Patent ID: 7679023

Claim:
A switchgear having interrupters wherein at least two moving contacts are capable of being opened and closed with respect to respective fixed contacts, which comprises a non-earthed metal vacuum chamber enclosing the interrupters therein, a connection conductor for connecting the moving contacts, an operating rod connected to the connecting conductor by means of an insulator and protruding from the non-earthed metal vacuum chamber, a sealing means for sealing the protrusion of the operating rod at the non-earthed metal vacuum chamber, circuit terminals protruding from the non-earthed metal vacuum chamber, an insulating mold covering an outer periphery of the non-earthed metal vacuum chamber, an earth layer surrounding an outer periphery of the insulating mold, and a first potential control means, connected to an intermediate point between one of the circuit terminals and the non-earthed metal vacuum chamber, for controlling the potential of the non-earthed metal vacuum chamber.