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Metal-Clad vs Metal-Enclosed

The selection of the type of switchgear to be used in a project is a tedious job. Design engineers need to know what are the requirements of the project to be able to specify what type of switchgear is needed. In a project with a highly skilled personnel and requires monitoring, a metal-clad switchgear is recommended.

Metal-Clad vs Metal-Enclosed
  Metal-clad Metal-enclosed
Main Interrupting Device
Drawout circuit breakers Fixed Switch and fuse combination
Bus works
Insulated Bare
Live Parts
No exposed live parts even when cover is removed Exposed live parts when cover is removed
Cost
High Low
Maintenance
High Low
Auxiliary Power
Yes No
Single Phasing Protection
Standard Options
Communication Interface
Available None

Additional features of metal-clad switchgear are:

  • The main interrupting device is removable and arranged with a mechanism for moving it physically between connected and disconnected positions. It is equipped with self-aligning and self-coupling primary and secondary disconnecting devices.
  • The interrupting devices, buses, voltage transformers, and control power transformers, are completely enclosed by grounded metal barriers, which have no intentional openings between compartments. A metal barrier in front of the interrupting device ensures that when, in the connecting position, no live parts are exposed by the opening of an enclosure door.
  • All live parts are enclosed within grounded metal compartments.
  • Automatic grounded metal shutters cover primary circuit elements when the removable element is in the disconnected, test, or removed position.
  • Primary bus conductors and connections are covered with track-resistant insulating material throughout.
  • Mechanical interlocks are provided to maintain a proper and safe operating sequence and to ensure matching ampacities between circuit breaker and cell.
  • Grounded metal barriers isolate and ground instruments, meters, relays, secondary control devices, and their wiring from all primary circuit elements. If a short circuit or fault occurs, all damage is contained within the metal-clad enclosure.
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