IB140058EN
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Instructional Booklet
Effective: March 2016
Page
19
O&M Manual for 30-1000 Amperes
Manual Transfer Switch
Section 7: Maintenance
7.1 Introduction
In general, transfer switch equipment is designed to be relatively
maintenance free under normal usage. However, because of the
variability of application conditions and the importance 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 surroundings. If a sig-
nificant amount of dust or foreign matter is present, a more fre-
quent maintenance schedule should be followed.
It is suggested that visual inspections of the equipment be made
on a regular basis, not just during regularly scheduled periods.
Always be alert for an accumulation of dirt in and around the
structure, loose parts and/or hardware, cracks and/or discoloration
to insulation, and damaged or discolored components.
7.2 Procedures
A suggested maintenance procedure is outlined in Table 6.
Table 6. Periodic Maintenance Procedures
WARNING
HIGH VOLTAGES ARE PRESENT IN AND AROUND ATS EQUIPMENT.
BEFORE INSPECTING OR MAINTAINING THIS EQUIPMENT, DISCON-
NECT THE LINE POWER FROM, THEN LOCK OUT, IF POSSIBLE, THE
NEXT HIGHEST DISCONNECT DEVICE. FAILURE TO FOLLOW THIS
PROCEDURE COULD CAUSE SEVERE PERSONAL INJURY AND/OR
DEATH.
STEP
ACTION
a. Make transfer switch equipment 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 personnel safety and fire hazards. Exposure to certain chemical
vapors can cause deterioration of electrical.
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 melt-
ing of conductor surfaces due to arcing.
Inspect secondary control connections for damage, and control wiring for insulation integ-
rity.
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 contamina-
tion 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.
