Introduction and Maintenance Intervals
Periodic inspections and maintenance are essential to ob-
tain safe and reliable operation of the circuit breaker as
well as the switchgear.
When circuit breakers and/or the switchgear are operated
under “Usual Service Conditions”, maintenance and lu-
brication is recommended at ten year intervals or at the
number of operations indicated in Table 2. “Usual” and
“Unusual” service conditions for Medium Voltage Metal-
Clad Switchgear are defined in ANSI C37.20.2, section 8.1.
Generally, “usual service conditions” are defined as an en-
vironment in which the equipment is not exposed to ex-
cessive dust, acid fumes, damaging chemicals, salt air,
rapid or frequent changes in temperature, vibration, high
humidity, and extremes of temperature.
The definition of “usual service conditions” is subject to a
variety of interpretations. Because of this, you are best
served by adjusting maintenance and lubrication intervals
based on your experience with the equipment in the ac-
tual service environment.
Regardless of the length of the maintenance and lubrica-
tion interval, Siemens recommends that circuit breakers
and switchgear should be inspected and exercised annu-
ally.
Recommended Maintenance and Lubrication
Periodic maintenance and lubrication should include all
the tasks shown in Table 1. Recommended procedures
for each of the listed tasks are provided in this section of
the manual.
The list of tasks in Table 1 does not represent an exhaus-
tive survey of maintenance steps necessary to ensure safe
operation of the equipment. Particular applications may
require further procedures. Should further information be
desired or should particular problems arise which are not
covered sufficiently for the Purchaser’s purposes, the mat-
ter should be referred to the local Siemens sales office.
Removal from Switchgear
Prior to performing any inspection or maintenance checks
or tests, the circuit breaker must be removed from the
switchgear. The Installation and Initial Functional Tests
section describes the removal procedure in detail. Princi-
pal steps are repeated here for information and guidance,
but without the details of the preceding section.
Maintenance
Failure to properly maintain the equipment could result in
death, serious injury or product failure, and can prevent
successful functioning of connected apparatus.
Instructions should be carefully reviewed, understood, and
followed.
The maintenance tasks in Table 1 must be performed regu-
larly.
The use of unauthorized parts in the repair of the
equipment, or tampering by unqualified personnel will
result in dangerous conditions which will cause death,
serious injury or equipment damage.
Follow all safety instructions contained herein.
10
Hazardous voltages and high-speed
moving parts.
Will cause death, personal injury, and
property damage.
De-energize before working on this equip-
ment.
Read instruction manuals, observe safety in-
structions, and limit use to qualified person-
nel.
Table 1: Maintenance Tasks
• Checks of the primary power path
• Cleanliness check
• Primary disconnect contact cleanliness
and lubrication
• Fastener check
• Wiring and terminals check
• Secondary disconnect check
• Automatic spring charging interlock system check
• Electrical close and trip check
• High potential test
• Insulation test
• Inspection and cleaning of insulation
• Functional tests
• Interlock mechanism cleanliness and lubrication
• MOC Actuator System inspection and lubrication
• Electrical control checks
• Circuit Breaker Operator tasks as detailed
in manual SGIM-9918 (3AH) or SG-3398 (3AF)