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4. INSPECTION AND FIELD TESTING
MCPs are designed to provide years of almost
maintenance-free operation. The following procedure
describes how to inspect and test an MCP in service.
Inspection
MCPs in service should be inspected periodically. The
inspection should include the following checks (4-1
through 4-7):
BEFORE INSPECTING THE MCP IN AN ELECTRICAL
SYSTEM, MAKE SURE THE MCP IS SWITCHED TO
THE OFF POSITION AND THAT THERE IS NO VOLT-
AGE PRESENT WHERE WORK IS TO BE PER-
FORMED. THE VOLTAGES IN ENERGIZED EQUIP-
MENT CAN CAUSE DEATH OR SEVERE PERSONAL
INJURY.
MAKE SURE THAT CLEANING AGENTS OR SOL-
VENTS USED TO CLEAN THE MCP ARE SUITABLE
FOR THE JOB. SOME COMMERCIAL CLEANING
AGENTS WILL DAMAGE THE NAMEPLATES OR
MOLDED PARTS.
4-1. Remove dust, dirt, soot, grease, or moisture from
the surface of the MCP using a lint-free dry cloth, brush,
or vacuum cleaner. Do not blow debris into MCP. If con-
tamination is found, Iook for the source and eliminate
the problem.
4-2. Switch MCP to ON and OFF several times to be
sure that the mechanical linkages are free and do not
bind. If mechanical linkages are not free, replace MCP.
4-3. With the MCP electrically isolated, switch handle to
the ON position and press the PUSH-TO-TRIP button to
mechanicalIy trip the MCP. Trip, reset, and switch MCP
ON several times. If mechanism does not reset each
time the MCP is tripped, replace the MCP.
4-4. Check base, cover, and operating handle for
cracks, chips, and discoloration. Replace MCPs if
cracks or severe discoloration is found.
4-5. Check terminals and connectors for looseness and
signs of overheating. Overheating shows as discol-
oration, melting, or blistering of conductor insulation, or
as pitting or melting of conductor surfaces due to arcing.
If there is no evidence of overheating or looseness, do
not disturb or tighten the connections. If there is evi-
dence of overheating, terminations should be cleaned or
replaced. Before reenergizing the MCP, all terminations
and cable should be refurbished to the condition when
originally installed.
4-6. Check MCP mounting hardware. Tighten if necessary.
4-7. Check area where MCP is installed for any safety
hazards, including personal safety and fire hazards.
Exposure to certain types of chemicals can cause dete-
rioration of electrical connections.
Field Testing
Any field testing should be done in accordance with
NEMA Standards Publication AB2-1984.
!
WARNING
!
CAUTION
40752-165(1) Effective March 2008
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