Power Supply, Grounding, And Connection - Siemens SENTRON 3WL10 Series Manual

Application planning

4.2 Power supply, grounding, and connection

4.2 Power supply, grounding, and connection
The 3WL10 air circuit breaker can be powered through the main circuit connection terminals.
The electronic trip unit is therefore self-powered in all phases via internal current
transformers in compliance with the standard to ensure its protection function without
additional conditions in the event of a fault.
Even if, with open main contacts, the electronic components ETU, metering function, and
CB bus modules are operated or protection functions, such as MCR or G_ret are activated
(e.g. for communication of circuit breaker status, applied line voltage signal etc.), these
components can be externally powered via the auxiliary voltage.
The external power supply can be achieved in two ways:
● The Breaker Connect module is mainly used for this and the auxiliary power supply of the
control cabinet can be connected directly to it. The auxiliary power supply is always
necessary for the communication function.
● As a further option, the MF Advanced metering module can be used. If the voltage is
tapped internally on the line side with the contacts open, this can also be used to power
the electronics directly and independently.
If a metering module is present, the voltage taps must be installed on the line side. In the
circuit breaker OPEN position, this also ensures that all relevant information is available.
Cables and busbars and connection methods
The connection bars and cables can be connected directly to the 3WL10 air circuit breaker.
The cables and busbars can be made of the following materials:
● Copper
● Silver-plated copper
● Zink-plated aluminum if the main distribution system is made of aluminum.
The following connection methods can be used (see also Chapter Accessories for
connection and insulation (Page 71)):
● For fixed breakers:
– Front terminals for busbars, cable lugs, and cables
– Rear terminals for busbars, cable lugs, and cables
● For withdrawable breakers:
– Front terminals for busbars and cable lugs
– Rear terminals for busbars and cable lugs
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Air circuit breaker 3WL10
Manual, 11/2017, L1V30499596002-01