What is Withdrawable Switchgear?
Withdrawable switchgear (also known as draw-out switchgear) is a type of low and medium voltage electrical switchgear where the main circuit components — such as circuit breakers, contactors, and control units — are mounted on removable drawers or carriages. These drawers can be physically withdrawn from the enclosure for maintenance, inspection, or replacement without shutting down the entire switchboard.
Unlike fixed type switchgear where all components are permanently wired in place, withdrawable switchgear offers a modular “plug-and-play” design. Each functional unit slides into a dedicated compartment in the switchgear panel and connects automatically to the busbar system and control circuits through secondary disconnect contacts.
This design is widely used in critical power distribution applications where uptime and maintenance flexibility are essential — including power plants, petrochemical facilities, data centers, and large industrial complexes.
How Withdrawable Switchgear Works
The core mechanism of withdrawable switchgear is the draw-out chassis. Each circuit breaker or functional unit is mounted on a metal chassis with wheels or slides that allow it to move between three defined positions:
1. Connected Position
In the connected position, both the primary (main power) and secondary (control/auxiliary) contacts are fully engaged. The unit is electrically live and functioning as part of the distribution system.
2. Test Position
In the test position, the primary contacts are disconnected, but the secondary contacts remain engaged. This allows operators to test control and protection functions — such as relay tripping, signaling, and interlocking — without energizing the main circuit.
3. Disconnected / Withdrawn Position
In the disconnected position, both primary and secondary contacts are separated. The drawer can be safely removed from the enclosure for inspection, maintenance, or replacement. Physical shutters automatically cover the live busbar connections inside the compartment for safety.
Types of Withdrawable Switchgear
Withdrawable switchgear is available in several configurations depending on the application and voltage level:
Low Voltage Withdrawable Switchgear (LV)
For systems up to 690V, common LV withdrawable switchgear models include:
- MNS Switchgear — Modular, rated up to 6300A, widely used in power plants and heavy industry
- GCS Switchgear — Rated up to 5000A, designed for power stations and distribution systems
- GCK Switchgear — Compact design rated up to 3150A, ideal for general industry and buildings
Medium Voltage Withdrawable Switchgear (MV)
For systems from 3.6kV to 40.5kV, common MV withdrawable switchgear includes:
- KYN28-12 Switchgear — Metal-clad, rated up to 12kV, the most widely used MV switchgear in China
- KYN61-40.5 Switchgear — Rated up to 40.5kV for higher voltage distribution
Withdrawable vs Fixed Type Switchgear: Key Differences
| Aspect | Withdrawable | Fixed Type |
| Unit Replacement | Hot-swappable — replace without powering down entire panel | Requires full panel shutdown |
| Maintenance | Easy — withdraw the drawer, work safely outside the panel | Difficult — work inside live enclosure |
| Cost | Higher initial investment | More economical |
| Space Efficiency | Better — denser configuration | Good |
| Safety | Higher — physical isolation during maintenance | Standard |
| Best For | Critical processes, continuous operation | Standard distribution, budget-constrained projects |
Benefits of Withdrawable Switchgear
Reduced Downtime
The most significant advantage of withdrawable switchgear is drastically reduced downtime. When a circuit breaker or functional unit fails, the faulty drawer can be withdrawn and replaced with a spare unit in minutes — without shutting down other circuits in the panel. In critical applications like data centers or petrochemical plants, this can save millions in lost production.
Enhanced Safety
Withdrawable designs inherently improve safety. Maintenance personnel can remove the drawer and work on it in a safe, accessible location rather than reaching into a live enclosure. The automatic shutter mechanism also prevents accidental contact with live busbars when a drawer is removed.
Flexibility and Scalability
Modular drawer design allows easy system expansion. Additional functional units can be added by installing new drawers in existing compartments — no need to rewire or reconfigure the entire panel.
Simplified Testing and Commissioning
The test position feature allows complete functional testing of protection relays, meters, and control circuits before the unit is put into service, reducing commissioning time and risk.
Typical Applications
- Power Plants — Auxiliary power distribution, unit auxiliary transformers, motor control centers
- Petrochemical & Refineries — Process control, motor control, critical power distribution
- Data Centers — Critical power distribution requiring maximum uptime
- Mining & Metallurgy — Harsh environment applications with high reliability requirements
- Commercial Buildings — Large-scale main switchboards and distribution panels
- Infrastructure — Airports, hospitals, water treatment facilities
FAQ — Withdrawable Switchgear
What is the difference between withdrawable and fixed switchgear?
Withdrawable switchgear has removable units (drawers) that can be pulled out for maintenance or replacement without shutting down the entire system. Fixed switchgear has all components permanently mounted and wired, requiring a full shutdown for service.
Is withdrawable switchgear more expensive?
Yes, withdrawable switchgear typically costs 20-40% more than fixed type due to the additional mechanical components (drawer mechanisms, secondary contacts, shutters). However, the total cost of ownership is often lower when reduced downtime and easier maintenance are factored in.
What voltage levels are available for withdrawable switchgear?
Withdrawable switchgear is available for both low voltage (up to 690V) and medium voltage (3.6kV to 40.5kV) applications. For higher voltages, fixed type or GIS (Gas Insulated Switchgear) is typically used.
Get a Quote for Withdrawable Switchgear
GOHO manufactures a full range of low and medium voltage withdrawable switchgear, including MNS, GCS, GCK, KYN28-12, and KYN61-40.5 series. All products are designed and tested to IEC standards. Contact our team for a quote or technical consultation.