Siemens NXAIR - Key-Operated Interlocks for the Busbar Earthing Switch

Key-operated interlocks
368 NXAIR / ≤ 40 kA 110-0134.9 / 14
25.2 Key-operated interlocks for the busbar earthing switch
Function and design
Key-operated interlocks are available for circuit-breaker and disconnecting panels. Access to the key of any
interlock is given with closed door to low-voltage compartment.
Key-operated interlocks allow interlocking or releasing the following operating functions:
• If the busbar earthing switch is in OPEN position, switching it to CLOSED position can be interlocked
by turning and removing the associated key.
• If the busbar earthing switch is in CLOSED position, switching it to OPEN position can be interlocked
by turning and removing the associated key.
The interlocked functions can be released again by reinserting the associated key, and subsequently turning
it in opposite direction.
For customization, the interlocking options are available individually. In case of two interlocks, removing both
keys simultaneously is not possible because the busbar earthing switch must always be either in CLOSED
position or OPEN position.
(1)
Key release:
only when busbar
earthing switch is in
OPEN position
(2)
Key release:
only when busbar
earthing switch is in
CLOSED position
Fig. 667: Door to low-voltage compartment with key-operated interlocks
2
2
1
2