Maintenance And Inspection; Initial Inspection - Mitsubishi Electric C Series Handling And Maintenance

4. Maintenance and inspection

Any maintenance/inspection shall be performed by the personnel having expertise concerned.
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Note that there exists the risk of electrical shock.
Any maintenance/inspection shall be performed after cutting off the master circuit-breaker
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and making sure that there is no current flowing.
Note that there exists the risk of electrical shock.
(1) If maintenance and/or inspection should be carried out without cutting off the power supply
in an unavoidable cases, wear rubber gloves and insulated boots laying rubber mat on the
floor. Use insulated tools and instruments only. An access to the live parts is necessary in
this maintenance and inspection work, when workers' full attention should be paid to the
insulation of human body from the live parts.
Any normal opening/closing may be done safely because the live parts are covered with
insulated moulded case or the like.
(2) In the event of measurement of sensitivity current and operate time of the ELCB mounted
on hot line, de-energize first and then wire before proceeding to the measurement as far as
possible. If, from sheer necessity, the measurement should be made under electrified con-
dition, full care should be taken of the safety.

4.1 Initial inspection

The following items shall be checked when electrification is initiated with MCCB and ELCB installed:
Type
1. Are there any excessive screws, machining
chips, cut pieces of electric wire and other con-
ductors around the terminals?
2. Is there any crack nor breakage of cover and/or
base?
3. Any dew condensation on the cover, base
Common
and/or terminals?
4. The insulation resistance to be measured by
500V insulation resistance tester.
5. Are the conductive connections tightened firmly?
6. Is the rated voltage of ELCB the same as that of
circuit voltage?
ELCB
7. Apply voltage and depress the test button to
check the operation.
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CAUTION
Inspection item Criterion
There must never be such foreign
matters remaining.
No crack/breakage allowed
No dewing allowed nor traces of
condensation allowed.
Measurement should be 5MΩ or
higher.
The tightening torque should be as
prescribed.
Should be the same.
Leak trip state should come out
and reclosing possible.
Remarks
For ELCB, refer to the "Attention."