltage functional units. Each functional unit incorporates a mechanical operating and interlocking mechanism associated with its circuit breaker or switch-disconnector. The mechanism controls movement between the defined operating positions and helps prevent movement under prohibited operating conditions.
Operating Positions
The withdrawable mechanism can provide defined positions such as:
Service / Connected Position - the main circuit is connected to the switchgear busbar system.
Test Position - the main power connection is isolated while designated control and auxiliary functions can remain available for testing, where supported by the configuration.
Disconnected / Isolated Position - the functional unit is separated from the main power circuit.
The exact operating positions and interlocking sequence depend on the selected functional-unit design.
Busbar System
Main and distribution busbars are manufactured from electrolytic copper according to the specified current rating and electrical configuration. The busbar arrangement, conductor size, connection points and support system are determined according to the approved electrical design and applicable technical requirements.
Internal Separation
The switchgear can be configured to Form 4b or other specified forms of separation, depending on the project requirements. Internal barriers and partitions separate the main busbar area, functional units and outgoing cable or terminal areas according to the selected construction.
Low-Voltage Control Section
Control components, protection relays, metering devices, terminal blocks, auxiliary circuits and communication components can be arranged within designated low-voltage sections. The control configuration is coordinated with the selected circuit breakers and the customer's protection and automation requirements.
Technical Specifications
|
Parameter |
Technical Specification |
|
Product Type |
Low Voltage Withdrawable Switchgear |
|
Rated Operational Voltage (Ue) |
Up to 690 V AC, 50/60 Hz |
|
Rated Insulation Voltage (Ui) |
Up to 1000 V AC |
|
Rated Impulse Withstand Voltage (Uimp) |
Up to 12 kV, according to configuration |
|
Main Busbar Rated Current (In) |
Up to 6300 A |
|
Distribution Busbar Rated Current |
Up to 1600 A |
|
Rated Short-Time Withstand Current (Icw) |
Up to 100 kA / 1 s or 50 kA / 3 s, depending on configuration |
|
Rated Peak Withstand Current (Ipk) |
Up to 220 kA, depending on configuration |
|
Enclosure Protection |
IP30 / IP40 standard configurations; higher IP ratings available where applicable |
|
Internal Separation |
Form 4b / Form 3b, according to configuration |
|
Main Components |
ACBs, MCCBs, busbars, protection, metering and control components |
|
Functional Unit |
Withdrawable drawer / functional unit |
|
Applicable Product Standard |
IEC 61439-1 / IEC 61439-2 |
|
Surface Treatment |
Epoxy-polyester powder coating, according to specified finish |
Key Features
Withdrawable Functional Units: Individual functional units can be moved between defined operating positions according to the switchgear configuration.
Service / Test / Disconnected Positions: Defined mechanical positions support different connection, testing and isolation states.
Mechanical Interlocking: Interlocking mechanisms coordinate drawer movement with the associated circuit breaker or switch-disconnector operating state.
Form 4b Configuration: Internal separation can be configured to Form 4b where required by the project specification.
Modular Internal Arrangement: Main busbars, distribution busbars, functional units, cable areas and control components are arranged within a sectionalized cabinet.
Flexible Feeder Configuration: Functional units can be configured for incoming feeders, outgoing feeders, motor circuits and other low-voltage distribution requirements.
Protection and Monitoring Integration: ACBs, MCCBs, electronic trip units, meters, motor-management components and communication devices can be incorporated according to the electrical design.
Multi-Panel System: Individual vertical sections can be combined into a complete switchgear lineup according to the required number and arrangement of circuits.
Applications
Data Centers & Critical Power Systems:
Withdrawable switchgear can be used for low-voltage main distribution and feeder circuits downstream of transformers or other low-voltage power sources. The withdrawable configuration is suitable where individual functional units require defined operating and isolation positions.
Industrial Manufacturing & Motor Control:
The switchgear can integrate feeder protection and motor-related circuits for manufacturing plants and process facilities. Functional-unit arrangements can be configured according to the required feeder and motor circuit schedule.
Oil, Gas & Process Facilities:
Low-voltage distribution and motor control applications can be configured with circuit protection, measurement and control functions according to the electrical and automation requirements of the facility.
Water & Wastewater Treatment:
Withdrawable switchgear can be used for pump, motor and auxiliary power distribution circuits where multiple functional units are integrated into a centralized low-voltage switchboard.
Heavy Manufacturing:
High-current busbar configurations and multiple withdrawable functional units can be applied to industrial distribution systems with multiple feeder and motor circuits, subject to the required electrical ratings.
Manufacturing & Quality Control
Production covers sheet-metal fabrication, structural assembly, busbar processing, functional-unit assembly, electrical wiring and final inspection.
Sheet-Metal Fabrication:
CNC punching, laser cutting and bending processes are used for cabinet panels and structural components. Dimensional requirements are controlled according to approved manufacturing drawings and inspection specifications.
Busbar Processing:
Copper busbars are cut, punched and bent according to the required electrical configuration before installation into the switchgear. Connection surfaces and joint assembly are inspected according to the applicable production and electrical requirements.
Functional-Unit Assembly:
Withdrawable drawers are assembled with their circuit breakers or switch-disconnectors, operating mechanisms, auxiliary contacts and control connections. The operating mechanism and interlocking functions are checked during assembly and final inspection.
Surface Treatment:
Cabinet components are processed according to the specified surface-treatment system before final assembly. The applicable coating specification depends on the project requirements and selected cabinet configuration.
Customization & Project Support
Withdrawable Switchgear can be configured according to project-specific electrical, mechanical and installation requirements.
Customization can include rated operational voltage, rated current, main/distribution busbar ratings, short-time withstand current, incoming/outgoing arrangement, ACB/MCCB selection, protection/trip-unit configuration, metering devices, motor-management components, communication interfaces, and auxiliary control circuits.
The withdrawable system can be arranged according to the required feeder schedule, including functional-unit size, drawer arrangement, circuit-breaker type, Service/Test/Disconnected positions, auxiliary contacts, control wiring, and mechanical interlocking requirements.
Project-specific requirements can include cabinet dimensions, panel arrangement, cable entry direction, internal separation, enclosure protection, busbar position, low-voltage compartment arrangement, and site installation requirements.
Engineering coordination can be based on single-line diagrams (SLDs), load schedules, feeder schedules, electrical specifications, protection requirements, component lists, general arrangement drawings, and installation information. Where applicable, the project documentation package can include GA drawings, electrical schematics, wiring diagrams, equipment lists and applicable test documentation.
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