CONNECTION AND TERMINATIONS OF METAL CLAD SWITCHGEARS BASIC INFORMATION

Bus connections
When the MC switchgear consists of several shipping sections, the main bus is necessarily disconnected before shipping. The main bus should be reconnected, with particular attention paid to the cleanliness of and pressure between the contact surfaces.

It is essential that the connections be securely bolted because the conductivity of the joints is dependent on the applied pressure. Refer to the manufacturer’s torque recommendations and any other special instructions.
Cable connections
Before the cable connections are made, the phasing of each cable should be determined in accordance with the connection diagram, and the cables should be tagged accordingly. The cable manufacturer’s instructions should be followed in forming cable terminations and during the installation of the cable.

It is essential that the connections be clean and torqued to manufacturer’s recommendations since the conductivity of the joints is proportional to the applied pressure. The terminating devices (where required) should be installed pursuant to the terminator manufacturer’s instructions.
Control connections
Control wires between shipping sections should be reconnected as marked by the manufacturer. Connections that are to be connected to terminals in apparatuses remote from the switchgear should be checked carefully against the connection diagram.

In making connections to terminals, care should be exercised to ensure that the connections are made properly.
Grounding
Sections of ground bus previously disconnected at shipping sections must be reconnected when the units are installed. It should be ensured that all secondary wiring is connected to the switchgear ground bus as indicated on the drawings.

The ground bus should be connected to the system ground with as direct a connection as possible and should not be run in metal conduit unless the conduit is adequately bonded to the circuit. The grounding conductor should be capable of carrying the maximum line-to-ground short-circuit current for the duration of a fault.

A reliable ground connection is necessary for every switchgear installation. It should be of sufficient capacity to handle any abnormal condition that might occur in the system and should be independent of the grounds used for other apparatuses.

A permanent low-resistance ground is essential for adequate protection and safety.

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