Metal-Clad Switchgear

Drawout metal-clad switchgear is designed to provide a reliable source for medium voltage SupplyLevel Inc.. The switchgear assembly consists of individually grounded, compartmentalized heavy-gauge steel structures. Each structure has doors, barriers, and removable access panels to isolate the separate working functions and to provide protection to operating personnel. All of the circuit breakers, instrument and control power transformers, relays, meters, and other components are factory assembled, wired, and tested as an assembly.

Each assembly is custom-designed to the user's specifications. Standard structures and bus configurations are arranged to the customer's specifications. The structures are then combined with the circuit breakers, relays, meters, and other components needed to provide the complete metal-clad switchgear as specified.

ANSI Standard C37.20 defines metal-clad switchgear as follows:
Metal-clad switchgear is metal-enclosed power switchgear characterized by the following necessary features:

1. The main switching and interrupting device is of the removable type arranged with a mechanism for moving it physically between connected and disconnected positions and equipped with self-coupling primary and secondary disconnecting devices.
2. Major parts of the primary circuit, such as the circuit switching or interrupting devices, buses, potential transformers, and control power transformers, are enclosed and separated by grounded metal barriers. Specifically included is an inner barrier in front of or a part of the circuit interrupting device to ensure that no primary circuit components are exposed when the unit door is opened.
3. All live parts are enclosed within grounded metal compartments. Automatic shutters prevent exposure of primary circuit elements when the removable element is in the disconnected, test, or removed position.
4. Primary bus connectors and connections are covered with insulating material throughout.
5. Mechanical interlocks are provided to ensure a proper and safe operating sequence.
6. Instruments, meters, relays, secondary control devices and their wiring are isolated by grounded metal barriers from all primary circuit elements with the exception of short lengths of wire such as at instrument transformer terminals.
7. The door through which the circuit interrupting device is inserted into the housing may serve as an instrument or relay panel and may also provide access to a secondary or control compartment within the housing.

Note: Auxiliary units may be required for mounting devices or for use as bus transition."