Siemens SENTRON 3VL160X System Manual page 128

Service and maintenance
10.2 Troubleshooting
Circuit breaker status
Mechanical and High humidity
electrical functions:
Corrosion
Function of the internal
accessories
128
Causes of faults
The molded case circuit breakers must not be used in environments
with high humidity since this can cause dielectric and insulation
problems. In such environments, appropriate measures need to be
taken, such as placing the circuit breaker in an enclosure.
The molded case circuit breakers are not designed to be used in
aggressive environments.
In such environments, the circuit breaker should be installed in a
housing.
Determine what type of internal accessories are installed. Remove the
molded case circuit breaker cover and determine the type of
accessories using the circuit breaker order number. Then check for
correct functioning.
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Corrective action
Undervoltage release:
Ensure the correct voltage is connected to the undervoltage
release since otherwise, the circuit breaker cannot be tripped.
Shunt release:
Ensure the voltage is not applied to the shunt release since this can
also prevent the circuit breaker from tripping.
Auxiliary and alarm switches:
The auxiliary and alarm switches do not have any effect on the
protection function of the molded case circuit breaker.
3VL IEC molded case circuit breakers
System Manual, 11/2013, 110 0110 - 02 DS 03