Specifications

Transducers
144
Model name
T-51LG
Number of units
10
Auxiliary power supply
110VAC
Combined ZCT
ZT15B
Output
Voltage or current
4-20mA
Input
Current
15mA
Specify the primary
side current of the ZCT.
: Rated input current value selection method
Reference
zMonitoring leakage current due to insulation degradation of loaded equipment
Install the ZCT in the immediate vicinity of the loaded equipment.
The sensitivity current of an earth leakage circuit breaker is determined as indicated below. Select an input current value
that is 1 to 1.5 times the value indicated below.
Example: Selecting a sensitivity current according to the electrical shock protection of an earth-leakage circuit breaker.
xMonitoring leakage current in a long cable wiring
Even if the insulation resistance (meg) is normal, floating capacitance is present between the electric line and earth, and some
leakage current flows constantly. This must be taken into account when selecting the input current value. An example of a 3-
phase, 3-wire 200V circuit is shown in Table 1.
The rated current value is the sum of the value determined in Table 1 and the value determined in Reference z above.
Large-size motorized equipment
Large-size supply and drainage pump
Outdoor plant electric equipment
General electric equipment
(such as for control centers)
Room air conditioner, chilling unit, electric water
heater, thermal storage heater, large-size
refrigerator, factory fan, electric washing machine,
electric water boiler, electric dishwasher, well
pump, supply and drainage pump, freezer
showcase, electric drier, electric brooder, electric
floor heater, automatic vending machine, general
electric motor appliance, easily accessible lighting
duct wiring, under-carpet duct wiring
When using metal-encased,
low-voltage equipment that
exceeds 60V
Earth resistance
value:
500Ω or less
Earth resistance
value:
500Ω or less
Earth resistance
value:
250Ω or less
Earth resistance
value:
100Ω or less
30mA
or
15MA
100mA
200mA
500mA
0.60mA/km
0.66
0.72
0.81
0.91
1.02
1.14
1.25
1.46
1.52
1.71
A 4m or more
 1st floor roof wiring of a wooden building
 Wiring for 2nd floor or higher of a wooden building
Aerial wiring
(excluding
C
or
D
)
B 10cm or more
 Wiring inside a reinforced concrete line
 Vinyl pipe wiring or exposed wiring
inside a steel beam
(excluding
C
or
D
)
C 1.5mm or more
 Vinyl pipe-embedded work
 Vinyl pipe work in close
contact with steel beam
inside a steel building
D Close contact
Metal pipe wiring work
Metal duct work
8
14
22
38
50
80
100
150
250
325
500
mm
2
or less
1.29mA/km
1.44
1.55
1.75
1.97
2.21
2.46
2.72
3.16
3.29
3.69
19.9mA/km
22.1
23.9
26.9
30.3
34.0
37.9
41.8
48.6
50.7
56.8
100mA/km
110
120
135
152
170
189
209
243
253
284
Cable
size
Distance
from earth
portion
*1 With respect to the values shown above, the value for rubber-insulated cable (RB) is approximately 70% and that for a
three-core 600V crosslinked polyethylene insulated cable (CV) is approximately 50%.
*2 With respect to the values shown above, the value in the case of 50HZ is 84%.
*3 For the leakage current of other cables, multiply the value in Table 1 by a factor of 2.
*4 For the length of the cable run, add all parts beyond the point of installation of the ZCT.
1-phase
100V cable run
1-phase 3-wire
200V cable run
3-phase 415 cable run
(Y connection)
0.3
0.3
0.7
Type of cable wiring Factor
Table 2
Leakage current conversion table
Table 1 Leakage currents when 1km of 600V vinyl cable (IV) for  connection 3f 3w 200V cable wiring is installed.
Ordering method