Mitsubishi Electric C Series Handling And Maintenance page 42

(5) Earth leakage relay
1Mounting
1. Mount the earth leakage relay and the ZCT unit separately. Refer to the
catalog for mounting dimension.
2. With the relay of interchangeable type, the relay unit and the ZCT unit
can be combined freely.
For the relay of combination type, be sure to combine the relay unit and
the ACT unit of the same manufacturing number.
Hole diameter of ZCT (mm)
Series
15 30 40 60 80 100 600~2000A
NV-ZBA
NV-ZSA
Interchangeable type
NV-ZHA
NV-ZLA
Combination type
NV-ZU
3. To avoid influence of outside magnetic field, mount the relay and the
ZCT at least 10cm off the conductors which a large current of over sev-
eral thousands ampere flows.
2Connection
1. For single phase three-wise system
and 3 phase 4-wire system, be sure
to pass the three or four wires includ-
ing the neutral wire through ZCT.
(Pass the wire intended to conduct
load current throught ZCT.)
2. Where the line include a wire dedi-
cated to grounding, refrain from
passing the earth wire through ZCT.
(Don't pass the wire not intended for
conducting load current through
ZCT.)
3. Bundle the wires passed through
ZCT with clamp bands, for example,
as they may apply mechanical stress
to the ZCT when large current over
the rated overcurrent strength flows
at a short-circuit failure and others.
7. Where the relay unit is connected to the ZCT unit, take the following
procedure.
Kind of lead wire used vs. sensitivity
Sensitivity
1m
30mA
100 · 200mA
Stranded vinyl coated wire
500mA and more
of 0.5 to 2mm
Notes 1. Number of turns of wire stranding is about 40turns/m.
2. Where single core shield wire is used, connect the core wire and
the shield wire in the right way acdording to the instruction manual.
Example of NV-ZBA type is shown at the right.
With primary conductor (A)
3200A
Combination
type
—
Pass the neutral wire
also through ZCT
Don't pass the earth wire
through ZCT.
Length of lead wire
1m~3m 3m~7m
Single core shield wire
of 0.5 to 2mm
2
4. Don't bend sharply the wires passed
through ZCT near the ZCT. When a
primary conductor of over 300A is
passed through, keep 30cm or more
straight at one side.
5. Refrain from grounding the lead wire
of the ZCT.
6. Make sure that the setting is free
from any error as sensitivity current
is switchable with some models.
Example of single core shield connection
(NV-ZBA type)
2
0
Conductor
Keep off at
least 10cm.
Combination type is
the same serial number.
Keep off at
least 10cm.
0.2
0.5
1A
To ZCT
Shield wire
Core wire
Sensitivity 30mA
Test button Reset button
Leakage indicator
200 Voltage (V)
100
40