Siemens NXAIR Operating Instructions Manual page 78

Operating the circuit-breaker panel
Mechanical coding
The low-voltage connections are coded with regard to specific current ratings. In the case of circuit-breaker
panels, the coding comprises also the specific control functions of a panel version.
The 4 coding pins (1) on the low-voltage plug connection prevent plugging on the low-voltage connector of
a panel which is not suitable for the particular withdrawable part.
1
Fig. 125: Low-voltage plug connection
Coding symbols
On the top side of every withdrawable part (2) and on the top side of every low-voltage connector (6) there
are 2 or 3 coding symbols respectively. A withdrawable part may only be inserted in a panel, if the coding
symbols are identical in number and kind with those on the low-voltage connector.
Fig. 126: Coding symbols on low-voltage connector and withdrawable part
The coding symbols characterize the functional properties of a panel version. The leftmost symbol (3)
characterizes the functional properties as regards electromagnetic interlocks.
A second symbol or a combination of two further symbols (4; 5) characterizes the panel version as regards
its current ratings.
In the case of circuit-breaker panels, the second symbol or the combination of two further symbols
characterizes the panel version additionally as regards its specific control functions. Circuit-breaker panels
with basic control functions are equipped with 1 shunt release and no other releases. Basic control functions
are coded by one symbol only. Circuit-breaker panels with extended control functions are equipped with a
second release (a second shunt release / a c.t.-release / an undervoltage release). Extended control
functions are coded by a combination of two symbols.
78
1
2
5
3 4
6
NXAIR / ≤ 40 kA
Top side of
(2)
withdrawable part
Coding symbol for
(3)
electromagnetic interlock
Coding symbol for
current rating
(4)
(circuit-breaker panels:
also for control functions)
Optional:
Coding symbol for
(5) current rating
(circuit-breaker panels:
also for control functions)
Top side of
(6)
low-voltage connector
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