IB01602007E
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Instruction Bulletin
Effective: June 2003
Page
25
O&M Manual for
Non-Automatic Transfer
Switches (30 – 1200 Amperes)
Section 7: Maintenance
7.1 Introduction
In general, transfer switch equipment
is designed to be relatively mainte-
nance free under normal usage.
However, because of the variability of
application conditions and the impor-
tance placed on dependable operation
by this type of equipment, inspection
and maintenance checks should
be made on a regularly scheduled
basis. Since equipment maintenance
will consist mainly of keeping the
equipment clean, the frequency of
maintenance will depend, to a large
extent, on the cleanliness of the sur-
roundings. If a significant amount
of dust or foreign matter is present,
a more frequent maintenance sched-
ule should be followed.
It is suggested that visual inspections
of the equipment be made on a regular
basis, not just during regularly sched-
uled periods. Always be alert for an
accumulation of dirt in and around the
structure, loose parts and/or hardware,
cracks and/or discoloration to insula-
tion, and damaged or discolored
components.
WARNING
HIGH VOLTAGES ARE PRESENT IN
AND AROUND TRANSFER SWITCH
EQUIPMENT. BEFORE INSPECTING
OR MAINTAINING THIS EQUIP-
MENT, DISCONNECT LINE POWER
FROM THE EQUIPMENT BEING SER-
VICED BY OPENING AND LOCKING
OUT, IF POSSIBLE, THE NEXT HIGH-
EST DISCONNECT DEVICE. FAILURE
TO FOLLOW THIS PROCEDURE
COULD CAUSE PERSONAL INJURY
AND/OR DEATH.
7.2 Procedures
A suggested maintenance procedure to follow is outlined in Table 5.
Table 5. Periodic Maintenance Procedures
Step
Action
A
Make transfer switch equip-
ment safe for inspection and/
or maintenance.
Disconnect line power from equipment being serviced by
opening next highest disconnect device. Make certain that
any accessory control power is switched off by disconnecting
all logic plugs.
B
Inspect structure area for
safety hazards or potential
maintenance problems.
Inspect area, especially where molded case switching
devices are installed, for any safety hazards, including per-
sonnel safety and fire hazards. Exposure to certain chemical
vapors can cause deterioration of electrical connections.
Inspect for accumulated dirt, loose hardware or physical
damage.
Examine primary insulation for evidence of cracking
or overheating. Overheating will show as discoloration,
melting or blistering of conductor insulation, or as pitting
or melting of conductor surfaces due to arcing.
Inspect secondary control connections for damage, and
control wiring for insulation integrity.
C
Inspect molded case
switching devices for dust,
dirt, soot, grease, moisture
or corrosion.
Remove dust, dirt, soot, grease, moisture and corrosion
contamination from the surface of the switching device using
a dry soft lint-free cloth, dry soft bristle brush and vacuum
cleaner. Do not blow debris into circuit breaker or nearby
breaker structure. If contamination is found, look for the
source and fix the problem.
D
Check for material integrity,
uneven wear, discoloration
or loose hardware.
Severe material cracking will require replacement and loose
hardware will need to be tightened.
E
Check terminals and
connectors for looseness or
signs of overheating.
Overheating will show as discoloration, melting or blistering
of conductor insulation.
Connections that do not have signs of looseness or
overheating should not be disturbed.
F
Exercise the molded case
switching devices if they are
not often exercised while in
operation. This will permit
wiping action by the contacts.
If a switching device is used for frequent switching during
normal operation, this step can be disregarded.
G
Return transfer switch
equipment to service.
Make certain all barriers are in place and doors closed.
Re-apply secondary and primary power.
