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IZM32 / IN32 low voltage air circuit breaker
MN013017EN May 2022 www.eaton.com
Section 7: Inspection and maintenance
Section 7: Inspection and maintenance
7-1 General
WARNING
Failure to inspect, clean, and maintain circuit breakers
can reduce equipment life or cause the equipment not
to operate properly under fault conditions. This could
result in equipment damage, bodily injury, or even
death.
CAUTION
Inspection and maintenance procedures should be carried
out only by personnel familiar with the hazards associated
with working on power circuit breakers. Additionally, they
should become familiar with the specifics associated with
type magnum ds circuit breakers as presented in this
instruction booklet.
IZM32 circuit breakers are “top of the line” equipment.
This means that they are manufactured under a high
degree of quality control, with the best available materials,
and with a high degree of tooling for accuracy and parts
interchangeability. Design tests and actual installation
experience show them to have durability well beyond
minimum standards requirements. However, because
of the variability of application conditions and the great
dependence placed upon these circuit breakers for
protection and the assurance of service continuity,
inspection and maintenance activities should take place on a
regularly scheduled basis.
Because maintenance of these circuit breakers consists
mainly of keeping them clean, the frequency of scheduled
inspection and maintenance depends to some degree on
the cleanliness of the surroundings. Cleaning and preventive
measures are a part of any good maintenance program.
Plant operating and local conditions can vary to such an
extent that the actual schedule should be tailored to the
conditions. When the equipment is subject to a clean and
dry environment, cleaning is not required as frequently as
when the environment is humid with a significant amount of
dust and other foreign matter.
It is recommended that maintenance record sheets
be completed for the equipment. Careful and accurate
documentation of all maintenance activities provides a
valuable historical reference on equipment condition over
time.
7-2 General cleaning recommendations
Circuit breaker cleaning activities should be a part of an
overall activity that includes the assembly in which the
circuit breaker is installed. Loose dust and dirt can be
removed from external surfaces using an industrial quality
vacuum cleaner and/or lint-free cloth. Unless otherwise
indicated, never use high-pressure blowing air, because
dirt or foreign objects can be driven into areas, such as the
breaker mechanism, where additional friction sources could
create problems. Never use a wire brush to clean any part
of the circuit breaker.
7-3 When to inspect
Do not wait for specific scheduled periods to visually
inspect the equipment, if there are earlier opportunities.
If possible, make a visual inspection each time a circuit
breaker compartment door is opened, and especially when
a circuit breaker is withdrawn on its compartment extension
rails. This preventive measure could help to avoid future
problems. Industry standards for this type of equipment
recommend a general inspection and lubrication after the
number of operations listed in Table 8-1 of this section.
This should also be conducted at the end of the first six
months of service, if the number of operations has not been
reached.
Table 7.1 Inspection frequency
After the first inspection, inspect at least once a year. If
these recommended inspections show no maintenance
requirements, the period may be extended to a more
economical point. Conversely, if the recommended
inspection shows, for instance, a heavy accumulation of
dirt or other foreign matter that might cause mechanical,
insulation, or other electrical damage, the inspection and
maintenance interval should be decreased.
7-4 What to inspect
What to inspect and to what extent is dictated by the nature
of the maintenance function. Routine inspections require
one type of observation. Inspections following a known
high-level fault require more detailed inspections.
A drawout type circuit breaker should first be withdrawn
from its compartment onto the compartment’s extension
rails. When the inspection is complete, the circuit breaker
can be levered to the TEST position to check the electrical
operations of the circuit breaker. During the levering-out and
levering-in of the circuit breaker, be aware for any signs that
would indicate that this process is not working properly.
During the inspection of fixed type circuit breakers, bus
systems supplying the fixed circuit breakers should be
de-energized for convenience and safety.
For functional testing of the trip unit, refer to the separate
detailed instruction booklet dedicated to the trip unit.
Once the circuit breaker has been cleaned as specified in
Section 7-2, inspect it for any signs of damage, missing or
loose parts, and unusual wear. Be especially alert for foreign
matter that must be removed. On drawout circuit breakers,
inspect the primary disconnect finger clusters for signs of
wear and erosion. Make appropriate corrections to anything
found out of order.
Breaker Frame Size
Interval (Breaker Cycles)
800 A and below
1750
800 A - 3000 A
500
3000 A and above
250
Breaker cycle = one no load open/close operation.
NOTICE
WARNING
