
5.MATTERS COMMON TO BOTH LCD-MOUNTED TYPE AND STAND-ALONE TYPE (HARDWARE) B-63945EN/02
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(2) Method of grounding to a near plate
Units
PE
Connection line A
Connection line B
Connection line for grounding
Connection line for protective earth (PE)
Notes on ground system wiring
• The grounding resistance of the protective earth (PE) must be
100 ohms or less (class-D grounding).
• The connection cable for the protective earth (PE) needs to have
a cross-sectional area sufficient for flowing an accidental current
that flows to the protective earth (PE) when an accident such as
a short circuit occurs. (In general, a cross-sectional area equal to
or greater than that of the AC power line is required.)
• As a connection cable for the protective earth (PE), use a cable
integrated with an AC power line so that power is not fed when
the ground wire is disconnected.
• A line for connecting a unit to a near plate (line A in the figure
above) must be connected to the plate along the shortest path,
and its cross-sectional area must satisfy the IEC condition
described below. If the input current is limited by a circuit
breaker, however, satisfaction of the current capacity of the
circuit breaker is sufficient. If a cross-sectional area is specified
in the manual of each unit, observe the specified value.
• For plate-to-plate connection, connect the metal plate to which
the PE is connected with the metal plate to which units are
connected, by using connection line B (as shown above). In this
case, the thickness of the cable is determined by the AC input
current capacity of each unit connected to the plate. If a
cross-sectional area is specified in the manual of each unit,
observe the specified value. If no cross-sectional area is specified,
follow the table below. If the table indicates a thickness greater
than the cross-sectional area of the connection cable for the
protective earth (PE), however, use the cross-sectional area of the
connection cable for the protective earth (PE).